bluuebunny/crossref_metadata_2025_split huggingface dataset:
Manganese Oxydiacetate Complexes: Synthesis, Structure and Magnetic Properties
Authors: Grirrane Abdessamad , Pastor Antonio , Álvarez Eleuterio , Mealli Carlo , Ienco Andrea , Rosa Patrick , Montilla Francisco , Galindo Agustín 
Published: February 2004

AbstractThe aerobic aqueous solution syntheses and structures of monomeric and polymeric MnII complexes containing the oxydiacetate ligand [O(CH2COO)22− = oda] are reported. The magnetic properties of the polymeric products have also been investigated. The initially obtained species [{Mn(oda)(H2O)}·H2O]n (1) has been reacted with bidentate or tridentate N‐donor ligands such as o‐phenanthroline (phen), 2,2′‐bipyridine (bipy) and 2,2′:6,2′′‐terpyridine (terpy) to give the complexes [{Mn(oda)(phen)}·4H2O]n (2), [Mn(oda)(bipy)(H2O)]·2H2O (3) and [Mn(oda)(terpy)]·2H2O (4), respectively. Species 1−4 are the first Mn‐oda structures determined by X‐ray methods. In all cases, the oda acts as a tridentate ligand toward one metal and adopts the typical planar arrangement. However, while the 3 and 4 are monomers, 2 and 1 are polymers as oda exploits both atoms of its carboxylate groups to coordinate other metals; 1 consists of a three‐dimensional diamond‐type network, while 2 is one‐dimensional, consisting of an extended chain of {Mn(oda)(phen)} subunits. For both compounds, magnetic susceptibility measurements down to 2 K showed only weak antiferromagnetic interactions between high‐spin MnII ions. Despite the expectedly similar coordinating capabilities of N‐donor ligands, the bipy complex 3 is a monomer with the six‐coordination completed by one water ligand. The tridentate nature of simultaneously present oda and terpy ligands excludes the coordination of water in complex 4, the geometry of which is distorted from the octahedron, most likely due to a peculiar packing effect. Finally, the known five‐coordinate complex [MnCl2(terpy)] (5), a side product of our synthetic experiments, has also been structurally characterized. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
Synthesis, Characterization and Near‐Infrared Photoluminescence of Monoporphyrinate Lanthanide Complexes Containing an Anionic Tripodal Ligand
Authors: He Hongshan , Guo Jianping , Zhao Zhixin , Wong Wai‐Kwok , Wong Wai‐Yeung , Lo Wing‐Kit , Li King‐Fai , Luo Li , Cheah Kok‐Wai 
Published: February 2004

AbstractTwelve neutral stable complexes of ytterbium(III) and erbium(III) coordinated by anionic hydridotris(pyrazol‐1‐yl)borate andmeso‐tetraphenylporphyrinate, and its derivatives with different substituents in theparaposition of the phenyl groups, were prepared and characterized. Crystal structure analyses revealed that seven nitrogen atoms, four from the porphyrinate dianion and three from the anionic tripodal ligand, are symmetrically coordinated to the lanthanide ions. Photophysical investigations of the complexes showed an enhancement of near‐infrared photoluminescence as compared to aqua‐coordinated monoporphyrinate lanthanide complexes. The solvent effect and substituent effects on the photoluminescent properties of the complexes were also investigated (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004).
Synthesis, Characterization and Properties of Transition Metal Pd/Pt [60]Fullerene Complexes Containing Phosphane Ligands − Crystal Structure of [Pd(η2‐C60){Ph2PCH2(CH2OCH2)2CH2PPh2}]
Authors: Song Li‐Cheng , Yu Guang‐Ao , Wang Hu‐Ting , Su Fu‐Hai , Hu Qing‐Mei , Song Ying‐Lin , Gao Ya‐Chen 
Published: February 2004

AbstractA solution of C60 in toluene reacts with Pd(dba)2 or Pd2(dba)3 (dba = dibenzylideneacetone) and monophosphanes in a 1:1:2 molar ratio to give the corresponding Pd monophosphane fullerene derivatives [Pd(η2‐C60)L2] [L = P(2‐Fu)3 (Fu = furyl) 1; L = P(2‐Fu)Ph2 2; L = PPh2H 3; L = P(Fc)Ph2 (Fc = ferrocenyl) 4; L = P(Fc)2Ph 5], whereas reaction with M(dba)2 (M = Pd, Pt) and subsequent treatment with diphosphanes in 1:1:1 molar ratio afforded the corresponding Pd/Pt diphosphane fullerene complexes [Pd(η2‐C60){Ph2PCH2(CH2OCH2)nCH2PPh2}] (n = 1 6; n = 2 7; n = 3 8) and [Pt(η2‐C60){Ph2PCH2(CH2OCH2)nCH2PPh2}] (n = 1 9; n = 2 10; n =3 11). All the new fullerene complexes 1−11 were characterized by elemental analysis, IR, 1H NMR and 31P NMR spectroscopy, as well as by X‐ray diffraction analysis (for 7). The optical limiting properties of 3−5 were determined and the possible pathways for the “one pot” reactions leading to 1−11 are briefly discussed. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
Synthesis, Structural, Magnetic and Electrochemical Studies of Antiferromagnetically Coupled Symmetric Oxamidate‐Bridged Binuclear Copper(II) Complexes
Authors: Saravanakumar Duraisamy , Sengottuvelan Nallathambi , Narayanan Vengidusamy , Kandaswamy Muthusamy , Chinnakali Kandaswamy , Senthilkumar Gopal , Fun Hoong Kun 
Published: February 2004

AbstractThe new binuclear copper(II) complexes Cu2L1−3 and [Cu2L4,5](ClO4)2 were synthesized by reaction of the monomeric cis‐N,N′‐bis(3‐aminopropyl)oxamidatocopper(II) complex [Cu(oxpn)] with acetylacetone, benzoylacetone, salicylaldehyde, 2‐pyridinecarboxaldehyde and diacetyl monoxime in the presence of copper(II) acetate or perchlorate owing to the trans isomerisation of the cis‐oxamidato complex. The crystal structure of Cu2L1 consists of centrosymmetric binuclear copper(II) ions which are bridged by an oxamidato group in the trans conformation with a copper−copper distance of 5.121 Å. Each copper(II) ion occupies an inner site of the N2O2 donor with a distorted square‐planar environment. Electrochemical studies showed that two quasireversible one‐electron reduction waves are obtained in the cathodic region (E1pc = −0.48 to −1.02 V, E2pc = −1.08 to −1.34 V). The conproportionation constants Kcon for the mixed‐valence CuICuII complexes have been determined electrochemically. Room‐temperature magnetic‐moment studies of binuclear copper(II) complexes reveal the presence of a strong antiferromagnetic interaction (μeff = 1.14−1.24 μB) which is also observed from the broad spectra with g = 2.1. A variable‐temperature magnetic‐susceptibility study of the complexes 1 and 4 gives J values of −510 cm−1 and −497 cm−1 respectively. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
Dimeric Metallo‐Organic Supramolecular Quinoxaline Stacking Synthons
Authors: Heirtzler Fenton , Dias Sandra , Neuburger Markus 
Published: February 2004

AbstractCondensation of ortho‐phenylene diamines with an unsymmetrical 2,6′‐bipyridyl‐2′′‐pyridyl α‐diketone (2) affords helical ligands 3a and 3b that self‐assemble in the presence of copper(I) to produce the helical, dimeric metallo‐organic complexes [3a2Cu2][PF6]2 and [3b2Cu2][PF6]2. These complexes have a flat, double‐decker‐like structure that results from atopomeric twisting in the ligand scaffolding, as confirmed by X‐ray crystal structural analysis on [3a2Cu2][PF6]2. This study also indicates a close parallel between the distances involved in inter‐ and intramolecular stacking phenomena. Detailed NMR spectroscopic analysis of both complexes indicates that their dications possess very closely related solution‐state structures. Achieving this self‐assembly program is an important step towards realizing dimerically self‐assembled metallo‐organic materials that have a discotic alignment. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
Some Properties and Molecular Orbitals of Planar Heterodinuclear Phthalocyanines
Authors: Kobayashi Nagao , Ogata Hiroshi 
Published: February 2004

AbstractThe electronic absorption and magnetic circular dichroism (MCD) spectra, and differential pulse (DP) voltammograms of planar heterodinuclear phthalocyanine (Pc) dimers consisting of Pc and pyrazinoporphyrazine (PyZ), [Mt2PcPyZ (Mt = H2 and Zn)] and of Pc and naphthalocyanine (Nc), [Mt2PcNc (Mt = H2 and Co)] have been recorded. These dimers commonly show broad absorption bands between ca. 500 and 1000 nm, while the DP voltammograms suggest that the dimers are unstable towards oxidation, and that the two relatively independent chromophore units interact with one another. Molecular orbital (MO) calculations using the ZINDO/S Hamiltonian were performed in order to enhance the interpretation of the experimental results. Dimer orbitals were expressed by coupling the orbitals of the same symmetry, of the constituting mononucleates. It was suggested that for the HOMO of the dimers, the contribution of the more electron‐rich moiety is large, while conversely for the LUMO, the contribution of the more electron‐deficient moiety is large. The calculations suggested that there are three prominent transitions in the Q band region of the heterodimers. The intensity and position of these bands were suggested to be affected by the constituting mononucleates. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
Tandem Palladium‐Catalyzed Cyclocarbonylation of Isolimonene: A Mechanistic Investigation and Theoretical Calculations on the Fully Diastereoselective Step
Authors: Lenoble Géraldine , Lacaze‐Dufaure Corinne , Urrutigoïty Martine , Mijoule Claude , Kalck Philippe 
Published: February 2004

AbstractCyclocarbonylation of isolimonene catalyzed by complexes of the type [HPd(SnCl3)L2] provides two cyclopentanone isomers (2a and 2b) containing two new stereogenic centers with a good diastereomeric excess (up to 69 % with L2 = dppf). These results show that chiral phosphane ligands are not necessary to ensure asymmetric induction. The diastereomeric excess is due, in fact, to the substrate itself, assisted by the steric hindrance of the diphosphanes. A full characterization of the two isomers by 1H, 13C and DPFGSE NOE NMR spectroscopy gives all the signal assignations and all the positions of the substituents of interest on the chiral carbon atoms. In order to have a better understanding of the catalytic process, we also present a density functional study of the crucial intermediate species 4 involved in the proposed catalytic cycle. Our calculations show that there is no coordination of the C=C bond in an exo mode. Conversely, we have found a pentacoordinate species with a trigonal bipyramidal geometry in which the C=C bond is coordinated in an endo mode. Selected bond lengths and bond orders are reported. The calculated net charge distribution supports the cyclization process, which proceeds through a C−C(O) and a C−Pd coupling. A β‐hydride elimination reaction of 4 provides the two 2a and 2b isomers. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
Synthetic and Structural Studies of PdII and PtII Complexes with Quincorine and Quincoridine Derivatives
Authors: Fild Manfred , Thöne Carsten , Tötös Stefania 
Published: February 2004

AbstractA series of PdII‐quincorine and ‐quincoridine complexes in which the ligands are coordinated through N,O‐donor atoms have been synthesised, and their structural features determined by X‐ray crystallography. Additionally, new chiral tetradentate N,P‐ligands containing two quinuclidine cores bridged through a cis‐enediyne fragment have been obtained. The different coordinating properties of the new ligands, which contain two soft phosphorus and two hard nitrogen donors, to PdII and PtII are emphasised. Several typical complexes were structurally characterised by X‐ray crystallography. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
Hydration of Propargylic Alcohols by Ruthenium Catalysts, with Dominant Anti‐Markovnikov Regioselectivity, Formation of α,β‐Unsaturated Products and Catalytic Decarbonylation to 1‐Alkenes
Authors: d'Alessandro Nicola , Di Deo Milena , Bonetti Monica , Tonucci Lucia , Morvillo Antonino , Bressan Mario 
Published: February 2004

AbstractRuthenium catalysts — water‐soluble ruthenium sulfophthalocyanine and heterogeneous ruthenium hydroxyapatite complexes — proved to be effective for the hydration of propargylic alcohols in entirely aqueous media. 1‐Phenyl‐2‐propyn‐1‐ol underwent an unprecedented catalytic hydration‐decarbonylation‐dehydration reaction, giving rise to styrene and carbon monoxide; 2‐propyn‐1‐ol and 3‐butyn‐2‐ol gave predominantly the products of anti‐Markovnikov addition, together with products of hydration‐dehydration (α,β‐rearrangement) and, to a minor extent, the decarbonylation products, ethene or propene, respectively. Hydrations were also conducted in D2O, giving indications of the mechanism of the reactions and apparently ruling out the allenylidene route for the α,β‐rearrangement. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
Anomalous Difference in Magnetic Behavior between Highly Saddled Iron(III) Porphyrin Complexes in the Solid State
Authors: Ohgo Yoshiki , Ikeue Takahisa , Takahashi Masashi , Takeda Masuo , Nakamura Mikio 
Published: February 2004

AbstractThe spin states of microcrystalline samples of [Fe(OMTPP)L2]+ (L = DMAP or Py) have been examined and interpreted using Mössbauer spectroscopy, SQUID magnetometry and X‐ray crystallography. The Mössbauer spectra of [Fe(OMTPP)(DMAP)2]+ and [Fe(OMTPP)Py2]+ showed that both of these complexes maintain the low‐spin (S = 1/2) state over the 77−300 K temperature range. The spin states of these complexes were further confirmed by SQUID magnetometry. Thus, the magnetic behavior of [Fe(OMTPP)Py2]+ is quite different from that of the structurally related species [Fe(OETPP)Py2]+. The latter complex exhibits a novel spin crossover between the S = 3/2 and S = 1/2 states as revealed by the spectroscopic and magnetic measurements. In order to understand the reasons for the absence of the spin crossover process in [Fe(OMTPP)Py2]+, we have compared the crystal and molecular structures of [Fe(OMTPP)Py2]+ with those of the recently reported species [Fe(OETPP)Py2]+. In the case of [Fe(OMTPP)Py2]+, the Fe−Naxial bond lengths hardly change with temperature and are 2.058(6) and 2.024(4) Å at 298 and 80 K, respectively. These results are in sharp contrast to those of the spin crossover complex [Fe(OETPP)Py2]+, in which the Fe−Naxial bonds contract from 2.201(3) Å at 298 K to 1.993(3) Å at 80 K. We have ascribed the difference in magnetic behavior between [Fe(OMTPP)Py2]+ and [Fe(OETPP)Py2]+ to the difference in molecular packing; the former adopts a densely packed cubic crystal system while the latter shows a less condensed monoclinic system. A cavity calculation has further confirmed the above mentioned assumption. While the cavity sizes around the pyridine ligands in [Fe(OETPP)Py2]+ are 32.08 and 28.88 Å3 at 298 K, that in [Fe(OMTPP)Py2]+ is only 19.81 Å3. Furthermore, the cavities contract by 17.7% in [Fe(OETPP)Py2]+ when the temperature is lowered from 298 to 80 K whereas the contraction is only 5.3% in the case of [Fe(OMTPP)Py2]+. On the basis of these results, we have concluded that the loosely packed crystal system and the wide cavities around the axial ligands are the important requirements for the occurrence of the spin crossover process in the solid state. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
Preparation of 17 Sulfur‐Rich Chain‐Like Thiaalkanes R−Sx−R′−Sy−R and R−Sx−R′−Sy−R′−Sz−R (x, y, z > 2) from Titanocene Thiolate Complexes
Authors: Münchow Vera , Steudel Ralf 
Published: February 2004

AbstractTwo novel Cp2Ti(Cl)S3R′S3Tr complexes have been prepared by reaction of the six‐membered metallacycles Cp2TiS4R′ (Cp = η5‐C5H5, R′ = CMe2, 1,1‐C6H10) with the sulfenyl chloride TrSCl (Tr = CPh3) at 20 °C. These complexes were treated with: (a) sulfenyl chlorides (RSCl or RSSCl) to obtain 11 new thiaalkanes of the type R−Sx−R′−Sy−R (R = Tr, 4‐ClC6H4, 2‐C10H7; x = 3, y > 2), or (b) with SO2Cl2, SCl2 or S2Cl2 to prepare six sulfur‐rich species of the type Tr−Sx−R′−Sy−R′−Sz−Tr (x, z = 3, y > 3), as well as Cp2TiCl2. The thiaalkanes decompose upon heating to give mixtures of various linear and cyclic polysulfanes R2Sn and R′Sm. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
Inorganic−Organic Hybrid Compounds: Synthesis and Structures of New Metal Organic Polymers Synthesized in the Presence of Mixed Dicarboxylates
Authors: Thirumurugan A. , Natarajan Srinivasan 
Published: February 2004

AbstractA hydrothermal reaction of a mixture of 1,2‐dicyanobenzene (1,2‐DCB), 1,4‐benzene‐dicarboxylic acid (1,4‐BDC) along with the corresponding lanthanide salts at a pH of ≈︁ 5, gives rise to a new series of carboxylate coordination polymers, [M2(H2O)4{(1,2BDC)2(1,4BDC)}], (M = La, Pr, Gd, Dy, and Y), which are three‐dimensional in structure. The 1,2‐DCB oxidized to the corresponding dicarboxylic acid, phthalic acid (1,2‐BDC), during the reaction. The structures are of two types with the larger La and Pr lanthanides forming type‐1 and the smaller ones, Gd, Dy, and Y, forming type‐2. While La and Pr have an idealizedD3htriply capped trigonal prism coordination environment, Gd, Dy, and Y have a distorted dodecahedral arrangement with respect to the oxygen atoms. The three‐dimensional structure consists of a column of M atoms connected through the 1,2‐BDC, and is cross‐linked through 1,4‐BDC giving rise to rhombic one‐dimensional channels. The water molecules, bound to the M atoms, project into the channels. The compounds also illustrate the lanthanide contraction principle. The compounds have been characterized using powder X‐ray diffraction, TGA, IR, and photoluminescence measurements. Our continuing investigations clearly reveal that related compounds can be formed with all the rare earth metal ions. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
Non‐Heme Iron Complexes for Stereoselective Oxidation: Tuning of the Selectivity in Dihydroxylation Using Different Solvents
Authors: Klopstra Marten , Roelfes Gerard , Hage Ronald , Kellogg Richard M. , Feringa Ben L. 
Published: February 2004

AbstractA new class of functional models for non‐heme iron‐based dioxygenases, including [(N3Py‐Me)Fe(CH3CN)2](ClO4)2 and [(N3Py‐Bn)Fe(CH3CN)2](ClO4)2 {N3Py‐Me = [di(2‐pyridyl)methyl]methyl(2‐pyridyl)methylamine; N3Py‐Bn = [di(2‐pyridyl)methyl]benzyl(2‐pyridyl)methylamine}, is presented here. NMR, UV and X‐ray analyses revealed that six‐coordinate low‐spin FeII complexes with the pyridine N‐atoms and the tertiary amine functionality of the ligand bound to Fe are formed. The two remaining coordination sites located cis to each other are occupied by labile CH3CN groups that are easily exchanged by other ligands. We demonstrate that the reactivity and stereoselectivity of the complexes investigated depend on the choice of the solvent. The complexes have been examined as catalysts for the oxidation of both alkanes and olefins in CH3CN. In this solvent alkanes are oxidized to alcohols and ketones and olefins to the corresponding cis‐epoxides and cis‐diols. In acetone as solvent a different reactivity pattern was found, with, as the most striking example, the trans‐dihydroxylation of cis‐olefins. 18O‐labeling studies in CH3CN establish incorporation of 18O from H218O2 and H218O in both the epoxide and the diol implicating an HO‐FeV=18O active intermediate originating from an H218O‐FeIIIOOH species. These results are in full agreement with mechanistic schemes derived for other dioxygenase model systems. Based on labeling studies in acetone an additional oxidation mechanism is proposed for this solvent, in which the solvent acetone is involved. This is the first example of a catalyst that can give cis‐ or trans‐dihydroxylation products, just by changing the solvent. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
Stannaborate Chemistry: Nucleophilic Substitution at the Cluster Sphere
Authors: Ronig Benno , Bick Torsten , Pantenburg Ingo , Wesemann Lars 
Published: February 2004

AbstractNucleophilic substitution at (γ‐chloropropyl)stanna‐closododecaborate [Cl(CH2)3SnB11H11]− with RLi [R = Ph, Me2NC6H4, ferrocenyl (Fc)] and RMgBr (R = vinyl, benzyl) affords the substitution products containing the anion [RSnB11H11]−. The reaction products have been characterized by elemental analysis, NMR spectroscopy and in the cases where R = Ph, Me2NC6H4, Fc and vinyl by X‐ray structure analysis. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
Cover Picture: Some Properties and Molecular Orbitals of Planar Heterodinuclear Phthalocyanines (Eur. J. Inorg. Chem. 4/2004)
Authors: Kobayashi Nagao , Ogata Hiroshi 
Published: February 2004

AbstractThe cover picture shows planar heterodinuclear phthalocyanine (Pc) dimers consisting of Pc and pyrazinoporphyrazine and of Pc and naphthalocyanine. In the picture, red spheres indicate nitrogen atoms. These dimers commonly show broad absorption bands between ca. 500 and 1000 nm, while the differential pulse voltammetry and molecular orbital calculations suggest that the dimers are unstable to oxidation, and that the two relatively independent chromophore units interact. Details are discussed in the article by N. Kobayashi and H. Ogata on p. 906 ff.
Determination of the fatty acid profile by 1H‐NMR spectroscopy
Authors: Knothe Gerhard , Kenar James A. 
Published: February 2004

AbstractThe common unsaturated fatty acids present in many vegetable oils (oleic, linoleic and linolenic acids) can be quantitated by 1H‐nuclear magnetic resonance spectroscopy (1H‐NMR). A key feature is that the signals of the terminal methyl group of linolenic acid are shifted downfield from the corresponding signals in the other fatty acids, permitting their separate integration and quantitation of linolenic acid. Then, using the integration values of the signals of the allylic and bis‐allylic protons, oleic and linoleic acids can be quantitated. The procedure was verified for mixtures of triacylglycerols (vegetable oils) and methyl esters of oleic, linoleic and linolenic acids as well as palmitic and stearic acids. Generally, the NMR (400 MHz) results were in good agreement with gas chromatographic (GC) analyses. As the present 1H‐NMR‐based procedure can be applied to neat vegetable oils, the preparation of derivatives for GC would be unnecessary. The present method is extended to quantitating saturated (palmitic and stearic) acids, although in this case the results deviate more strongly from actual values and GC analyses. Alternatives to the iodine value (allylic position equivalents and bis‐allylic position equivalents) can be derived directly from the integration values of the allylic and bis‐allylic protons.
Separation of capsular polysaccharide K4 and defructosylated K4 by high‐performance capillary electrophoresis
Authors: Volpi Nicola 
Published: February 2004

AbstractA rapid, highly sensitive and reproducible high‐performance capillary electrophoresis (HPCE) method (electrokinetic chromatography with sodium dodecyl sulfate) is described for the determination of the polysaccharide from the uropathogenic Escherichia coli K4 bacteria (05:K4:H4) and its defructosylated product. The two polyanions, K4 and defructosylated K4, are separated and readily determined within 30 min on an uncoated fused‐silica capillary using normal polarity at 20 kV and detection at 200 nm. A linear relationship was found for the two polysaccharides over a wide range of concentrations, from approximately 30 ng (0.5 μg/μL) to 210 ng (3.5 μg/μL). The described method was used to evaluate the defructosylation process of K4 under drastic acid conditions.