METHOD FOR REDUCING DYE FADING OF FABRICS IN LAUNDRY BLEACHING COMPOSITIONS

Abstract: A method of reducing dye fading of fabrics in laundry bleaching compositions is provided, comprising contacting stained fabric, in a wash liquor, with a bleaching composition that comprises a specified bleach catalyst. The bleach catalyst comprises a ligand which forms a complex with a transition metal, the complex catalysing bleaching of stains by atmospheric oxygen, and the composition is substantially devoid of peroxygen bleach or a peroxy-based or -generating bleach system. The bleaching composition provides effective bleaching performance on fabric stains without causing unacceptable dye damage or dye fading of the fabrics after repeated washes.

Description: METHOD FOR REDUCING DYE FADING OF FABRICS IN LAUNDRY BLEACHING COMPOSITIONS This invention relates to reducing dye fading of fabrics caused by laundry stain bleaching compositions, more particularly to reducing dye fading by using a bleaching composition that comprises a bleach catalyst having a ligand which forms a complex with a transition metal, the complex catalysing bleaching of stains by atmospheric oxygen. Peroxygen bleaches are well known for their ability to remove stains from substrates. Traditionally, the substrate is subjected to hydrogen peroxide, or to substances which can generate hydroperoxyl radicals, such as inorganic or organic peroxides. Generally, these systems must be activated. One method of activation is to employ wash temperatures of 60°C or higher. However, these high temperatures often lead to inefficient cleaning, and can also cause premature damage to the substrate. A preferred approach to generating hydroperoxyl bleach radicals is the use of inorganic peroxides coupled with organic precursor compounds. These systems are employed for many commercial laundry powders. For example, various European systems are based on tetraacetyl ethylenediamine (TAED) as the organic precursor coupled with sodium perborate or sodium percarbonate, whereas m the United States laundry bleach products are typically based on sodium nonanoyloxybenzenesulphonate (SNOBS) as the organic precursor coupled with sodium perborate. Precursor systems are generally effective but still exhibit several disadvantages. For example, organic precursors are moderately sophisticated molecules requiring multi-step manufacturing processes resulting in high capital costs. Also, precursor systems have large formulation space requirements so that a significant proportion of a laundry powder must be devoted to the bleach components, leaving less room for other active ingredients and complicating the development of concentrated powders. Moreover, precursor systems do not bleach very efficiently m countries where consumers have wash habits entailing low dosage, short wash times, cold temperatures and low wash liquor to substrate ratios . Alternatively, or additionally, hydrogen peroxide and peroxy systems can be activated by bleach catalysts, such as by complexes of iron and the ligand N4Py (i.e. N, N- bis (pyrιdιn-2-yl-methyl) -bis (pyrιdm-2-yl) methylamine) disclosed in W095/34628, or the ligand Tpen (i.e. N, N, N' , N' -tetra (pyrιdιn-2-yl-methyl) ethylenediamine) disclosed m W097/48787. EP-A-0909809 discloses a class of iron coordination complexes useful as catalysts for the bleach activation of peroxy compounds, including iron complexes comprising the ligand N, N-bis (pyridm-2-yl-methyl) -1, 1- bis (pyrιdιn-2-yl) -l-ammoethane, also referred to as MeN4Py. These catalysts are said to be useful in bleaching systems comprising a peroxy compound or a precursor thereof, such as in the washing and bleaching of substrates including laundry, dishwashing and hard surface cleaning, or for bleaching in the textile, paper and woodpulp industries, and m waste water treatment. According to these publications, molecular oxygen may be used as the oxidant as an alternative to peroxide generating systems. However, no role in catalysing bleaching by atmospheric oxygen in an aqueous medium is reported. It has long been thought desirable to be able to use atmospheric oxygen (air) as the source for a bleaching species, as this would avoid the need for costly hydroperoxyl generating systems. Unfortunately, air as such is kinetically inert towards bleaching substrates and exhibits no bleaching ability. Recently some progress has been made in this area. For example, WO 97/38074 reports the use of air for oxidising stains on fabrics by bubbling air through an aqueous solution containing an aldehyde and a radical initiator. A broad range of aliphatic, aromatic and heterocyclic aldehydes is reported to be useful, particularly para-substituted aldehydes such as 4-methyl-, 4-ethyl- and 4-isopropyl benzaldehyde, whereas the range of initiators disclosed includes N-hydroxysuccinimide, various peroxides and transition metal coordination complexes. However, although this system employs molecular oxygen from the air, the aldehyde component and radical initiators such as peroxides are consumed during the bleaching process. These components must therefore be included in the composition in relatively high amounts so as not to become depleted before completion of the bleaching process in the wash cycle. Moreover, the spent components represent a waste of resources as they can no longer participate in the bleaching process. Accordingly, it would be desirable to be able to provide a bleaching system based on atmospheric oxygen or air that does not rely primarily on hydrogen peroxide or a hydroperoxyl generating system, and that does not require the presence of organic components such as aldehydes that are consumed in the process. Moreover, it would be desirable to provide such a bleaching system that is effective in aqueous medium. Conventional bleaching systems based on hydrogen peroxide, peroxide compounds and/or peroxyacids with peracid precursors such as TAED can provide effective bleaching performance on a variety of stain types on fabrics. However, when present m the amounts necessary to ensure effective bleaching of stains, these bleaching systems can perceptibly damage the dyes used m the fabrics and thus result in unacceptable levels of dye fading after repeated laundry washing of the fabrics. It would therefore be desirable to be able to provide a bleaching composition and method for stain bleaching of laundry fabrics, which can yield comparable or improved stain bleaching performance on fabrics relative to conventional bleaching systems that employ peracid bleach precursors, whilst at the same time resulting in reduced dye damage and thus more acceptable levels of dye fading after repeated fabric washes. We have now found that these problem associated with the prior art may be solved by using a bleach catalyst that comprises a ligand which forms a complex with a transition metal, the complex catalysing bleaching of stains by atmospheric oxygen in the absence of peroxygen bleach or a peroxy-based or -generating bleach system, as specified herein. Accordingly, in a first aspect, the present invention provides a method of reducing dye fading of fabrics in laundry bleaching compositions, comprising contacting stained fabric, in a wash liquor, with a bleaching composition that comprises a bleach catalyst, wherein the bleach catalyst comprises a ligand which forms a complex with a transition metal, the complex catalysing bleaching of stains by atmospheric oxygen, and the composition is substantially devoid of peroxygen bleach or a peroxy-based or -generating bleach system. In a second aspect, the present invention provides the use of a bleach catalyst that comprises a ligand which forms a complex with a transition metal, the complex catalysing bleaching of stains by atmospheric oxygen in a bleaching composition in a wash liquor that is substantially devoid of peroxygen bleach or a peroxy-based or -generating bleach system, to reduce dye fading of fabrics contacted with the bleaching composition. We have found that the use of certain bleach catalysts, the most preferred of which is a complex of iron with the ligand N, N-bis (pyridin-2-yl-methyl) -1, 1-bis (pyridin-2-yl) -1- aminoethane (FeMeN4Py), in a bleaching composition in a wash liquor that is free of peroxygen bleach or a peroxy-based or -generating bleach system, gives much reduced dye fading compared to a conventional precursor/peroxide system such as TAED/percarbonate, whilst delivering equivalent or improved stain bleaching. The amount of catalyst in the composition according to the present invention is sufficient to provide a concentration in the wash liquor of preferably from 0.5 μM to 100 μM, more preferably from 1 μM to 10 μM The bleach catalyst used in the composition comprises a ligand which forms a complex with a transition metal, the complex catalysing bleaching of stains by atmospheric oxygen in the absence of peroxygen bleach or a peroxy-based or - generating bleach system. Suitable bleach catalysts are described further below. Preferably, the composition comprises FeMeN4Py as bleach catalyst. The catalyst may comprise a preformed complex of a ligand and a transition metal. Alternatively, the catalyst may comprise a free ligand that complexes with a transition metal already present in the water or that complexes with a transition metal present in the substrate. The catalyst may also be included in the form of a composition of a free ligand or a transition metal-substitutable metal-ligand complex, and a source of transition metal, whereby the complex is formed in si tu in the medium. The ligand forms a complex with one or more transition metals, in the latter case for example as a dinuclear complex. Suitable transition metals include for example: manganese in oxidation states II-V, iron II-V, copper I-III, cobalt I-III, titanium II-IV, tungsten IV-VI, vanadium II-V and molybdenum II-VI. The transition metal complex preferably is of the general formula: [M a L k X n ]Y m in which: M represents a metal selected from Mn (II) - (III) - (IV) - (V), Cu(I)-(II)-(III), Fe ( II) - ( III ) - ( IV) - (V) , Co(I)-(II)- (III), Ti(II)-(III)-(IV), V(II)-(III)-(IV)-(V), Mo(II)- (III) - ( IN) -(V)- (VI) and ( IV) - (V) - (VI ) , preferably from Fe(II)-(III)-(IV)-(V) ; L represents the ligand, preferably Ν,Ν-bis (pyridin-2- yl-methyl) -1, 1-bis (pyridin-2-yl) -1-aminoethane, or its protonated or deprotonated analogue; X represents a coordinating species selected from any mono, bi or tri charged anions and any neutral molecules able to coordinate the metal in a mono, bi or tridentate manner; Y represents any non-coordinated counter ion; a represents an integer from 1 to 10; k represents an integer from 1 to 10; n represents zero or an integer from 1 to 10; m represents zero or an integer from 1 to 20. Preferably, the complex is an iron complex comprising the ligand N,N-bis (pyridin-2-yl-methyl) -1, 1-bis (pyridin-2-yl) -1- aminoethane. However, it will be appreciated that the present invention may instead, or additionally, use other ligands and transition metal complexes, provided that the complex formed is capable of catalysing stain bleaching in the presence of peroxygen bleach or a peroxy-based or - generating bleach system. Suitable classes of ligands are described below: (A) Ligands of the general formula (IA): (IA) wherein Zl groups independently represent a coordinating group selected from hydroxy, amino, -NHR or -N(R) 2 (wherein R=Cι- 6 - alkyl), carboxylate, a ido, -NH-C (NH) NH 2 , hydroxyphenyl, a heterocyclic ring optionally substituted by one or more functional groups E or a heteroaromatic ring optionally substituted by one or more functional groups E, the heteroaromatic ring being selected from pyridine, pyrimidine, pyrazine, pyrazole, imidazole, benzimidazole, quinoline, quinoxaline, triazole, isoquinoline, carbazole, indole, isoindole, oxazole and thiazole; Ql and Q3 independently represent a group of the formula: wherein 5 > a+b+c > 1; a=0-5; b=0-5; c=0-5; n=0 or 1 (preferably n=0); Y independently represents a group selected from -0-, S-, -SO-, -S0 2 -, -C(O)-, arylene, alkylene, heteroarylene, heterocycloalkylene, -(G)P-, -P(0)- and -(G)N- , wherein G is selected from hydrogen, alkyl, aryl, arylalkyl, cycloalkyl, each except hydrogen being optionally substituted by one or more functional groups E; R5, R6, R7, R8 independently represent a group selected from hydrogen, hydroxyl, halogen, -R and -OR, wherein R represents alkyl, alkenyl, cycloalkyl, heterocycloalkyl, aryl, heteroaryl or a carbonyl derivative group, R being optionally substituted by one or more functional groups E, or R5 together with R6, or R7 together with R8, or both, represent oxygen, or R5 together with R7 and/or independently R6 together with R8, or R5 together with R8 and/or independently R6 together with R7, represent Cι- 6 -alkylene optionally substituted by Cι_ 4 -alkyl, -F, -Cl, -Br or -I; T represents a non-coordinated group selected from hydrogen, hydroxyl, halogen, -R and -OR, wherein R represents alkyl, alkenyl, cycloalkyl, heterocycloalkyl, aryl, arylalkyl, heteroaryl or a carbonyl derivative group, R being optionally substituted by one or more functional groups E (preferably T= -H, -OH, methyl, methoxy or benzyl); U represents either a non-coordinated group T independently defined as above or a coordinating group of the general formula (IIA) , (IIIA) or (IVA) : (HA) [IIIA) (IVA) wherein Q2 and Q4 are independently defined as for Ql and Q3; Q represents -N(T)- (wherein T is independently defined as above) , or an optionally substituted heterocyclic ring or an optionally substituted heteroaromatic ring selected from pyridme, pyrimidine, pyrazine, pyrazole, imidazole, benzimidazole, qumoline, quinoxaline, triazole, isoquinoline, carbazole, mdole, isoindole, oxazole and thiazole; Z2 is independently defined as for ZI; Z3 groups independently represent -N(T)- (wherein T is independently defined as above) ; Z4 represents a coordinating or non-coordinating group selected from hydrogen, hydroxyl, halogen, -NH-C (NH) NH 2 , -R and -OR, wherein R= alkyl, alkenyl, cycloalkyl, heterocycloalkyl, aryl, heteroaryl or a carbonyl derivative group, R being optionally substituted by one or more functional groups E, or Z4 represents a group of the general formula (IIAa) : ;iIAa) and 1 < 3 < 4. Preferably, ZI, Z2 and Z4 independently represent an optionally substituted heterocyclic ring or an optionally substituted heteroaromatic ring selected from pyridme, pyrimidine, pyrazme, pyrazole, imidazole, benzimidazole, qu olme, qu oxalme, triazole, lsoqumolme, carbazole, dole, isoindole, oxazole and thiazole. More preferably, ZI, Z2 and Z4 independently represent groups selected from optionally substituted pyrιdm-2-yl, optionally substituted ιmιdazol-2-yl, optionally substituted ιmιdazol-4-yl, optionally substituted pyrazol-1-yl, and optionally substituted qumolm-2-yl . Most preferred is that ZI, Z2 and Z4 each represent optionally substituted pyπdm-2-yl . The groups ZI, Z2 and Z4 if substituted, are preferably substituted by a group selected from Cι- 4 -alkyl, aryl, arylalkyl, heteroaryl, methoxy, hydroxy, nitro, ammo, carboxyl, halo, and carbonyl. Preferred is that ZI, Z2 and Z4 are each substituted by a methyl group. Also, we prefer that the ZI groups represent identical groups. Each Ql preferably represents a covalent bond or C1-C4- alkylene, more preferably a covalent bond, methylene or ethylene, most preferably a covalent bond. Group Q preferably represents a covalent bond or C1-C4- alkylene, more preferably a covalent bond. The groups R5 , R6 , R7 , R8 preferably independently represent a group selected from -H, hydroxy-Co-C2o _ alkyl , halo-Co-C 2 o~ alkyl , nitroso , f ormyl-Co-C 2 o _ alkyl , carboxyl-Co-C 2 o-alkyl and esters and salts thereof , carbamoyl-Co-C 2 o _ alkyl , sulfo-Co- C 2 fj-alkyl and esters and salts thereof , sulf amoyl-Co-C 2 o- alkyl , ammo-C 0 -C 2 o _ alkyl , aryl-Co-C 2 o-alkyl , C 0 -C 2 o-alkyl , alkoxy-C 0 -C 8 -alkyl, carbonyl-C 0 -C 6 -alkoxy, and C 0 -C 2 o _ alkylamide. Preferably, none of R5-R8 is linked together. Non-coordinated group T preferably represents hydrogen, hydroxy, methyl, ethyl, benzyl, or methoxy. In one aspect, the group U in formula (IA) represents a coordinating group of the general formula (IIA): (HA) According to this aspect, it is preferred that Z2 represents an optionally substituted heterocyclic ring or an optionally substituted heteroaromatic ring selected from pyridine, pyrimidine, pyrazine, pyrazole, imidazole, benzimidazole, quinoline, quinoxaline, triazole, isoquinoline, carbazole, indole, isoindole, oxazole and thiazole, more preferably optionally substituted pyridin-2-yl or optionally substituted benzimidazol-2-yl . It is also preferred, in this aspect, that Z4 represents an optionally substituted heterocyclic ring or an optionally substituted heteroaromatic ring selected from pyridine, pyrimidine, pyrazine, pyrazole, imidazole, benzimidazole, quinoline, quinoxaline, triazole, isoquinoline, carbazole, indole, isoindole, oxazole and thiazole, more preferably optionally substituted pyridin-2-yl, or an non-coordinating group selected from hydrogen, hydroxy, alkoxy, alkyl, alkenyl, cycloalkyl, aryl, or benzyl. In preferred embodiments of this aspect, the ligand is selected from: 1, 1-bis (pyridin-2-yl) -N-methyl-N- (pyridin-2- ylmethyl) methylamine; 1, 1-bis (pyridin-2-yl) -N, N-bis (6-methyl-pyridin-2- ylmethyl ) methylamine; 1, 1-bis (pyridin-2-yl) -N, N-bis (5-carboxymethyl-pyridin-2- ylmethyl ) methylamine ; 1, 1-bis (pyridin-2-yl) -1-benzyl-N, N-bis (pyridin-2- ylmethyl) methylamine; and 1, 1-bis (pyridin-2yl) -N, N-bis (benzimidazol-2- ylmethyl) methylamine . In a variant of this aspect, the group Z4 in formula (IIA) represents a group of the general formula (IIAa): (IIAa) In this variant, Q4 preferably represents optionally substituted alkylene, preferably -CH 2 -CHOH-CH 2 - or -CH 2 -CH 2 - CH 2 -. In a preferred embodiment of this variant, the ligand is : .Py Py . Py. Py 1— C— N N— C— H / X /^ \ / \ Py Py wherein -Py represents pyridin-2-yl . In another aspect, the group U in formula (IA) represents a coordinating group of the general formula (IIIA): :IIIA) wherein j is 1 or 2, preferably 1, According to this aspect, each Q2 preferably represents (CH 2 ) n - (n=2-4), and each Z3 preferably represents -N(R) wherem R = -H or Cι_ 4 -alkyl, preferably methyl. In preferred embodiments of this aspect, the ligand is selected from: wherein -Py represents pyridin-2-yl . In yet another aspect, the group U in formula (IA) represents a coordinating group of the general formula (IVA) : Q- IVA) In this aspect, Q preferably represents -N(T)- (wherein T= H, methyl, or benzyl) or pyridin-diyl . In preferred embodiments of this aspect, the ligand is selected from: P V H Py p y py \ I / \ / Me — C — — C— Me MeO — C— n ~ C — OMe / \ / \ Py Py Py Py P Py HO— c— n — — OH Py / \ Py wherein -Py represents pyridin-2-yl, and -Q- represents pyridin-2, 6-diyl. (B) Ligands of the general formula (IB) : I B ) wherein n = 1 or 2, whereby if n = 2, then each -Q 3 -R 3 group is independently defined; Ri. R 2 . R 3 . R. independently represent a group selected from hydrogen, hydroxyl, halogen, -NH-C (NH) NH 2 , -R and -OR, wherein R= alkyl, alkenyl, cycloalkyl, heterocycloalkyl, aryl, heteroaryl or a carbonyl derivative group, R being optionally substituted by one or more functional groups E, Qi, Q 2 , Q 3 , Q 4 and Q independently represent a group of the formula: wherein 5 > a+b+c > 1; a=0-5; b=0-5; c=0-5; n=l or 2; Y independently represents a group selected from -0-, - S-, -SO-, -S0 2 -, -C(O)-, arylene, alkylene, heteroarylene, heterocycloalkylene, -(G)P-, -P(O)- and -(G)N- , wherem G is selected from hydrogen, alkyl, aryl, arylalkyl, cycloalkyl, each except hydrogen being optionally substituted by one or more functional groups E; R5, R6, R7, R8 independently represent a group selected from hydrogen, hydroxyl, halogen, -R and -OR, wherem R represents alkyl, alkenyl, cycloalkyl, heterocycloalkyl, aryl, heteroaryl or a carbonyl derivative group, R being optionally substituted by one or more functional groups E, or R5 together with R6, or R7 together with R8, or both, represent oxygen, or R5 together with R7 and/or independently R6 together with R8, or R5 together with R8 and/or independently R6 together with R7 , represent Cι_ 6 -alkylene optionally substituted by Cι--alkyl, -F, -Cl, -Br or -I, provided that at least two of Ri, R 2 , R 3 , R comprise coordinating heteroatoms and no more than six heteroatoms are coordinated to the same transition metal atom. At least two, and preferably at least three, of Ri, R 2 , R 3 , R 4 independently represent a group selected from carboxylate, amido, -NH-C (NH) NH 2 , hydroxyphenyl, an optionally substituted heterocyclic ring or an optionally substituted heteroaromatic ring selected from pyridme, pyrimidine, pyrazine, pyrazole, imidazole, benzimidazole, quinoline, quinoxaline, triazole, isoquinoline, carbazole, indole, isoindole, oxazole and thiazole. Preferably, substituents for groups Ri, R 2 , R 3 , R 4 , when representing a heterocyclic or heteroaromatic ring, are selected from Cι_-alkyl, aryl, arylalkyl, heteroaryl, methoxy, hydroxy, nitro, amino, carboxyl, halo, and carbonyl . The groups Qi, Q 2 , Q 3 , Q 4 preferably independently represent a group selected from -CH 2 - and -CH 2 CH 2 -. Group Q is preferably a group selected from -(CH 2 ) 2 - 4 -, - CH 2 CH(OH)CH 2 -, optionally substituted by methyl or ethyl, wherein R represents -H or Cι--alkyl Preferably, Qi, Q 2 , Q 3 , Q 4 are defined such that a=b=0, c=l and n=l, and Q is defined such that a=b=0, c=2 and n=l. The groups R5, R6, R7 , R8 preferably independently represent a group selected from -H, hydroxy-Co-C 2 o-alkyl, halo-Co-C 2 o~ alkyl, nitroso, formyl-Co-C2o-alkyl, carboxyl-C 0 -C 2 o _ alkyl and esters and salts thereof, carbamoyl-Co-C2o-alkyl, sulfo-Co- C2o~alkyl and esters and salts thereof, sulfamoyl-Co-C2o~ alkyl, amino-Co-C 2 o-alkyl, aryl-Co-C2o _ alkyl, Co _ C 2 o-alkyl, alkoxy-Co-Cβ-alkyl, carbonyl-Crj-Ce-alkoxy, and C 0 -C20- alkylamide. Preferably, none of R5-R8 is linked together. In a preferred aspect, the ligand is of the general formula (IIB) : R-i Q-i Q—R_ t N-Q-N R 2 Q Q 3 —R 3 (IIB) wherein Qif Q 2 Q3. Q. ar e defined such that a=b=0, c=l or 2 and n=l; Q is defined such that a=b=0, c=2,3 or 4 and n=l; and Ri. 2 A R3. R4. 7 , R8 are independently defined as for formula (I ) . Preferred classes of ligands according to this aspect, as represented by formula (IIB) above, are as follows: (i) ligands of the general formula (IIB) wherein: Ri, R 2 , R 3 , R 4 each independently represent a coordinating group selected from carboxylate, amido, -NH- C(NH)NH 2 , hydroxyphenyl, an optionally substituted heterocyclic ring or an optionally substituted heteroaromatic ring selected from pyridine, pyrimidine, pyrazine, pyrazole, imidazole, benzimidazole, quinoline, quinoxaline, triazole, isoquinoline, carbazole, indole, isoindole, oxazole and thiazole. In this class, we prefer that: Q is defined such that a=b=0, c=2 or 3 and n=l; Ri, R 2 , R 3 , R 4 each independently represent a coordinating group selected from optionally substituted pyπdm-2-yl, optionally substituted ιmιdazol-2-yl, optionally substituted ιmιdazol-4-yl, optionally substituted pyrazol-1-yl, and optionally substituted qumolm-2-yl . (ii) ligands of the general formula (IIB) wherem: Ri, R 2 , R 3 each independently represent a coordinating group selected from carboxylate, amido, -NH-C (NH) NH 2 , hydroxyphenyl, an optionally substituted heterocyclic ring or an optionally substituted heteroaromatic ring selected from pyridme, pyrimidine, pyrazine, pyrazole, imidazole, benzimidazole, quinoline, quinoxaline, triazole, isoquinoline, carbazole, indole, isoindole, oxazole and thiazole; and R represents a group selected from hydrogen, C 1 - 20 optionally substituted alkyl, Cι_ 2 o optionally substituted arylalkyl, aryl, and Cι_ 2 o optionally substituted NR 3 + (wherem R=Cι_ 8 -alkyl) . In this class, we prefer that: Q is defined such that a=b=0, c=2 or 3 and n=l; Ri. R 2 . R3 each independently represent a coordinating group selected from optionally substituted pyrιdm-2-yl, optionally substituted ιmιdazol-2-yl, optionally substituted ιmιdazol-4-yl, optionally substituted pyrazol-1-yl, and optionally substituted qumolm-2-yl; and R 4 represents a group selected from hydrogen, Cι- 10 optionally substituted alkyl, Cι- 5 -furanyl, C 1 - 5 optionally substituted benzylalkyl, benzyl, C 1 -. 5 optionally substituted alkoxy, and C1-20 optionally substituted N + Me 3 . [in) ligands of the general formula (IIB) wherem: Ri, R 4 each independently represent a coordinating group selected from carboxylate, amido, -NH-C (NH) NH 2 , hydroxyphenyl, an optionally substituted heterocyclic ring or an optionally substituted heteroaromatic ring selected from pyrid e, pyrimidine, pyrazine, pyrazole, imidazole, benzimidazole, quinoline, quinoxaline, triazole, isoquinoline, carbazole, indole, isoindole, oxazole and thiazole; and R 2 , R 3 each independently represent a group selected from hydrogen, C1-20 optionally substituted alkyl, C1-20 optionally substituted arylalkyl, aryl, and Cι_ 2 o optionally substituted NR 3 + (where R=C 1 _ 8 -alkyl) . In this class, we prefer that: Q is defined such that a=b=0, c=2 or 3 and n=l; Ri, R 4 each independently represent a coordinating group selected from optionally substituted pyπdm-2-yl, optionally substituted ιmιdazol-2-yl, optionally substituted ιmιdazol-4-yl, optionally substituted pyrazol-1-yl, and optionally substituted qumolm-2-yl; and R 2 , R 3 each independently represent a group selected from hydrogen, Cι-10 optionally substituted alkyl, C1-.5- furanyl, Cι_ optionally substituted benzylalkyl, benzyl, Cι_ 5 optionally substituted alkoxy, and C1-20 optionally substituted N + Me 3 . Examples of preferred ligands in their simplest forms are: N,N' , N ' -tris (3-methyl-pyπdιn-2-ylmethyl) -ethylenediamme; N-trimethylammoniumpropyl-N, N ' , N ' -tris (pyrιdm-2-ylmethyl) - ethylenediamme; N- (2-hydroxyethylene) -N, N' , N ' -tris (pyridin-2-ylmethyl) - ethylenediamine ; N,N,N' , N ' -tetrakis ( 3-methyl-pyridin-2-ylmethyl) -ethylenediamine; N, N ' -dimethyl-N, N ' -bis (pyridin-2-ylmethyl) -cyclohexane-1, 2- diamine; N- (2-hydroxyethylene) -N,N' , N ' -tris ( 3-methy1-pyridin-2- ylmethyl ) -ethylenediamine; N-methyl-N, N ' , N ' -tris (pyridin-2-ylmethyl ) -ethylenediamine; N-methyl-N, N' ,N' -tris ( 5-ethyl-pyridin-2-ylmethyl ) - ethylenediamine ; N-methyl-N, N' , N ' -tris ( 5-methyl-pyridin-2-ylmethyl) - ethylenediamine; N-methyl-N, N ' , N ' -tris (3-methyl-pyridin-2-ylmethyl) - ethylenediamine; N-benzyl-N,N' , N' -tris (3-methyl-pyridin-2-ylmethyl) - ethylenediamine; N-ethyl-N,N' ,N' -tris (3-methyl-pyridin-2-ylmethyl ) - ethylenediamine; N,N,N'-tris (3-methyl-pyridin-2-ylmethyl ) -N ' (2'-methoxy- ethyl-1) -ethylenediamine; N,N,N'-tris ( l-methyl-benzimidazol-2-yl) -N ' -methyl- ethylenediamine; N- (furan-2-yl) -N,N' ,N' -tris (3-methyl-pyridin-2-ylmethyl) - ethylenediamine; N- (2-hydroxyethylene) -N, N ' , N ' -tris (3-ethyl-pyridin-2- ylmethyl) -ethylenediamine; N-methyl-N, N' , N' -tris (3-methyl-pyridin-2-ylmethyl) ethylene- 1,2-diamine; N-ethyl-N, N' , N' -tris (3-methyl-pyridin-2-ylmethyl) ethylene- 1, 2-diamine; N-benzyl-N, N' , N' -tris ( 3-methyl-pyridin-2-ylmethyl ) ethylene- 1, 2-diamine; N- (2-hydroxyethyl) -N,N' ,N'-tris ( 3-methy1-pyridin-2- ylmethyl) ethylene-1, 2-diamine; N- (2-methoxyethyl) -N,N' , N' -tris (3-methyl-pyridin-2- ylmethyl) ethylene-1, 2-diamine; N-methyl-N, N' , N' -tris ( 5-methyl-pyridin-2-ylmethy1 ) ethylene- 1, 2-diamine; N-ethyl-N, N' , N' -tris ( 5-methyl-pyridin-2-ylmethy1 ) ethylene- 1, 2-diamine; N-benzyl-N, N' ,N' -tris (5-methyl-pyridin-2-ylmethyl) ethylene- 1, 2-diamine; N- (2-hydroxyethyl) -N,N' , N' -tris (5-methyl-pyridin-2- ylmethyl) ethylene-1, 2-diamine; N- (2-methoxyethyl) -N,N' , N' -tris (5-methyl-pyridin-2- ylmethyl) ethylene-1, 2-diamine; N-methyl-N, N' , N' -tris (3-ethyl-pyridin-2-ylmethyl) ethylene- 1, 2-diamine; N-ethyl-N, N' ,N' -tris ( 3-ethyl-pyridin-2-ylmethyl) ethylene- 1, 2-diamine; N-benzyl-N, N' , N' -tris (3-ethyl-pyridin-2-ylmethyl) ethylene- 1, 2-diamine; N- (2-hydroxyethyl) -N,N' ,N' -tris (3-ethyl-pyridin-2- ylmethyl) ethylene-1, 2-diamine; N- (2-methoxyethyl) -N,N' ,N' -tris (3-ethyl-pyridin-2- ylmethyl) ethylene-1, 2-diamine; N-methyl-N, N' , N' -tris ( 5-ethyl-pyridin-2-ylmethy1 ) ethylene- 1, 2-diamine; N-ethyl-N, N' , N' -tris (5-ethyl-pyridin-2-ylmethyl) ethylene- 1, 2-diamine; N-benzyl-N, N' , N' -tris (5-ethyl-pyridin-2-ylmethyl) ethylene- 1, 2-diamine; and N- (2-methoxyethyl) -N,N' ,N' -tris ( 5-ethyl-pyridin-2- ylmethyl) ethylene-1, 2-diamine. More preferred ligands are: N-methyl-N, N' , N' -tris ( 3-methyl-pyridin-2-ylmethy1 ) ethylene- 1, 2-diamine; N-ethyl-N, N' ,N' -tris ( 3-methyl-pyridin-2-ylmethy1 ) ethylene- 1, 2-diamine; N-benzyl-N, N' , N' -tris (3-methyl-pyridin-2-ylmethyl) ethylene- 1, 2-diamine; N- (2-hydroxyethyl) -N,N' , N' -tris (3-methyl-pyridin-2- ylmethyl) ethylene-1, 2-diamine; and N- (2-methoxyethyl) -N, N' , N' -tris (3-methyl-pyridin-2- ylmethyl) ethylene-1, 2-diamine . [C) Ligands of the general formula (IC) wherein Zi, Z 2 and Z 3 independently represent a coordinating group selected from carboxylate, amido, -NH-C (NH) NH 2 , hydroxyphenyl, an optionally substituted heterocyclic ring or an optionally substituted heteroaromatic ring selected from pyridine, pyrimidine, pyrazine, pyrazole, imidazole, benzimidazole, quinoline, quinoxaline, triazole, isoquinoline, carbazole, indole, isoindole, oxazole and thiazole; Qi, Q 2 . and Q 3 independently represent a group of the formula : wherein 5 > a+b+c > 1; a=0-5; b=0-5; c=0-5; n=l or 2; Y independently represents a group selected from -0-, S-, -SO-, -S0 2 -, -C(0)-, arylene, alkylene, heteroarylene, heterocycloalkylene, -(G)P-, -P(O)- and -(G)N- , wherein G is selected from hydrogen, alkyl, aryl, arylalkyl, cycloalkyl, each except hydrogen being optionally substituted by one or more functional groups E; and R5, R6, R7, R8 independently represent a group selected from hydrogen, hydroxyl, halogen, -R and -OR, wherein R represents alkyl, alkenyl, cycloalkyl, heterocycloalkyl, aryl, heteroaryl or a carbonyl derivative group, R being optionally substituted by one or more functional groups E, or R5 together with R6, or R7 together with R8 , or both, represent oxygen, or R5 together with R7 and/or independently R6 together with R8, or R5 together with R8 and/or independently R6 together with R7, represent Cι- 6 -alkylene optionally substituted by Cι--alkyl, -F, -Cl, -Br or -I. Zi, Z 2 and Z 3 each represent a coordinating group, preferably selected from optionally substituted pyridin-2-yl, optionally substituted imidazol-2-yl, optionally substituted imidazol-4-yl, optionally substituted pyrazol-1-yl, and optionally substituted quinolin-2-yl . Preferably, Z x , Z 2 and Z 3 each represent optionally substituted pyridin-2-yl . Optional substituents for the groups Zi, Z and Z 3 are preferably selected from Cι- 4 -alkyl, aryl, arylalkyl, heteroaryl, methoxy, hydroxy, nitro, amino, carboxyl, halo, and carbonyl, preferably methyl. Also preferred is that Qi, Q 2 and Q 3 are defined such that a=b=0, c=l or 2, and n=l. Preferably, each Qi, Q 2 and Q 3 independently represent Cι- 4 - alkylene, more preferably a group selected from -CH 2 - and - CH2CH2-. The groups R5, R6, R7 , R8 preferably independently represent a group selected from -H, hydroxy-Co-C 2 o~alkyl, halo-Co-C 2 o _ alkyl, nitroso, formyl-Co-C 2 o _ alkyl, carboxyl-C 0 -C 2 o _ alkyl and esters and salts thereof, carbamoyl-Co-C 2 o _ alkyl, sulfo-C 0 - C 2 o _ alkyl and esters and salts thereof, sulfamoyl-Co-C 2 o~ alkyl, amino-Co-C 2 o-alkyl, aryl-Co-C 2 o-alkyl, Co-C 2 o _ alkyl, alkoxy-C 0 -C 8 -alkyl, carbonyl-C 0 -C 6 -alkoxy, and C 0 -C 2 o- alkylamide. Preferably, none of R5-R8 is linked together. Preferably, the ligand is selected from tris (pyridin-2- ylmethyl) amine, tris (3-methyl-pyridin-2-ylmethyl) amine, tris (5-methyl-pyridin-2-ylmethyl) amine, and tris (6-methyl- pyridin-2-ylmethyl ) amine . [D) Ligands of the general formula (ID) Ri \ Q^ / Q^ / Q 2 -R 2 ^N N Q. ,Q N ' Q 3 3 κ ( I D ) wherein Ri, R 2 , and R 3 independently represent a group selected from hydrogen, hydroxyl, halogen, -NH-C (NH) NH 2 , -R and -OR, wherein R= alkyl, alkenyl, cycloalkyl, heterocycloalkyl, aryl, heteroaryl or a carbonyl derivative group, R being optionally substituted by one or more functional groups E; Q independently represent a group selected from C 2 _ 3 - alkylene optionally substituted by H, benzyl or Ci-β-alkyl; Qi. Q 2 and Q 3 independently represent a group of the formula: wherein 5 > a+b+c > 1; a=0-5; b=0-5; c=0-5; n=l or 2; Y independently represents a group selected from -0-, S-, -SO-, -S0 2 -, -C(O)-, arylene, alkylene, heteroarylene, heterocycloalkylene, -(G)P-, -P(O)- and -(G)N- , wherein G is selected from hydrogen, alkyl, aryl, arylalkyl, cycloalkyl, each except hydrogen being optionally substituted by one or more functional groups E; and R5, R6, R7, R8 independently represent a group selected from hydrogen, hydroxyl, halogen, -R and -OR, wherein R represents alkyl, alkenyl, cycloalkyl, heterocycloalkyl, aryl, heteroaryl or a carbonyl derivative group, R being optionally substituted by one or more functional groups E, or R5 together with R6, or R7 together with R8, or both, represent oxygen, or R5 together with R7 and/or independently R6 together with R8, or R5 together with R8 and/or independently R6 together with R7 , represent Cι- 6 -alkylene optionally substituted by Cι_-alkyl, -F, -Cl, -Br or -I, provided that at least one, preferably at least two, of Ri, R 2 and R 3 is a coordinating group. At least two, and preferably at least three, of Ri, R2 and R 3 independently represent a group selected from carboxylate, amido, -NH-C (NH) NH 2 , hydroxyphenyl, an optionally substituted heterocyclic ring or an optionally substituted heteroaromatic ring selected from pyridine, pyrimidine, pyrazine, pyrazole, imidazole, benzimidazole, quinoline, quinoxaline, triazole, isoquinoline, carbazole, indole, isoindole, oxazole and thiazole. Preferably, at least two of Ri, R 2 , R 3 each independently represent a coordinating group selected from optionally substituted pyridin-2-yl, optionally substituted imidazol-2-yl, optionally substituted imidazol-4-yl, optionally substituted pyrazol-1-yl, and optionally substituted quinolin-2-yl . Preferably, substituents for groups Ri, R2, R 3 , when representing a heterocyclic or heteroaromatic ring, are selected from Cι- 4 -alkyl, aryl, arylalkyl, heteroaryl, methoxy, hydroxy, nitro, amino, carboxyl, halo, and carbonyl . Preferably, Qi, Q2 and Q 3 are defined such that a=b=0, c=l,2,3 or 4 and n=l. Preferably, the groups G , Q 2 and Q 3 independently represent a group selected from -CH 2 - and - CH2CH2-. Group Q is preferably a group selected from -CH 2 CH 2 - and - CH2CH2CH2-. The groups R5, R6, R7 , R8 preferably independently represent a group selected from -H, hydroxy-Co-Co _ alkyl, halo-Co-C∑o- alkyl, nitroso, formyl-Co-C 2 o-alkyl, carboxyl-Co-C 2 o~alkyl and esters and salts thereof, carbamoyl-Co-C 2 o _ alkyl, sulfo-C 0 - C2o~alkyl and esters and salts thereof, sulfamoyl-C 0 -C2o~ alkyl, amino-C 0 -C2o _ alkyl, aryl-C 0 -C2o _ alkyl, Co-C 2 o _ alkyl, alkoxy-Co-Cs-alkyl, carbonyl-C 0 -C 6 -alkoxy, and C 0 -C 20 - alkylamide. Preferably, none of R5-R8 is linked together. In a preferred aspect, the ligand is of the general formula (IID) : IID) wherein RI, R2, R3 are as defined previously for Ri, R 2 , R 3 , and Qi, Q 2 , Q 3 are as defined previously. Preferred classes of ligands according to this preferred aspect, as represented by formula (IID) above, are as follows : (i) ligands of the general formula (IID) wherein: RI, R2, R3 each independently represent a coordinating group selected from carboxylate, amido, -NH-C (NH) NH2, hydroxyphenyl, an optionally substituted heterocyclic ring or an optionally substituted heteroaromatic ring selected from pyridine, pyrimidine, pyrazine, pyrazole, imidazole, benzimidazole, quinoline, quinoxaline, triazole, isoquinoline, carbazole, indole, isoindole, oxazole and thiazole . In this class, we prefer that: RI, R2, R3 each independently represent a coordinating group selected from optionally substituted pyridin-2-yl, optionally substituted imidazol-2-yl, optionally substituted imidazol-4-yl, optionally substituted pyrazol-1-yl, and optionally substituted quinolin-2-yl . (ii) ligands of the general formula (IID) wherein: two of RI, R2, R3 each independently represent a coordinating group selected from carboxylate, amido, -NH- C(NH)NH 2 , hydroxyphenyl, an optionally substituted heterocyclic ring or an optionally substituted heteroaromatic ring selected from pyridine, pyrimidine, pyrazine, pyrazole, imidazole, benzimidazole, quinoline, quinoxaline, triazole, isoquinoline, carbazole, indole, isoindole, oxazole and thiazole; and one of RI, R2 , R3 represents a group selected from hydrogen, Cι_ 2 o optionally substituted alkyl, Cι- 2 o optionally substituted arylalkyl, aryl, and Cι_ 2 o optionally substituted NR 3 + (wherein R=Cι_ 8 -alkyl) . In this class, we prefer that: two of RI, R2, R3 each independently represent a coordinating group selected from optionally substituted pyridin-2-yl, optionally substituted imidazol-2-yl, optionally substituted imidazol-4-yl, optionally substituted pyrazol-1-yl, and optionally substituted qumolin-2-yl; and one of RI, R2 , R3 represents a group selected from hydrogen, Ci-io optionally substituted alkyl, Cι_5-furanyl, Cι_ 5 optionally substituted benzylalkyl, benzyl, Cι- 5 optionally substituted alkoxy, and C1-20 optionally substituted N + Me 3 . In especially preferred embodiments, the ligand is selected from: wherein -Et represents ethyl, -Py represents pyridin-2-yl, Pz3 represents pyrazol-3-yl, Pzl represents pyrazol-1-yl, and Qu represents quinolin-2-yl . (E) Ligands of the general formula (IE) : TI- [-N- (QI ) r -] s —N- (Q2 ) g -T2 I I RI R2 (IE) wherein g represents zero or an integer from 1 to 6; r represents an integer from 1 to 6; s represents zero or an integer from 1 to 6; QI and Q2 independently represent a group of the formula : ^ [-c-] d - -Yl-] e -[-C-]f R7 R9 wherein 5 ^d+e+f > 1; d=0-5; e=0-5; f=0-5; each YI independently represents a group selected from -0-, -S-, -SO-, -S0 2 -, -C(0)-, arylene, alkylene, heteroarylene, heterocycloalkylene, -(G)P-, -P(O)- and - (G)N- , wherein G is selected from hydrogen, alkyl, aryl, arylalkyl, cycloalkyl, each except hydrogen being optionally substituted by one or more functional groups E; if s>l, each - [-N (RI) - (QI) r -] - group is independently defined; RI, R2, R6, R7, R8, R9 independently represent a group selected from hydrogen, hydroxyl, halogen, -R and -OR, wherein R represents alkyl, alkenyl, cycloalkyl, heterocycloalkyl, aryl, heteroaryl or a carbonyl derivative group, R being optionally substituted by one or more functional groups E, or R6 together with R7, or R8 together with R9, or both, represent oxygen, or R6 together with R8 and/or independently R7 together with R9, or R6 together with R9 and/or independently R7 together with R8 , represent Cι- 6 -alkylene optionally substituted by Cι- 4 -alkyl, -F, -Cl, -Br or -I; or one of R1-R9 is a bridging group bound to another moiety of the same general formula; TI and T2 independently represent groups R4 and R5, wherein R4 and R5 are as defined for R1-R9, and if g=0 and s>0, Rl together with R4 , and/or R2 together with R5, may optionally independently represent =CH-R10, wherein RIO is as defined for R1-R9, or TI and T2 may together (-T2-T1-) represent a covalent bond linkage when s>l and g>0; if TI and T2 together represent a single bond linkage, QI and/or Q2 may independently represent a group of the formula: =CH— [—YI—] e —CH= provided Rl and/or R2 are absent, and Rl and/or R2 may be absent provided QI and/or Q2 independently represent a group of the formula: =CH— [—YI—] e —CH=. The groups R1-R9 are preferably independently selected from -H, hydroxy-Co-C 2 o _ alkyl, halo-Co-C2o _ alkyl, nitroso, formyl- Co-C 2 o _ alkyl, carboxyl-C 0 -C 2 o _ alkyl and esters and salts thereof, carbamoyl-Co-C 2 o-alkyl, sulpho-C 0 -C 2 o~alkyl and esters and salts thereof, sulphamoyl-Co-C 2 o _ alkyl, amino-C 0 - C 2 o _ alkyl, aryl-Co-C 20 -alkyl, heteroaryl-C 0 -C 2 o _ alkyl, Co-C 2 o _ alkyl, alkoxy-Co-Cs-alkyl, carbonyl-Co-C 6 -alkoxy, and aryl-Cr . - Cε-alkyl and Co-Co-alkylamide . One of R1-R9 may be a bridging group which links the ligand moiety to a second ligand moiety of preferably the same general structure. In this case the bridging group is independently defined according to the formula for QI, Q2, preferably being alkylene or hydroxy-alkylene or a heteroaryl-containing bridge, more preferably Ci_ 6 -alkylene optionally substituted by Cι- 4 -alkyl, -F, -Cl, -Br or -I. In a first variant according to formula (IE), the groups TI and T2 together form a single bond linkage and s>l, according to general formula (HE): : I IE ) wherein R3 independently represents a group as defined for R1-R9; Q3 independently represents a group as defined for QI, Q2; h represents zero or an integer from 1 to 6; and s=s-l . In a first embodiment of the first variant, in general formula (HE), £=1, 2 or 3; r=g=h=l; d=2 or 3; e=f=0; R6=R7=H, preferably such that the ligand has a general formula selected from: In these preferred examples, Rl, R2, R3 and R4 are preferably independently selected from -H, alkyl, aryl, heteroaryl, and/or one of R1-R4 represents a bridging group bound to another moiety of the same general formula and/or two or more of R1-R4 together represent a bridging group linking N atoms in the same moiety, with the bridging group being alkylene or hydroxy-alkylene or a heteroaryl- containing bridge, preferably heteroarylene . More preferably, Rl, R2, R3 and R4 are independently selected from -H, methyl, ethyl, isopropyl, nitrogen-containing heteroaryl, or a bridging group bound to another moiety of the same general formula or linking N atoms in the same moiety with the bridging group being alkylene or hydroxy- alkylene . In a second embodiment of the first variant, in general formula (HE), s_=2 and r=g=h=l, according to the general formula : R3 ,03 N. R4. N Φ Q k N. ~ R2 N QI Rl In this second embodiment, preferably R1-R4 are absent; both QI and Q3 represent =CH— [—YI—] e —CH= ; and both Q2 and Q4 represent —CH 2 — [—YI—] n —CH 2 —. Thus, preferably the ligand has the general formula: wherein A represents optionally substituted alkylene optionally interrupted by a heteroatom; and n is zero or an integer from 1 to 5. Preferably, R1-R6 represent hydrogen, n=l and A= -CH 2 -, - CHOH-, -CH 2 N(R)CH 2 - or -CH 2 CH 2 N (R) CH 2 CH 2 - wherein R represents hydrogen or alkyl, more preferably A= -CH 2 -, -CHOH- or - CH 2 CH 2 NHCH 2 CH2-. In a second variant according to formula (IE), TI and T2 independently represent groups R4 , R5 as defined for R1-R9, according to the general formula (HIE): R4- ■ [-N-(Ql) r -] !Q2) q -R5 Rl R2 ' HIE) In a first embodiment of the second variant, in general formula (HIE), s=l; r=l; g=0; d=f=l; e=0-4; Yl= -CH 2 -; and Rl together with R4, and/or R2 together with R5, independently represent =CH-R10, wherein RIO is as defined for R1-R9. In one example, R2 together with R5 represents =CH-R10, with Rl and R4 being two separate groups. Alternatively, both Rl together with R4, and R2 together with R5 may independently represent =CH-R10. Thus, preferred ligands may for example have a structure selected from: wherein n = 0-4 Preferably, the ligand is selected from: =N N= R 4 —N N= ι κ R 3 i wherein Rland R2 are selected from optionally substituted phenols, heteroaryl-Co-C 2 o-alkyls, R3 and R4 are selected from -H, alkyl, aryl, optionally substituted phenols, heteroaryl-Co-C2o~alkyls, alkylaryl, aminoalkyl, alkoxy, more preferably Rl and R2 being selected from optionally substituted phenols, heteroaryl-C 0 -C 2 -alkyls, R3 and R4 are selected from -H, alkyl, aryl, optionally substituted phenols, nitrogen-heteroaryl-C 0 -C 2 -alkyls . In a second embodiment of the second variant, in general formula (HIE), s=l; r=l; g=0; d=f=l; e=l-4; Yl= -CfR'MR' 1 wherein R' and R" are independently as defined for R1-R9. Preferably, the ligand has the general formula: The groups Rl, R2, R3, R4 , R5 in this formula are preferably -H or C 0 -C 20 -alkyl, n=0 or 1, R6 is -H, alkyl, -OH or -SH, and R7, R8, R9, RIO are preferably each independently selected from -H, C 0 -C 2 o-alkyl, heteroaryl-Co-Co-alkyl, alkoxy-Co-Cs-alkyl and amino-Co-Co-alkyl . In a third embodiment of the second variant, in general formula (HIE), s=0; g=l; d=e=0; f=l-4. Preferably, the ligand has the general formula: This class of ligand is particularly preferred according to the invention. More preferably, the ligand has the general formula: wherein Rl, R2, R3 are as defined for R2, R4 , R5. In a fourth embodiment of the second variant, the ligand is a pentadentate ligand of the general formula (IVE): (IVE) wherein each R 1 , R 2 independently represents -R-R 5 , R 3 represents hydrogen, optionally substituted alkyl, aryl or arylalkyl, or -R 4 -R 5 , each R 4 independently represents a single bond or optionally substituted alkylene, alkenylene, oxyalkylene, aminoalkylene, alkylene ether, carboxylic ester or carboxylic amide, and each R 5 independently represents an optionally N- substituted aminoalkyl group or an optionally substituted heteroaryl group selected from pyridinyl, pyrazinyl, pyrazolyl, pyrrolyl, imidazolyl, benzimidazolyl, pyrimidinyl, triazolyl and thiazolyl. Ligands of the class represented by general formula (IVE) are also particularly preferred according to the invention. The ligand having the general formula (IVE), as defined above, is a pentadentate ligand. By ^pentadentate' herein is meant that five hetero atoms can coordinate to the metal M ion in the metal-complex. In formula (IVE), one coordinating hetero atom is provided by the nitrogen atom in the methylamine backbone, and preferably one coordinating hetero atom is contained in each of the four R 1 and R 2 side groups. Preferably, all the coordinating hetero atoms are nitrogen atoms. The ligand of formula (IVE) preferably comprises at least two substituted or unsubstituted heteroaryl groups in the four side groups. The heteroaryl group is preferably a pyridin-2-yl group and, if substituted, preferably a methyl- or ethyl-substituted pyridin-2-yl group. More preferably, the heteroaryl group is an unsubstituted pyridin-2-yl group. Preferably, the heteroaryl group is linked to methylamine, and preferably to the N atom thereof, via a ethylene group. Preferably, the ligand of formula (IVE) contains at least one optionally substituted amino-alkyl side group, more preferably two amino-ethyl side groups, in particular 2-(N- alkyl) amino-ethyl or 2- (N, N-dialkyl) amino-ethyl . Thus, in formula (IVE) preferably R 1 represents pyridin-2-yl or R 2 represents pyridin-2-yl-methyl . Preferably R 2 or R 1 represents 2-amino-ethyl, 2- (N- (m) ethyl) amino-ethyl or 2- (N, N-di (m) ethyl) amino-ethyl . If substituted, R 5 preferably represents 3-methyl pyridin-2-yl . R 3 preferably represents hydrogen, benzyl or methyl. Examples of preferred ligands of formula (IVE) in their simplest forms are: (i) pyridin-2-yl containing ligands such as: N, N-bis (pyridin-2-yl-methyl) -bis (pyridin-2-yl) methylamine; N, N-bis (pyrazol-1-yl-methyl) -bis (pyridin-2-yl) methylamine; N, N-bis ( imidazol-2-yl-methyl) -bis (pyridin-2-yl) methylamine ; N, N-bis (1,2, 4-triazol-l-yl-methyl) -bis (pyridin-2- yl ) methylamine ; N, N-bis (pyridin-2-yl-methyl) -bis (pyrazol-l-yl)methylamine; N, N-bis (pyridin-2-yl-methyl) -bis (imidazol-2-yl) methylamine; N, N-bis (pyridin-2-yl-methyl) -bis (1, 2, 4-triazol-l- yl ) methylamine ; N, N-bis (pyridin-2-yl-methyl) -1, 1-bis (pyridin-2-yl) -1- aminoethane; N, -bis (pyridin-2-yl-methyl) -1, 1-bis (pyridin-2-yl) -2-phenyl- 1-aminoethane ; N , N-bi s ( pyra zol- 1 -yl-methyl ) - 1 , 1 -bi s ( pyridin-2 -yl ) - 1 - aminoethane; N, N-bis (pyrazol-1-yl-methyl) -1, 1-bis (pyridin-2-yl) -2-phenyl- 1-aminoethane; N, N-bis ( imidazol-2-yl-methyl) -1, 1-bis (pyridin-2-yl) -1- aminoethane; N, N-bis (imidazol-2-yl-methyl) -1, 1-bis (pyridin-2-yl) -2- phenyl-1-aminoethane; N, N-bis (1,2, -triazol-l-yl-methyl) -1, 1-bis (pyridin-2-yl) -1- aminoethane; N, N-bis (1,2, 4-triazol-l-yl-methyl) -1, 1-bis (pyridin-2-yl) -2- phenyl-1-aminoethane; N, N-bis (pyridin-2-yl-methyl) -1, 1-bis (pyrazol-1-yl) -1- aminoethane; N, N-bis (pyridin-2-yl-methyl) -1, 1-bis (pyrazol-1-yl) -2-phenyl- 1-aminoethane; N, N-bis (pyridin-2-yl-methyl) -1, 1-bis (imidazol-2-yl) -1- aminoethane; N, N-bis (pyridin-2-yl-methyl) -1, 1-bis (imidazol-2-yl) -2- phenyl-1-aminoethane; N, N-bis (pyridin-2-yl-methyl) -1, 1-bis (1, 2, 4-triazol-l-yl) -1- aminoethane; N, N-bis (pyridin-2-yl-methyl) -1, 1-bis (1,2, 4-triazol-l-yl) -1- aminoethane; N, N-bis (pyridin-2-yl-methyl ) -1, 1-bis (pyridin-2-yl) -1- aminoethane; N, N-bis (pyridin-2-yl-methyl) -1, 1-bis (pyridin-2-yl) -1- aminohexane; N, N-bis (pyridin-2-yl-methyl) -1, 1-bis (pyridin-2-yl) -2-phenyl- 1-aminoethane; N, N-bis (pyridin-2-yl-methyl) -1, 1-bis (pyridin-2-yl) -2- (4- sulphonic acid-phenyl) -1-aminoethane; N, N-bis (pyridin-2-yl-methyl) -1, 1-bis (pyridin-2-yl) -2- (pyridin-2-yl) -1-aminoethane; N, N-bis (pyridin-2-yl-methyl) -1, 1-bis (pyridin-2-yl) -2- (pyridin-3-yl) -1-aminoethane; N, N-bis (pyridin-2-yl-methyl) -1, 1-bis (pyridin-2-yl) -2- (pyridin-4-yl) -1-aminoethane; N, N-bis (pyridin-2-yl-methyl) -1, 1-bis (pyridin-2-yl) -2- (1- alkyl-pyridinium-4-yl) -1-aminoethane; N, N-bis (pyridin-2-yl-methyl) -1, 1-bis (pyridin-2-yl) -2- (1- alkyl-pyridinium-3-yl) -1-aminoethane; N, N-bis (pyridin-2-yl-methyl) -1, 1-bis (pyridin-2-yl) -2- (1- alkyl-pyridinium-2-yl) -1-aminoethane; (ii) 2-amino-ethyl containing ligands such as: N, N-bis (2- (N-alkyl) amino-ethyl) -bis (pyridin-2- yl) methylamine; N, N-bis (2- (N-alkyl) amino-ethyl) -bis (pyrazol-1- yl) methylamine; N, N-bis (2- (N-alkyl) amino-ethyl) -bis (imidazol-2- yl) methylamine; N, N-bis (2- (N-alkyl) amino-ethyl) -bis (1,2, 4-triazol-l- yl ) methylamine ; N, N-bis (2- (N, N-dialkyl) amino-ethyl) -bis (pyridin-2- yl) methylamine; N, N-bis (2- (N, N-dialkyl) amino-ethyl) -bis (pyrazol-1- yl ) methylamine ; N, N-bis (2- (N, N-dialkyl) amino-ethyl) -bis (imidazol-2- yl) methylamine; N, N-bis (2- (N, -dialkyl) amino-ethyl) -bis ( 1, 2, 4-triazol-l- yl ) methylamine; N, N-bis (pyridin-2-yl-methyl) -bis (2-amino-ethyl) methylamine; N, N-bis (pyrazol-1-yl-methyl) -bis (2-amino-ethyl) methylamine; N, N-bis (imidazol-2-yl-methyl) -bis (2-amino-ethyl) methylamine; N, N-bis (1,2, 4-triazol-l-yl-methyl) -bis (2-aminoethyl ) methylamine . More preferred ligands are: N, N-bis (pyridin-2-yl-methyl) -bis (pyridin-2-yl)methylamine, hereafter referred to as N4Py. N, N-bis (pyridin-2-yl-methyl) -1, 1-bis (pyridin-2-yl) -1- aminoethane, hereafter referred to as MeN4Py, N, N-bis (pyridin-2-yl-methyl) -1, 1-bis (pyridin-2-yl) -2-phenyl- 1-aminoethane, hereafter referred to as BzN4Py. In a fifth embodiment of the second variant, the ligand represents a pentadentate or hexadentate ligand of general formula (VE) : R^N-W-NRV (VE) wherein each R 1 independently represents -R 3 -V, in which R 3 represents optionally substituted alkylene, alkenylene, oxyalkylene, aminoalkylene or alkylene ether, and V represents an optionally substituted heteroaryl group selected from pyridinyl, pyrazinyl, pyrazolyl, pyrrolyl, imidazolyl, benzimidazolyl, pyrimidinyl, triazolyl and thiazolyl; - 4 1 represents an optionally substituted alkylene bridging group selected from —CH 2 CH2—, —CHCH 2 CH— , —CH2CH 2 CH 2 CH 2 — , —CH —CgH —CH 2 — , —CH2—CgHio- CH 2 -, and -CH 2 -CιoH 5 -CH 2 -; and R 2 represents a group selected from R 1 , and alkyl, aryl and arylalkyl groups optionally substituted with a substituent selected from hydroxy, alkoxy, phenoxy, carboxylate, carboxamide, carboxylic ester, sulphonate, amine, alkylamine and N + (R 4 ) 3 , wherem R 4 is selected from hydrogen, alkanyl, alkenyl, arylalkanyl, arylalkenyl, oxyalkanyl, oxyalkenyl, aminoalkanyl, aminoalkenyl, alkanyl ether and alkenyl ether. The ligand having the general formula (VE) , as defined above, is a pentadentate ligand or, if R 1= R 2 , can be a hexadentate ligand. As mentioned above, by pentadentate' is meant that five hetero atoms can coordinate to the metal M ion in the metal-complex. Similarly, by hexadentate' is meant that six hetero atoms can principle coordinate to the metal M ion. However, in this case it is believed that one of the arms will not be bound in the complex, so that the hexadentate ligand will be penta coordinating. In the formula (VE) , two hetero atoms are linked by the bridging group and one coordinating hetero atom is contained in each of the three R 1 groups. Preferably, the coordinating hetero atoms are nitrogen atoms. The ligand of formula (VE) comprises at least one optionally substituted heteroaryl group in each of the three R 1 groups. Preferably, the heteroaryl group is a pyridin-2-yl group, in particular a methyl- or ethyl-substituted pyridin-2-yl group. The heteroaryl group is linked to an N atom in formula (VE) , preferably via an alkylene group, more preferably a methylene group. Most preferably, the heteroaryl group is a 3-methyl-pyridin-2-yl group linked to an N atom via methylene. The group R 2 in formula (VE) is a substituted or unsubstituted alkyl, aryl or arylalkyl group, or a group R 1 . However, preferably R 2 is different from each of the groups X in the formula above. Preferably, R 2 is methyl, ethyl, benzyl, 2-hydroxyethyl or 2-methoxyethyl. More preferably, R 2 is methyl or ethyl. The bridging group W may be a substituted or unsubstituted alkylene group selected from -CH 2 CH 2 -, -CH 2 CH 2 CH 2 -, -CH 2 CH 2 CH- 2 CH 2 -, -CH 2 -C 6 H 4 -CH 2 -, -CH 2 -C 6 Hιo-CH 2 -, and -CH 2 -C 10 H 6 -CH 2 - (wherein -CeH 4 -, -CβHio- -CioH δ - can be ortho- , para- , or ιrιeta-C6H 4 -, -CβHio-, -CioHβ-) . Preferably, the bridging group is an ethylene or 1,4-butylene group, more preferably an ethylene group. Preferably, V represents substituted pyridin-2-yl, especially methyl-substituted or ethyl-substituted pyridin- 2-yl, and most preferably V represents 3-methyl pyridin-2- yi. (F) Ligands of the classes disclosed in O-A-98/39098 and O-A-98/39406. The counter ions Y in formula (Al) balance the charge z on the complex formed by the ligand L, metal M and coordinating species X. Thus, if the charge z is positive, Y may be an anion such as RCOO " , BPh 4 ~ , C10 4 " , BF 4 ~ , PF 6 " , RS0 3 " , RS0 4 ~ , S0 4 2" , N0 3 "" , F ~ , Cl " , Br " , or I " , with R being hydrogen, optionally substituted alkyl or optionally substituted aryl. If z is negative, Y may be a common cation such as an alkali metal, alkaline earth metal or (alkyl) ammonium cation. Suitable counter ions Y include those which give rise to the formation of storage-stable solids. Preferred counter ions for the preferred metal complexes are selected from R 7 COO " , C10 4 " , BF 4 " , PF 6 " , RSO 3 " (in particular CF 3 S0 3 " ) , RS0 4 ~ , S0 4 2~ , N0 3 ~ , F " , Cl " , Br " , and I " , wherein R represents hydrogen or optionally substituted phenyl, naphthyl or Cχ-C 4 alkyl. It will be appreciated that the complex (Al) can be formed by any appropriate means, including in si tu formation whereby precursors of the complex are transformed into the active complex of general formula (Al) under conditions of storage or use. Preferably, the complex is formed as a well-defined complex or in a solvent mixture comprising a salt of the metal M and the ligand L or ligand L-generating species. Alternatively, the catalyst may be formed in si tu from suitable precursors for the complex, for example in a solution or dispersion containing the precursor materials. In one such example, the active catalyst may be formed in si tu in a mixture comprising a salt of the metal M and the ligand L, or a ligand L-generating species, in a suitable solvent. Thus, for example, if M is iron, an iron salt such as FeS0 4 can be mixed in solution with the ligand L, or a ligand L-generatmg species, to form the active complex. Thus, for example, the composition may formed from a mixture of the ligand L and a metal salt MX n in which preferably n=l- 5, more preferably 1-3. In another such example, the ligand L, or a ligand L-generatmg species, can be mixed with metal M ions present in the substrate or wash liquor to form the active catalyst m si tu . Suitable ligand L-generatmg species include metal-free compounds or metal coordination complexes that comprise the ligand L and can be substituted by metal M ions to form the active complex according the formula (Al) . In typical washing compositions the level of the catalyst is such that the m-use level is from 0.05μM to 50mM, with preferred m-use levels for domestic laundry operations falling in the range 0.5 μM to 100 μM, more preferably from 1 μM to 10 μM. Preferably, the composition provides a pH in the range from pH 6 to 13, more preferably from pH 6 to 11, still more preferably from pH 8 to 11, and most preferably from pH 8 to 10, in particular from pH 9 to 10. In the context of the present invention bleaching should be understood as relating generally to the decolourisation of stains or of other materials attached to or associated with a substrate. However, it is envisaged that the present invention can be applied where a requirement is the removal and/or neutralisation by an oxidative bleaching reaction of malodours or other undesirable components attached to or otherwise associated with a substrate. Furthermore, in the context of the present invention bleaching is to be understood as being restricted to any bleaching mechanism or process that does not require the presence of light or activation by light. Thus, photobleaching compositions and processes relying on the use of photobleach catalysts or photobleach activators and the presence of light are excluded from the present invention. The present invention has particular application in detergent bleaching, especially for laundry cleaning. Accordingly, the composition preferably contains a surface- active material, optionally together with detergency builder . The composition may contain a surface-active material in an amount, for example, of from 10 to 50% by weight. The surface-active material may be naturally derived, such as soap, or a synthetic material selected from anionic, nonionic, amphoteric, zwitterionic, cationic actives and mixtures thereof. Many suitable actives are commercially available and are fully described in the literature, for example in "Surface Active Agents and Detergents", Volumes I and II, by Schwartz, Perry and Berch. Typical synthetic anionic surface-actives are usually water- soluble alkali metal salts of organic sulphates and sulphonates having alkyl groups containing from about 8 to about 22 carbon atoms, the term "alkyl" being used to include the alkyl portion of higher aryl groups. Examples of suitable synthetic anionic detergent compounds are sodium and ammonium alkyl sulphates, especially those obtained by sulphating higher (Cg-Ciβ) alcohols produced, for example, from tallow or coconut oil; sodium and ammonium alkyl (Cg- C 20 ) benzene sulphonates, particularly sodium linear secondary alkyl (C10-C 15 ) benzene sulphonates; sodium alkyl glyceryl ether sulphates, especially those ethers of the higher alcohols derived from tallow or coconut oil fatty acid monoglyceride sulphates and sulphonates; sodium and ammonium salts of sulphuric acid esters of higher (Cg-Ciβ) fatty alcohol alkylene oxide, particularly ethylene oxide, reaction products; the reaction products of fatty acids such as coconut fatty acids esterified with isethionic acid and neutralised with sodium hydroxide; sodium and ammonium salts of fatty acid amides of methyl taurine; alkane monosulphonates such as those derived by reacting alpha- olefins (C 8 -C2o) with sodium bisulphite and those derived by reacting paraffins with S0 2 and Cl 2 and then hydrolysing with a base to produce a random sulphonate; sodium and ammonium (C7-C 12 ) dialkyl sulphosuccinates; and olefin sulphonates, which term is used to describe material made by reacting olefins, particularly (Cι 0 -C 2 o) alpha-olefins, with S0 3 and then neutralising and hydrolysing the reaction product. The preferred anionic detergent compounds are sodium (Cι 0 -Cι 5 ) alkylbenzene sulphonates, and sodium (Ciε-Cis) alkyl ether sulphates. Examples of suitable nonionic surface-active compounds which may be used, preferably together with the anionic surface- active compounds, include, in particular, the reaction products of alkylene oxides, usually ethylene oxide, with alkyl (C6-C22) phenols, generally 5-25 EO, i.e. 5-25 units of ethylene oxides per molecule; and the condensation products of aliphatic (C 8 -Cι 8 ) primary or secondary linear or branched alcohols with ethylene oxide, generally 2-30 EO. Other so- called nonionic surface-actives include alkyl polyglycosides, sugar esters, long-chain tertiary amine oxides, long-chain tertiary phosphine oxides and dialkyl sulphoxides . Amphoteric or zwitterionic surface-active compounds can also be used in the compositions of the invention but this is not normally desired owing to their relatively high cost. If any amphoteric or zwitterionic detergent compounds are used, it is generally in small amounts in compositions based on the much more commonly used synthetic anionic and nonionic actives. The composition will preferably comprise from 1 to 15 % wt of anionic surfactant and from 10 to 40 % by weight of nonionic surfactant. In a further preferred embodiment, the detergent active system is free from Cι 6 -Cι 2 fatty acid soaps. The composition may also contain a detergency builder, for example in an amount of from about 5 to 80 % by weight, preferably from about 10 to 60 % by weight. Builder materials may be selected from 1) calcium sequestrant materials, 2) precipitating materials, 3) calcium ion-exchange materials and 4) mixtures thereof. Examples of calcium sequestrant builder materials include alkali metal polyphosphates, such as sodium tripolyphosphate; nitrilotriacetic acid and its water- soluble salts; the alkali metal salts of carboxymethyloxy succinic acid, ethylene diamine tetraacetic acid, oxydisuccinic acid, mellitic acid, benzene polycarboxylic acids, citric acid; and polyacetal carboxylates as disclosed in US-A-4, 144,226 and US-A-4 , 146, 495. Examples of precipitating builder materials include sodium orthophosphate and sodium carbonate. Examples of calcium ion-exchange builder materials include the various types of water-insoluble crystalline or amorphous aluminosilicates, of which zeolites are the best known representatives, e.g. zeolite A, zeolite B (also known as zeolite P) , zeolite C, zeolite X, zeolite Y and also the zeolite P-type as described in EP-A-0, 384 , 070. In particular, the composition may contain any one of the organic and inorganic builder materials, though, for environmental reasons, phosphate builders are preferably omitted or only used in very small amounts. Typical builders usable in the present invention are, for example, sodium carbonate, calcite/carbonate, the sodium salt of nitrilotriacetic acid, sodium citrate, carboxymethyloxy malonate, carboxymethyloxy succinate and water-insoluble crystalline or amorphous aluminosilicate builder materials, each of which can be used as the main builder, either alone or in admixture with minor amounts of other builders or polymers as co-builder. It is preferred that the composition contains not more than 5% by weight of a carbonate builder, expressed as sodium carbonate, more preferably not more than 2.5 % by weight to substantially nil, if the composition pH lies in the lower alkaline region of up to 10. Apart from the components already mentioned, the composition can contain any of the conventional additives m amounts of which such materials are normally employed in fabric washing detergent compositions. Examples of these additives include buffers such as carbonates, lather boosters, such as alkanolamides, particularly the monoethanol amides derived from palmkernel fatty acids and coconut fatty acids; lather depressants, such as alkyl phosphates and silicones; anti- redeposition agents, such as sodium carboxymethyl cellulose and alkyl or substituted alkyl cellulose ethers; stabilisers, such as phosphonic acid derivatives (i.e. Dequest® types) ; fabric softening agents; inorganic salts and alkaline buffering agents, such as sodium sulphate and sodium silicate; and, usually in very small amounts, fluorescent agents; perfumes; enzymes, such as proteases, cellulases, lipases, amylases and oxidases; germicides and colourants . Transition metal sequestrants such as EDTA, and phosphonic acid derivatives such as EDTMP (ethylene diamine tetra (methylene phosphonate) ) may also be included, in addition to the ligand specified, for example to improve the stability sensitive ingredients such as enzymes, fluorescent agents and perfumes, but provided the composition remains bleaching effective. However, the composition according to the present invention containing the ligand, is preferably substantially, and more preferably completely, devoid of transition metal sequestrants (other than the ligand) . Whilst the present invention is based on the catalytic bleaching of a substrate by atmospheric oxygen or air, it will be appreciated that small amounts of hydrogen peroxide or peroxy-based or -generating systems may be included in the composition, if desired. Therefore, by "substantially devoid of peroxygen bleach or peroxy-based or -generating bleach systems" is meant that the composition contains from 0 to 50 %, preferably from 0 to 10 %, more preferably from 0 to 5 %, and optimally from 0 to 2 % by molar weight on an oxygen basis, of peroxygen bleach or peroxy-based or - generating bleach systems. Preferably, however, the composition will be wholly devoid of peroxygen bleach or peroxy-based or -generating bleach systems. Thus, at least 10 %, preferably at least 50 % and optimally at least 90 % of any bleaching of the substrate is effected by oxygen sourced from the air. Throughout the description and claims generic groups have been used, for example alkyl, alkoxy, aryl. Unless otherwise specified the following are preferred group restrictions that may be applied to generic groups found within compounds disclosed herein: alkyl: linear and branched Cl-C8-alkyl, alkenyl: C2-C6-alkenyl, cycloalkyl: C3-C8-cycloalkyl, alkoxy: Cl-C6-alkoxy, alkylene: selected from the group consisting of: methylene; 1, 1-ethylene; 1, 2-ethylene; 1, 1-propylidene; 1, 2-propylene; 1, 3-propylene; 2, 2-propylidene; butan-2-ol-l, 4-diyl; propan- 2-ol-l, 3-diyl; 1,4-butylene; cyclohexane-1, 1-diyl; cyclohexan-1, 2-diyl; cyclohexan-1, 3-diyl; cyclohexan-1, 4- diyl; cyclopentane-1, 1-diyl ; cyclopentan-1, 2-diyl; and cyclopentan-1, 3-diyl, aryl: selected from homoaromatic compounds having a molecular weight under 300, arylene: selected from the group consisting of: 1,2- phenylene; 1, 3-phenylene; 1, 4-phenylene; 1, 2-naphtalenylene; 1, 3-naphtalenylene; 1, 4-naphtalenylene; 2, 3-naphtalenylene; l-hydroxy-2, 3-phenylene; l-hydroxy-2, 4-phenylene; 1-hydroxy- 2, 5-phenylene; and l-hydroxy-2, 6-phenylene, heteroaryl: selected from the group consisting of: pyridinyl; pyrimidinyl; pyrazinyl; triazolyl; pyridazinyl; 1, 3, 5-triazinyl; quinolinyl; isoquinolinyl; quinoxalinyl; imidazolyl; pyrazolyl; benzimidazolyl; thiazolyl; oxazolidinyl; pyrrolyl; carbazolyl; indolyl; and isoindolyl, wherein the heteroaryl may be connected to the compound via any atom in the ring of the selected heteroaryl, heteroarylene: selected from the group consisting of: pyridindiyl; quinolindiyl; pyrazodiyl; pyrazoldiyl; triazolediyl; pyrazindiyl; and imidazolediyl, wherein the heteroarylene acts as a bridge in the compound via any atom in the ring of the selected heteroarylene, more specifically preferred are: pyridin-2, 3-diyl; pyridin-2, 4-diyl; pyridin- 2,5-diyl; pyridin-2, 6-diyl; pyridin-3, 4-diyl; pyridin-3,5- diyl; quinolin-2, 3-diyl; quinolin-2, 4-diyl; quinolin-2, 8- diyl; isoquinolin-1, 3-diyl; isoquinolin-1, 4-diyl; pyrazol- 1, 3-diyl; pyrazol-3, 5-diyl; triazole-3, 5-diyl; triazole-1, 3- diyl; pyrazin-2, 5-diyl; and imidazole-2, 4-diyl, heterocycloalkyl: selected from the group consisting of: pyrrolinyl; pyrrolidinyl; morpholinyl; piperidinyl; piperazinyl; hexamethylene imine; 1, 4-piperazinyl; tetrahydrothiophenyl; tetrahydrofuranyl; 1,4,7- triazacyclononanyl; 1,4,8, 11-tetraazacyclotetradecanyl; 1,4,7,10, 13-pentaazacyclopentadecanyl; 1, 4-diaza-7-thia- cyclononanyl; 1, 4-diaza-7-oxa-cyclononanyl; 1,4,7,10- tetraazacyclododecanyl; 1, 4-dioxanyl; 1, 4, 7-trithia- cyclononanyl; tetrahydropyranyl; and oxazolidinyl, wherein the heterocycloalkyl may be connected to the compound via any atom in the ring of the selected heterocycloalkyl, heterocycloalkylene: selected from the group consisting of: piperidin-1, 2-ylene; piperidin-2, 6-ylene; piperidin-4, 4- ylidene; 1, 4-piperazin-l, 4-ylene; 1, 4-piperazin-2, 3-ylene; 1, 4-piperazin-2, 5-ylene; 1, 4-piperazin-2, 6-ylene; 1,4- piperazin-1, 2-ylene; 1, 4-piperazin-l, 3-ylene; 1, 4-piperazin- 1,4-ylene; tetrahydrothiophen-2, 5-ylene; tetrahydrothiophen- 3, 4-ylene; tetrahydrothiophen-2, 3-ylene; tetrahydrofuran- 2, 5-ylene; tetrahydrofuran-3, -ylene; tetrahydrofuran-2, 3- ylene; pyrrolidin-2, 5-ylene; pyrrolidin-3, 4-ylene; pyrrolidin-2, 3-ylene; pyrrolidin-1, 2-ylene; pyrrolidin-1, 3- ylene; pyrrolidin-2, 2-ylidene; 1, 4 , 7-triazacyclonon-l, 4- ylene; 1, 4 , 7-triazacyclonon-2, 3-ylene; 1, 4 , 7-triazacyclonon- 2,9-ylene; 1, 4 , 7-triazacyclonon-3, 8-ylene; 1,4,7- triazacyclonon-2, 2-ylidene; 1,4,8, 11-tetraazacyclotetradec- 1, 4-ylene; 1,4,8, 11-tetraazacyclotetradec-l, 8-ylene; 1,4,8, ll-tetraazacyclotetradec-2, 3-ylene; 1,4,8,11- tetraazacyclotetradec-2, 5-ylene; 1,4, 8, 11- tetraazacyclotetradec-l, 2-ylene; 1,4,8, ll- tetraazacyclotetradec-2, 2-ylidene; 1,4,7,10- tetraazacyclododec-1, 4-ylene; 1,4,7, 10-tetraazacyclododec- 1,7-ylene; 1, 4, 7, 10-tetraazacyclododec-l, 2-ylene; 1,4,7,10- tetraazacyclododec-2, 3-ylene; 1, 4 , 7, 10-tetraazacyclododec- 2, 2-ylidene; 1,4,7,10, 13-pentaazacyclopentadec-l, 4-ylene; 1,4,7,10, 13-pentaazacyclopentadec-l, 7-ylene; 1,4,7,10,13- pentaazacyclopentadec-2, 3-ylene; 1,4, 7, 10, 13- pentaazacyclopentadec-l, 2-ylene; 1,4,7,10,13- pentaazacyclopentadec-2 , 2-ylidene; 1, 4-diaza-7-thia- cyclonon-1, 4-ylene; 1, 4-diaza-7-thia-cyclonon-l, 2-ylene; 1, -diaza-7-thia-cyclonon-2, 3-ylene; 1, 4-diaza-7-thia- cyclonon-6, 8-ylene; 1, 4-diaza-7-thia-cyclonon-2, 2-ylidene; 1, 4-diaza-7-oxa-cyclonon-l, 4-ylene; 1, 4-diaza-7-oxa- cyclonon-1, 2-ylene; 1, 4-diaza-7-oxa-cyclonon-2, 3-ylene; 1,4- diaza-7-oxa-cyclonon-6, 8-ylene; 1, 4-diaza-7-oxa-cyclonon- 2, 2-ylidene; 1, 4-dioxan-2, 3-ylene; 1, 4-dioxan-2, 6-ylene; 1, 4-dioxan-2, 2-ylidene; tetrahydropyran-2, 3-ylene; tetrahydropyran-2, 6-ylene; tetrahydropyran-2, 5-ylene; tetrahydropyran-2, 2-ylidene; 1, 4, 7-trithia-cyclonon-2, 3- ylene; 1, 4 , 7-trithia-cyclonon-2, 9-ylene; and 1, 4 , 7-trithia- cyclonon-2 , 2-ylidene, amine: the group -N(R) 2 where each R is independently selected from: hydrogen; Cl-C6-alkyl; Cl-C6-alkyl-C6H5; and phenyl, wherein when both R are Cl-C6-alkyl both R together may form an -NC3 to an -NC5 heterocyclic ring with any remaining alkyl chain forming an alkyl substituent to the heterocyclic ring, halogen: selected from the group consisting of: F; Cl; Br and I, sulfonate: the group -S(0) 2 0R, wherein R is selected from: hydrogen; Cl-C6-alkyl; phenyl; Cl-C6-alkyl-C6H5; Li; Na; K; Cs; Mg; and Ca, sulfate: the group -OS(0) 2 OR, wherein R is selected from: hydrogen; Cl-C6-alkyl; phenyl; Cl-C6-alkyl-C6H5; Li; Na; K; Cs; Mg; and Ca, sulfone: the group -S(0) 2 R, wherein R is selected from: hydrogen; Cl-C6-alkyl; phenyl; Cl-C6-alkyl-C6H5 and amine (to give sulfonamide) selected from the group: -NR'2, wherein each R' is independently selected from: hydrogen; Cl-C6-alkyl; Cl-C6-alkyl-C6H5; and phenyl, wherein when both R' are Cl-C6-alkyl both R' together may form an -NC3 to an - NC5 heterocyclic ring with any remaining alkyl chain forming an alkyl substituent to the heterocyclic ring, carboxylate derivative: the group -C(0)OR, wherein R is selected from: hydrogen; Cl-C6-alkyl; phenyl; Cl-C6-alkyl- C6H5; Li; Na; K; Cs; Mg; and Ca, carbonyl derivative: the group -C(0)R, wherein R is selected from: hydrogen; Cl-C6-alkyl; phenyl; Cl-C6-alkyl- C6H5 and amine (to give amide) selected from the group: - NR'2, wherein each R' is independently selected from: hydrogen; Cl-C6-alkyl; Cl-C6-alkyl-C6H5; and phenyl, wherein when both R' are Cl-C6-alkyl both R' together may form an - NC3 to an -NC5 heterocyclic ring with any remaining alkyl chain forming an alkyl substituent to the heterocyclic ring, phosphonate: the group -P(O) (OR) 2 , wherein each R is independently selected from: hydrogen; Cl-C6-alkyl; phenyl; Cl-C6-alkyl-C6H5; Li; Na; K; Cs; Mg; and Ca, phosphate: the group -0P(0) (OR) 2 , wherein each R is independently selected from: hydrogen; Cl-C6-alkyl; phenyl; Cl-C6-alkyl-C6H5; Li; Na; K; Cs; Mg; and Ca, phosphine: the group -P(R) 2 , wherein each R is independently selected from: hydrogen; Cl-C6-alkyl; phenyl; and Cl-C6-alkyl-C6H5, phosphine oxide: the group -P(0)R 2 , wherein R is independently selected from: hydrogen; Cl-C6-alkyl; phenyl; and Cl-C6-alkyl-C6H5; and amine (to give phosphonamidate) selected from the group: -NR'2, wherein each R 1 is independently selected from: hydrogen; Cl-C6-alkyl; C1-C6- alkyl-C6H5; and phenyl, wherein when both R' are Cl-C6-alkyl both R' together may form an -NC3 to an -NC5 heterocyclic ring with any remaining alkyl chain forming an alkyl substituent to the heterocyclic ring. Unless otherwise specified the following are more preferred group restrictions that may be applied to groups found within compounds disclosed herein: alkyl: linear and branched Cl-C6-alkyl, alkenyl: C3-C6-alkenyl, cycloalkyl: C6-C8-cycloalkyl, alkoxy: Cl-C4-alkoxy, alkylene: selected from the group consisting of: methylene; 1, 2-ethylene; 1, 3-propylene; butan-2-ol-l, 4-diyl; 1,4- butylene; cyclohexane-1, 1-diyl; cyclohexan-1, 2-diyl; cyclohexan-1, 4-diyl; cyclopentane-1, 1-diyl; and cyclopentan- 1, 2-diyl, aryl: selected from group consisting of: phenyl; biphenyl; naphthalenyl; anthracenyl; and phenanthrenyl, arylene: selected from the group consisting of: 1,2- phenylene; 1, 3-phenylene; 1, 4-phenylene; 1, 2-naphtalenylene; 1, 4-naphtalenylene; 2, 3-naphtalenylene and l-hydroxy-2, 6- phenylene, heteroaryl: selected from the group consisting of: pyridinyl; pyrimidinyl; quinolinyl; pyrazolyl; triazolyl; isoquinolinyl; imidazolyl; and oxazolidinyl, wherein the heteroaryl may be connected to the compound via any atom in the ring of the selected heteroaryl, heteroarylene: selected from the group consisting of: pyridin-2, 3-diyl; pyridin-2, 4-diyl; pyridin-2, 6-diyl; pyridin-3, 5-diyl; quinolin-2, 3-diyl; quinolin-2 , -diyl; isoquinolin-1, 3-diyl; isoquinolin-1, 4-diyl; pyrazol-3,5- diyl; and imidazole-2 , 4-diyl, heterocycloalkyl: selected from the group consisting of: pyrrolidinyl; morpholinyl; piperidinyl; piperidinyl; 1,4- piperazinyl; tetrahydrofuranyl; 1, 4 , 7-triazacyclononanyl; 1,4,8, 11-tetraazacyclotetradecanyl; 1,4,7,10,13- pentaazacyclopentadecanyl; 1,4,7, 10-tetraazacyclododecanyl; and piperazinyl, wherein the heterocycloalkyl may be connected to the compound via any atom in the ring of the selected heterocycloalkyl, heterocycloalkylene: selected from the group consisting of: piperidin-2, 6-ylene; piperidin-4, 4-ylidene; 1,4- piperazin-1, 4-ylene; 1, 4-piperazin-2 , 3-ylene; 1, 4-piperazin- 2, 6-ylene; tetrahydrothiophen-2, 5-ylene; tetrahydrothiophen- 3, 4-ylene; tetrahydrofuran-2, 5-ylene; tetrahydrofuran-3, 4- ylene; pyrrolidin-2, 5-ylene; pyrrolidin-2, 2-ylidene; 1,4,7- triazacyclonon-1, 4-ylene; 1,4, 7-triazacyclonon-2, 3-ylene; 1,4, 7-triazacyclonon-2, 2-ylidene; 1,4,8,11- tetraazacyclotetradec-1, 4-ylene; 1,4, 8, 11- tetraazacyclotetradec-l, 8-ylene; 1,4,8, ll-tetraazacyclotetradec-2, 3-ylene; 1, 4, 8 , ll- tetraazacyclotetradec-2, 2-ylidene; 1,4,7, 10-tetraazacyclododec-l, 4-ylene; 1,4,7,10- tetraazacyclododec-1, 7-ylene; 1, 4 , 7, 10-tetraazacyclododec-2 , 3-ylene; 1,4,7,10- tetraazacyclododec-2, 2-ylidene; 1,4, 7, 10, 13- pentaazacyclopentadec-l, 4-ylene; 1,4, 7, 10, 13- pentaazacyclopentadec-l, 7-ylene; 1, 4-diaza-7-thia-cyclonon- 1, 4-ylene; 1, 4-diaza-7-thia-cyclonon-2, 3-ylene; l,4-diaza-7- thia-cyclonon-2, 2-ylidene; 1, 4-diaza-7-oxa-cyclonon-l, 4- ylene; 1, 4-diaza-7-oxa-cyclonon-2, 3-ylene; 1, 4-diaza-7-oxa- cyclonon-2, 2-ylidene; 1, 4-dioxan-2, 6-ylene; 1, 4-dioxan-2, 2- ylidene; tetrahydropyran-2, 6-ylene; tetrahydropyran-2, 5- ylene; and tetrahydropyran-2, 2-ylidene, amine: the group -N(R) , wherein each R is independently selected from: hydrogen; Cl-C6-alkyl; and benzyl, halogen: selected from the group consisting of: F and Cl, sulfonate: the group -S(0) 2 OR, wherein R is selected from: hydrogen; Cl-C6-alkyl; Na; K; Mg; and Ca, sulfate: the group -OS(0) 2 θR, wherein R is selected from: hydrogen; Cl-C6-alkyl; Na; K; Mg; and Ca, sulfone: the group -S(0) 2 R, wherein R is selected from: hydrogen; Cl-C6-alkyl; benzyl and amine selected from the group: -NR'2, wherein each R' is independently selected from: hydrogen; Cl-C6-alkyl; and benzyl, carboxylate derivative: the group -C(0)OR, wherein R is selected from hydrogen; Na; K; Mg; Ca; Cl-C6-alkyl; and benzyl, carbonyl derivative: the group: -C(0)R, wherein R is selected from: hydrogen; Cl-C6-alkyl; benzyl and amine selected from the group: -NR'2, wherein each R' is independently selected from: hydrogen; Cl-C6-alkyl; and benzyl, phosphonate: the group -P(O) (OR) 2 , wherein each R is independently selected from: hydrogen; Cl-C6-alkyl; benzyl; Na; K; Mg; and Ca, phosphate: the group -OP(O) (OR) 2 , wherein each R is independently selected from: hydrogen; Cl-C6-alkyl; benzyl; Na; K; Mg; and Ca, phosphine: the group -P(R) 2 , wherein each R is independently selected from: hydrogen; Cl-C6-alkyl; and benzyl, phosphine oxide: the group -P(0)R 2 , wherein R is independently selected from: hydrogen; Cl-C6-alkyl; benzyl and amine selected from the group: -NR'2, wherein each R' is independently selected from: hydrogen; Cl-C6-alkyl; and benzyl . The present invention will now be further illustrated by the following non-limiting examples: EXAMPLES Example 1 (Tergotometer tests: bleach performance and dye fading) : Multi wash experiments wre carried out in a tergotometer. Three formulations (Products "A", " B" and "C") were tested, having the compositions shown below. In Product "A", the catalyst was delivered as 50 ml stock solution containing 0.0346g in 1 litre of demineralised water. (*)The composition of the detergent base in each case was as follows: (**) sodium silicate/sodium carbonate co-granulate (30% sodium silicate) (***) sodium carboxymethylcellulose, 69% active The wash conditions used were: Wash temperature: 50°C Wash time: 30 minutes Wash volume: 500ml (demineralised water) Agitator speed: lOOrpm Each wash contained 4 cotton swatches dyed with 8% Remazol Black B dye (total of 8g cloth) . These cloths were washed sequentially in 20 repeat washes, each time using the same formulation. Periodically, a bleach performance monitor (tomato stain) was added additionally to the tergotometer pot to check bleach performance. Fresh tomato stains were used for each of these performance checks. The tomato stain bleach monitors were prepared as follows: To prepare s tain : - Place 5g of soya oil (ex Brazil) and 95gms Pomarola sauce (ex Brazil) in a 250ml glass beaker. Mix and heat in the microwave on full power for 1 minute. Sieve the hot mix through a tea strainer and allow to cool to <50°C before applying. For small 5cm stains : -Place the fabric to be stained into the template. Apply 0.5mls of the tomato mix using a disposable syringe. Spread the stain using a brush. The stains are placed on to the non absorbent side of greaseproof (waxy) paper sheet and placed within a drying cabinet where they are dried for 4 days in the dark, with vents left open to ensure good air circulation. The bleach performance (removal of tomato stain) of the three formulations, averaged from 5 washes, is shown in Table 1 below. The results are quoted as ΔE values, representing residual stain relative to clean white cloth. Also shown in Table 1 is the extent of dye fading following 20 repeat washes in each of the formulations, relative to the original unwashed fabrics. Table 1 From the results in Table 1, it may be seen that formulation A gave superior stain removal compared to formulations B and C, whilst producing similar dye fading to a bleach-free formulation (C) , and less dye fading than the conventional TAED/percarbonate bleach system (B) . Therefore, formulation A according to the invention gives better stain removal then a conventional bleach (B) whilst also providing reduced dye fading. Example 2 (Machine wash tests: dye fading): Two formulations (Products "E" and " F" ) were tested, having the following compositions: (*)The composition of the detergent base in each case was ollows: (**) sodium silicate/sodium carbonate co-granulate (30% sodium silicate) (***) sodium carboxymethylcellulose, 69% active Wash Conditions: A single replicate of 40 wash cycles using wash loads containing the commercial articles and enough desized cotton ballast to increase the weight of the load to 2.5kg, and four washing machines. Machine Miele W756 Wash cycle as recommended Water hardness 24 degrees FH Intake volume 14.5 litres Intake temp ambient Load monitors (+ ballast to make 2.5kg) Dispensing powder delivered via a scuttle - catalyst by addition to the water intake through the dispenser drawer after dispensing m 50ml water. The articles were split into two loads (40°C and 50°C) according to the retailer's recommended wash conditions for each garment. Rotation across machines was on a daily basis, with one complete day's washing per machine per test product followed by rotation. On completion of each day's washes, the machines were taken through a 60°C wash with the control product, dosed at 50g, without any load, and the dispenser was cleaned out. Ballast loads were only used with the same test product and tumble dried for overnight storage. Dye fading The following tables show the levels of dye fading observed m the above multi-wash experiments for a series of article purchased from clothing retailers in the UK. A single dyed test cloth (8% Remazol Black B on woven cotton) was also included in both 40 and 50 °C studies. In each case, dye fading is expressed m terms of colour change from the original unwashed article (ΔE) following 40 wash cycles. A larger value of ΔE indicates a larger colour change from the original and hence a more faded dye. Tables 2 and 3 below show the dye fading observed after 40 wash cycles for each product (E,F): Table 2 Table 3 From the results in Tables 2 and 3, it may be seen that the current TAED/percarbonate bleach system (F) gives more dye fading than the catalyst/air product (E) . Example 3: The following compounds were prepared and tested in regard to their dye-fading activity. (i) Preparation of MeN4Py ligand N, N-bis (pyridin-2-yl-methyl) -1, 1-bis (pyridin-2-yl) -1- aminoethane, MeN4Py, was prepared according to the procedure found in EP 0 909 809 A. [ii) Synthesis of the complex FeMeN4PyCl 2 (complex 1] MeN4Py ligand (33.7 g; 88.5mmoles) was dissolved m 500ml dry methanol. Small portions of FeCl 2 .4H 2 0 (0.95eq; 16.7g; 84.0mmoles) were added, yielding a clear red solution. After addition, the solution was stirred for 30 minutes at room temperature, after which the methanol was removed (rotary- evaporator) . The dry solid was ground and 150 ml of ethylacetate was added and the mixture was stirred until a fine red powder was obtained. This powder was washed twice with ethyl acetate, dried in the air and further dried under vacuum (40 oC) . El. Anal. Calc. for [Fe (MeN4py) Cl] Cl .2H 2 0: C 53.03; H 5.16; N 12.89; Cl 13.07; Fe 10.01%. Found C 52.29/ 52.03; H 5.05/5.03; N 12.55/12.61; Cl : 12.73/12.69; Fe : 10.06/10.01%. Complex 2: [ (N4Py) FeCl] Cl Complex 2 was synthesised according to the procedure as described for the analogous MeN4py complex using now N4py (N, N-bis (pyridin-2-yl-methyl) -1, 1-bis (pyridin-2-yl) -1- aminomethane) as ligand (see above) . The N4py ligand has been prepared as described in Wo-A-9534628. Complex 3 [ (N3pyMe) Fe (CH 3 CN) 2 ] (C10 4 ) 2 This compound has been synthesised as described elsewhere (WO0060044). (N3pyMe = 1, 1-bis (pyridin-2-yl) -N-methyl-N- (pyridin-2-ylmethyl) methylamine Complex 4: [Fe (LI) ] Cl] PF 6 (L1=N-Methyl-N,N' ,N' -tris (3-methylpyridin- 2ylmethyl) ethylenediamine) .This compound has been synthesised as described elsewhere (WO0027976) . Complex 5: [Fe (N-Methyl-N, N' , N' -tris (pyπdin- 2ylmethyl) ethylenediamme] Cl] PF e N-methyl-, N,N'N' -tris (pyπdin-2ylmethyl) ethane-diamme (trispicen-NMe) . This ligand was prepared according to a modified procedure described by Bernal et al (J. Chem. Soc, Dalton Trans, 22, 3667 (1995)). First N, N' -bis (pyπdιn-2ylmethyl) -ethanediamme (bispicen) was synthesised by the following procedure. Ethylenediam e (26 ml, 0.38 mol) was dissolved in 200 ml dry methanol. To this mixture 74 ml (0.76 mol) pyridmcarboxaldehyde was added. The mixture was refluxed for 2 h, after which the mixture was left to cool to RT and m small portions 40 g of NaBH 4 was added. The mixture was subsequently stirred for 16 h at RT . The methanol was evaporated and 500 ml of water was added. The aqueous mixture was extracted with three portions of dichloromethane (100 ml) and the dichloromethane solution was dried over sodium sulphate, filtered off and the solvent was removed. The dark oil containing N, N' -bis (pyπdm- 2ylmethyl) -ethanediamme (73.7 g; 81%) was analysed by NMR and used without further purification. 1 H-nmr (CDC1 3 ) : δ 2.20 (br, NH) ; 2.78 (s, 4H) ; 3.85 (s, 4H) ; 7.00-7.40 (m, 4H) ; 7.58 (m, 2H) ; 8.45 (m, 2H) . In the second step the ammal of bispicen with 2- pyπdmcarboxaldehyde was synthesised. 73,7 g of the unpuπfied bispicen material (see above) was under argon dissolved m 750 ml of dry diethyether. To this solution 32.8 of 2-pyπdmcarboxaldehyde was added, the reaction mixture was stirred and cooled in an ice/water bath. After 20 mm a white precipitate was formed that was filtered off (P4-glass filter) and dried with dry ether. The yield was 66.6 g (66%) and was used without further purification. x H-nmr (CDC1 3 ) : δ 2.75 (m, 2H) ; 3.13 (m, 2H) ; 3.65 (d, 2H) ; 4.93 (d, 2H) ; 4.23 (s, IH) ; 7.00-7.90 (m, 9H) ; 8.43 (m, 3H) . In the third step the desired ligand was obtained (N,N,N'~ tris (pyridin-2ylmethyl) ethane-diamine - trispicen-NH) . The aminal (45.0 g; 0.135 mol), obtained as described as above, was dissolved in 1.2 1 of dry methanol (distilled over Mg) , and to this mixture 8.61 g (0.137 mol) of NaBCNH 3 was added in small portions. Subsequently 21 ml of trifluoroacetic acid was added dropwise in the solution. The mixture was stirred for 16 h at RT and subsequently 1.05 L of 5N NaOH was added and the mixture was stirred for 6 h. Extraction with dichloromethane yielded after drying, filtration and removal of the solvent a yellow oil as product (42.7 g , 0.128 mol; 95%. 1 H-nmr (CDC1 3 ) : δ 2.15 (br, NH) ; 2.75 (s, 4H) ; 3.80 (s, 4H) ; 3.82(s, 2H) ; 7.0-7.8 (m, 3H) ; 7.45-7.70 (m, 6H) ; 8.40-8.60 (m, 3H) . 13 C-nmr (CDC1 3 ): δ53.9 (t); 54.7 (t); 60.4 (t); 121.7 (d) ; 121.9 (d) ; 122.1 (d) ; 123.0 (d) ; 136.3 (d); 136.4 (d) ; 148.9 (d) ; 149.1 (d) ; 159.3 (s) ; 159.6 (s) . The desired ligand was obtained by the following procedure: trispicen-NH (lOg, 30 mmol) was dissolved in 25 ml formic acid and 10 ml water. To this mixture 36 % formaldehyde solution was added (16 ml, 90 mmol) and the mixture was warmed up till 90 °C for 3 h. Formic acid was evaporated and the 2.5 N NaOH solution was added until the pH was higher than 9. Extraction by dichloromethane and drying over sodium sulfate, filtration of the solution and subsequently drying yielded a dark-coloured oil (8.85g). The oil was purified over a alumina column (elutant: ethyl acetate/ hexane/ tnethylamine 9:10:1). Yield 7,05g pale yellow oil (20,3mmoles; 68%). ^-n r (CDC1 3 ) : δ 2.18 (s, 3H) ; 2.65 (m, 2H) ; 2.75 (m, 2H) ; 3.60 (s; 2H) ; 3.83 (s; 4H) ; 7.10 (m, 3H) ; 7.3-7.6 (m, 6H) ; 8.5 (d, 3H) . The iron complex 5 has been synthesised as follows: TrispicenNMe (6,0g; 17,3mmoles) was dissolved in 15 ml methanol/water 1/1 v/v) and was heated till 50 °C. FeCl 2 .4H 2 0 3,43g; 17,0mmoles), dissolved m 20 ml water/methanol 1/1), was added. The dark solution was stirred for 20 mm at 50 °C. Subsequently 3.17 g (17 mmol) of KPF 6 dissolved in 10 ml water, was added and the solution was stirred for 15 h to yield a yellow precipitation. The solid was filtered off, wasged with methanol/water 1/1, v/v) and ethyl acetate. Drying yielded 8.25 g of a pale-yellow powder. Complex 6: [ (tpen) Fe] (C10 ) 2 This compound was prepared according to the procedure found in H. Toftlund et al., J. Am. Chem. Soc, 112, 6814 (1990). (tpen=tetrakιs (pyπdm-2-ylmethyl) ethylenediamme) . Complex 7: [Fe ( 1- [di (2-pyπdmyl) methyl] -4 , 7-dιmethyl-l, 4, 7- tπazacyclonane) (CH 3 CN) ] ( C10 4 ) 2 This compound was made as described elsewhere (WO006004). Experimental : Experiments were conducted to investigate bleaching performance of the bleach catalysts and one free ligand in a formulation on tomato stam, and dye fading properties on O.06.CS (Direct Green monitor) in the presence of the bleach catalysts or ligand. Formulation A: Na-LAS: 8.7% Nonionic 7EO, branched: 4.6 % Nonionic 3E0, branched: 2.4 % Soap: 1.1 % Zeolite A24 (anhydrous) 29.6 % Na-citrate 2 aq: 3.5 % SCMC - sodium carboxy ethylcellulose ( 68%) 0.5 % Moistures, salts, NDOM 4.8 % PVP: K-15 solution, ISP technologies, Inc . 0.6 % Stam: tomato-soya sauce oil stam Dye: O.06.CS (Direct Green monitor) A stock solution of 3 g/1 of formulation A in water (16 °FH) was prepared. The containing 10 μM of the metal catalyst or 20 μM of the ligand. Bottles tests were done (25 mL solution) containing 10 μM of the metal catalyst or 20 μM of the ligand, each bottle containing a O.06.CS cloth (Direct Green monitor - 4x4 cm) . In a seperate series of tests, a tomato stained cloth (4x4 cm) was added m the bottle, with no dyed cloths present. In compaπtive experiments no catalysts or ligand was added (blank) or the formulation A il - was used with 0.57 g TAED added, 0.03 g Dequest 2047 and 0.165 g percarbonate (PC) (current bleach product). The cloths were washed for 30 min at 40 °C. After the wash, the cloths were rinsed with water and subsequently dried, and the change in reflectance at 460 nm was measured immediately after drying on a Minolta CM-3700d spectrophotometer including a UV-Vis filter before and after treatment (t=0 in the table) . The cloths were subsequently stored for 24 h under ambient conditions and measured again (t=l in the table) . The difference in ΔR between both reflectance values gives a measure of the bleaching performance of the system on the stain, i.e. a higher ΔR value corresponds to an improved bleaching performance. On the other hand, a higher ΔR value for the dyed cloth indicates more dye fading which is undesired. The results for bleaching performance on tomato stains and dye fading are shown in the table below. S 2 - Table 4 The results in Table 4 indicate that: The compounds give significant bleaching of tomato stain in the absence of hydrogen peroxide. No dye fading effect on the bleach sensitive monitor 0.06CS was observed, even though the current bleach- containing product gives a significant dye fading.

Claims: CLAIMS : 1. A method of reducing dye fading of fabrics in laundry bleaching compositions, comprising contacting stained fabric, in a wash liquor, with a bleaching composition that comprises a bleach catalyst, wherein the bleach catalyst comprises a ligand which forms a complex with a transition metal, the complex catalysing bleaching of stains by atmospheric oxygen, and the composition is substantially devoid of peroxygen bleach or a peroxy-based or -generating bleach system. 2. A method according to claim 1, wherein the wash liquor is an aqueous medium. 3. A method according to claim 1 or claim 2, wherein the amount of catalyst in the composition in the wash liquor is from 0.5 μM to 100 μM, preferably from 1 μM to 10 μM 4. A method according to any preceding claim, wherein the catalyst comprises a pentadentate ligand of the general formula (IVE) : IVE) wherein each R 1 , R 2 independently represents -R-R 5 , R 3 represents hydrogen, optionally substituted alkyl, aryl or arylalkyl, or -R 4 -R 5 , each R 4 independently represents a single bond or optionally substituted alkylene, alkenylene, oxyalkylene, a inoalkylene, alkylene ether, carboxylic ester or carboxylic amide, and each R 5 independently represents an optionally N- substituted aminoalkyl group or an optionally substituted heteroaryl group selected from pyridinyl, pyrazinyl, pyrazolyl, pyrrolyl, imidazolyl, benzimidazolyl, pyrimidinyl, triazolyl and thiazolyl. 5. A method according to any preceding claim, wherein the ligand is N, N-bis (pyridin-2-yl-methyl) -1, 1-bis (pyridin-2- yl) -1-aminoethane. 6. A method according to any preceding claim, wherein the ligand forms a complex of the general formula: [M a L k X n ] Y π in which : M represents a metal selected from Mn (II) - (III) - (IV) - (V), Cu(I)-(II)-(III), Fe ( II ) - ( III ) - ( IV) - (V) , Co(I)-(II)- (III), Ti(II)-(III)-(IV) , V(II)-(III)-(IV)-(V), Mo(II)- (III) - (IV) -(V)- (VI) and ( IV) - (V) - (VI ) , preferably from Fe (II)-(III)-(IV)-(V); L represents the ligand, or its protonated or deprotonated analogue; X represents a coordinating species selected from any mono, bi or tπ charged anions and any neutral molecules able to coordinate the metal m a mono, bi or tridentate manner; Y represents any non-coordinated counter ion; a represents an integer from 1 to 10; k represents an integer from 1 to 10; n represents zero or an integer from 1 to 10; m represents zero or an integer from 1 to 20. 7. A method according to any preceding claim, wherem the composition provides a pH value in the range from pH 6 to 11, preferably m the range from pH 8 to 10, in aqueous medium. 8. A method according to any preceding claim, wherem the composition is substantially devoid of a transition metal sequestrant . 9. A method according to any preceding claim, where the composition further comprises a surfactant. 10. A method according to claim 9, wherem the composition further comprises a builder. 11. A method according to any of claims 1 to 10, wherem the catalyst comprises a preformed complex of the ligand and a transition metal. 16 - 12. A method according to any of claims 1 to 10, wherein the composition comprises free ligand that complexes with a transition metal present in the water. 13. A method according to any of claims 1 to 10, wherein the composition comprises a free ligand that complexes with a transition metal present in the substrate. 14. A method according to any of claims 1 to 10, wherein the composition comprises free ligand or a transition metal- substitutable metal-ligand complex, and a source of transition metal. 15. Use of a bleach catalyst that comprises a ligand which forms a complex with a transition metal, the complex catalysing bleaching of stains by atmospheric oxygen in a bleaching composition in a wash liquor that is substantially devoid of peroxygen bleach or a peroxy-based or -generating bleach system, to reduce dye fading of fabrics contacted with the bleaching composition.

Inventors: CHAPPLE ANDREW PAUL, JONES JANE ANN, LLOYD JOHN, THIJSSEN ROB, VEERMAN SIMON MARINUS, CHAPPLE, ANDREW, PAUL, JONES, JANE, ANN, LLOYD, JOHN, THIJSSEN, ROB, VEERMAN, SIMON, MARINUS
Applicants: LEVER HINDUSTAN LTD, UNILEVER NV, UNILEVER PLC, HINDUSTAN LEVER LIMITED, UNILEVER N.V.
Application year: 2001
Main classification: D06L3
IPC codes: C11D3