bluuebunny/crossref_metadata_2025_split huggingface dataset:
Kinetics of Oxygen Exchange between Arsenate Ions and Water. II. Catalysis by Arsenious Acid
Authors: Okumura Akiko , Yamamoto Noriko , Okazaki Nobukazu 
Published: July 2006

Abstract
Oxygen exchange between arsenate ions and water is catalyzed by arsenious acid. The catalytic effect has been studied at 14.5 °C and 30.0 °C over the pH region of 7.5–10.2. The increase in the exchange rate due to the addition of arsenious acid, Rc may be expressed as: Rc≈k[H+][As(III)][As(V)]. The results are interpreted in terms of the rapid reversible condensation of the As(III) with the As(V) species to form the arsenitoarsenate ions.
Circular Dichroism and Optical Rotatory Dispersion Spectra of Poly[γ-(1-naphthylmethyl)-l-gIutamate] and Its Charge-transfer Complex
Authors: Hatano Masahiro , Enomoto Takamichi , Ito Ichi , Yoneyama Michio 
Published: July 2006

Abstract
Poly-γ-(1-naphthylmethyl)-l-glutamate was synthesized and its structure analyzed by the measurements of circular dichroism and absorption spectra. When the circular dichroism band at 219 nm in the circular dichroism spectrum of the polymer can be assigned to the band due to n–π* transition in the peptide main chain of the polymer, the calculated content of the right hand helix in the polymer is about 54% in ethylene chlorohydrin solution. It was also found that the polypeptide can form a charge-transfer complex with an organic electron acceptor in ethylene chlorohydrin solution. In the charge-transfer complex, a circular dichroism band could be observed at the wavelength corresponding to that of the charge-transfer band in the absorption spectrum of the complex. From the results, it was confirmed that the charge-transfer complex contains α-helix structure of this polypeptide. The temperature dependence of the charge-transfer complex formation was discussed in terms of the formation constant and thermodynamic parameters. The polypeptides having various portions of the 1-naphthylmethyl-d-glutamate residue were synthesized from poly-γ-methyl-d-glutamate by a polymer reaction using p-toluenesulfonic acid. The values of b0 for the polypeptides derived from poly-γ-methyl-d-glutamate were estimated by means of Moffitt-Yang’s equation, and the correlation between the b0 values and the contents of 1-naphthylmethyl residue in the polypeptides was discussed.
Determination of Electrochemical Kinetic Parameters of Porphyrins and Metalloporphyrins in N,N′-Dimethylformamide by Radio Frequency Polarographic Method
Authors: Kakutani Tadaaki , Senda Mitsugi 
Published: July 2006

Abstract
Electrochemical kinetic parameters were determined for the first two reduction steps of some porphyrins and divalent metalloporphyrins in DMF containing 0.5 M TEAP at 25 °C by use of radio frequency polarographic method. The results were discussed in view of their molecular structures and the diffuse double layer effect on the kinetic parameters.
A Study on Spontaneous Resolution of Cobalt(III) Complex Salts
Authors: Yamanari Kazuaki , Hidaka Jinsai , Shimura Yoichi 
Published: July 2006

Abstract
Solubility of the racemic and optically active isomers of [Co(ox)en2]X, [CoCO3en2]X, cis-[Co(NO2)2en2]X and M[Co(edta)] in water was determined at 5–60 °C (X=Cl, Br, and I; M=NH4 and K). The correlation between solubility of the spontaneously resolved racemic complex and of the corresponding optically active isomer is discussed. Spontaneous resolutions were observed for [Co(ox)en2]X (X=Cl, Cl·H2O, and Br·H2O), cis-[Co(NO2)2-en2]X (X=Cl and Br) and M[Co(edta)]·2H2O (M=NH4 and K).
The Chemical Behavior of Low Valence Sulfur Compounds. VIII. The Oxidation of Sodium Thiosulfate with Ozone
Authors: Takizawa Masahiro , Okuwaki Akitsugu , Okabe Taijiro 
Published: July 2006

Abstract
The oxidation of sodium thiosulfate with ozone in an aqueous solution was investigated as a part of a series of studies on the chemical behavior of such low-valence sulfur compounds as thiosulfate and sulfite. The ozone oxidation was carried out by blowing a mixed gas of ozone and oxygen continuously into a 0.3–0.6 mol/l solution of sodium thiosulfate at 10–80°C. In a neutral solution, thiosulfate is converted to sulfate, sulfite, tri- and tetrathionates, hydrogen sulfide and sulfur dioxide, and finally to sulfate, tri- and tetrathionates. The yield of the sulfate is only 40% of the total sulfur. In an alkaline solution, however, thiosulfate is oxidized to sulfite as an intermediate, and finally to sulfate.
The oxidation of sodium sulfite, and potassium salts of tri- and tetrathionate with ozone was also studied in order to elucidate its mechanism.
Studies on Reactions of the N-Phosphonium Salts of Pyridines. III. A New Method for the Activation of Amines via the N-Phosphonium Salts by Means of Oxidation of Phosphorous Acid and Its Esters in the Presence of Tertiary Amines
Authors: Yamazaki Noboru , Higashi Fukuji 
Published: July 2006

Abstract
Amines were treated with the N-phosphonium salts of pyridine prepared by the oxidation of the phosphorous acid and its esters with mercuric chloride in pyridine; they yielded the corresponding amides in good yields upon acidolysis with carboxylic acids, together with metallic mercury in a nearly quantitative yield. The reaction was studied using phosphorous acid and its several esters, and was presumed to proceed via the activation of amines by the N-phosphonium salts of pyridine which were characterized by IR spectroscopy. This process for the activation of amino groups was successfully extended to peptide synthesis in pyridine at low temperature using diphenyl phosphite.
Mechanism of Transylidation of Stable Sulfonium Ylids with Alkyl Sulfides in the Presence of Catalytic Disulfides
Authors: Matsuyama Haruo , Minato Hiroshi , Kobayashi Michio 
Published: July 2006

Abstract
In the presence of bis(trifluoromethyl) disulfide, methylphenylsulfonium bis(methoxycarbonyl)methylid is readily attacked by a nucleophile (an alkyl sulfide or a pyridine) and the corresponding new ylid is produced. In the NMR spectrum of a mixture of an ylid, an alkyl sulfide, and a catalytic disulfide, a remarkable broadening in the signals of the α-hydrogen of the sulfide was observed. A mechanism is suggested, which involves a complex from the two reactants and the catalyst.
α,β-Unsaturated Carboxylic Acid Derivatives. IV. General Synthesis of Unsaturated Unsymmetric 3,6-Disubstituted-2,5-piperazinediones
Authors: Shin Chung-gi , Sato Ken-ichi , Ohtsuka Akira , Mikami Kazutoshi , Yoshimura Juji 
Published: July 2006

Abstract
A general synthetic route to unsymmetric 3,6-dialkylidene and 3-alkylidene-6-arylidene-2,5-piperazinediones is described. The condensation reaction of ethyl 2-oxocarboxylates with chloroacetamide in the presence of several acidic catalysts afforded N-chloroacetyldehydroamino acid esters. These compounds were cyclized in saturated ethanolic ammonia to give 3-monoalkylidene and benzylidene-2,5-piperazinediones (2). Compound 2 and 1-monoacetyl- or 1,4-diacetyl-3-alkylidene and benzylidene-2,5-piperazinediones, derived from a reaction of 2 with acetic anhydride, were condensed with alkyl and arylaldehyde in the presence of bases to afford 5.
The Molecular Structure of Antimony Trichloride as Determined by Gas-electron Diffraction
Authors: Konaka Shigehiro , Kimura Masao 
Published: July 2006

Abstract
The molecular structure and mean amplitudes of SbCl3 have been determined, by the sector-microphotometer method of gas-phase electron diffraction, to be as follows: rg(Sb–Cl)=2.333±0.003 Å, rg(Cl–Cl)=3.50±0.02 Å, θα=97.2°±0.9°, l(Sb–C1)=0.063±0.004 Å, and l(Cl–Cl)=0.147±0.014 Å. The zero-point average structure derived from the diffraction results by the use of the estimated potential constants is consistent with the rotational constants, Bz, derived from the Bo of microwave measurements. The joint use of the ED and MW data has given a value of 2.326±0.001 Å for rz(Sb–Cl).
Electron Diffraction Study of Dimethylmercury
Authors: Kashiwabara Kuniaki , Konaka Shigehiro , Iijima Takao , Kimura Masao 
Published: July 2006

Abstract
Electron scattering by dimethylmercury has been studied for 42 keV electrons. The theoretical scattering factors currently used have shown satisfactory conformity to the observed scattering intensity, with the following distance parameters: rg(Hg–C)=2.083±0.005 Å, rg(Hg…H)=2.71±0.02 Å, and rg(C–H)=1.106 Å (assumed). A comparison of the background functions has revealed that the scattering factors based on the relativistic Hartree-Fock-Slater potential are better than those based on the Thomas-Fermi-Dirac and Thomas-Fermi potentials. The zero-point average distance determined from the spectroscopic data has shown significant inconsistency with the diffraction result. The diffraction value is shorter than the spectroscopic one by 0.015 Å.
Electron Diffraction Investigation of Gaseous Mercury(II) Chloride
Authors: Kashiwabara Kuniaki , Konaka Shigehiro , Kimura Masao 
Published: July 2006

Abstract
The molecular structure of mercury (II) chloride has been determined by the sector-microphotometer method of gas-phase electron diffraction at accelerating voltages of 29 and 42 kV. The parameter values obtained are: rg(Hg–Cl), 2.252±0.005 Å; l(Hg–Cl), 0.052±0.005 Å; rg(Cl–Cl), 4.48±0.04 Å; and l(Cl–Cl), 0.09±0.04 Å. A linear structure has been confirmed within an error of 16°. The experimental mean amplitudes are consistent with the estimated values based on the spectroscopic data. No appreciable differences in the structure parameters have been found between the results of analysis carried out on the basis of the Thomas-Fermi-Dirac and the relativistic Hartree-Fock-Slater scattering factors.
The Molecular Structure and Force Constants of Antimony Tribromide as Determined by Gas-phase Electron Diffraction
Authors: Konaka Shigehiro , Kimura Masao 
Published: July 2006

Abstract
The molecular structure and mean amplitudes of SbBr3 at 102°C have been determined by the sector-microphotometer method of gas-phase electron diffraction to be as follows: rg(Sb-Br)=2.490±0.003 Å, rg(Br-Br)=3.76±0.01 Å, θα=98.2°±0.6°, l(Sb–Br)=0.060±0.003 Å and l(Br–Br)=0.15±0.01 Å. General quadratic force constants have been determined from the observed mean amplitudes and vibrational frequencies. The molecular structure supports the validity of the empirical rules between a bond length and the covalent radii and electronegativities of its constituent atoms. An empirical equation, θ(YXY)=92+8xX−3xY(+xZ), has been proposed for the bond angles of Vb-group halides, (Z)XY3, and the electronegativities, x.
Polarographic Reductions of Alkaline Earth Metal Ions in Hexamethylphosphoramide. Effect of Cation of the Supporting Electrolyte
Authors: Izutsu Kosuke , Sakura Sachiko , Fujinaga Taitiro 
Published: July 2006

Abstract
Polarographic reductions of barium, strontium and calcium ions in hexamethylphosphoramide (HMPA) have been investigated in the supporting electrolytes of various perchlorates. The reduction of these alkaline earth metal ions are strongly influenced by the cation of the supporting electrolyte. When the size of the cation of the supporting electrolyte is small and easily adsorbed on the negatively charged electrode surface as in the cases of Me4N+ and Et4N+ ions, the reduction of the metal ions does not occur until that of the supporting electrolyte. The reduction becomes easier with the increase of cationic size. Thus, in Hex4NClO4 or LiClO4, these metal ions are reduced almost reversibly. These effects of the cation of the supporting electrolyte can be explained as electrode surface phenomena as in the reduction of alkali metal ions.
Study on Oxazolopyrimidines. VI. Formation of 3-Substituted Xanthines via 7(6H)-Iminooxazolopyrimidines
Authors: Ohtsuka Yozo 
Published: July 2006

Abstract
The condensation of several primary amines with 4-cyano-5-dialkoxymethylenaminooxazole gave 6-substituted 5-alkoxy-7(6H)-immooxazolo[5,4-d]pyrimidines. These compounds were converted into 3-substituted xanthines by treatment with aqueous alkali or by heating in formamide. The present reaction was compared with an analogous reaction, formation of 9-substituted hypoxantines via 7-aminooxazolo[5,4-d]pyridimine derivatives, and the difference in the reaction course was discussed in terms of the effect of substituents on the stability of oxazolopyrimidine intermediates.
The Jacobsen Reaction of Iodopseudocumenes and Related Compounds. Orientation in the Iodination of Halopseudocumenes
Authors: Suzuki Hitomi , Sugiyama Takashi 
Published: July 2006

Abstract
The Jacobsen reaction of iodopseudocumenes and related compounds was investigated. Both 3- and 5-iodopseudocumenes gave essentially the same product which consisted of 3,5-diiodopseudocumene (VI, 53%), 3,6-diiodopseudocumene (VII, 44%) and 5,6-diiodopseudocumene (VIII, 3%). The unexpected result was interpreted in terms of a mechanism involving a prior interconversion of the 3- and 5-iodo isomers followed by the ordinary process of aromatic disproportionation. 6-Iodopseudocumene gave VII as the major product. By prolonged contact with concentrated sulfuric acid, VI and VIII were found to undergo partial isomerization to give VII. Early structural assignment by Smith and Moyle for two diiodopseudocumenes was revised. Reactions of 4- and 5-iodohemimellitenes with sulfuric acid gave 4,6-diiodohemimellitene (XII) as the major product. A diiodohemimellitene melting at 114°C was found to be a mixture of XII and 4,5-diiodohemimellitene (XI), the former being predominant. Isomeric chloro-, bromo-, and iodopseudocumenes were iodinated with iodine-periodic acid dihydrate and the orientation in the products was determined.
Syntheses of Diiodo and Triiodo Derivatives of 1,2,3-Trimethylbenzene (Hemimellitene) and 1,2,4-Trimethylbenzene (Pseudocumene). A Convenient Use of Polyiodo Derivatives for the Characterization of Polyalkylbenzenes and Their Derivatives
Authors: Suzuki Hitomi , Haruta Yasuhiro 
Published: July 2006

Abstract
A complete set of diiodo and triiodo derivatives of 1,2,3-trimethylbenzene and 1,2,4-trimethylbenzene has been prepared and their physical properties are recorded. Use of polyiodo derivatives as a means for characterizing polyalkylbenzenes and their derivatives has been proposed.
Optically Active Triptycenes, V. Synthesis, Optical Resolution and Absolute Configuration of 2,7-Disubstituted Triptycenes.
Authors: Kuritani Masaaki , Sakata Yoshiteru , Ogura Fumio , Nakagawa Masazumi 
Published: July 2006

Abstract
2,7-Dicarboxytriptycene retaining C2-axis of symmetry was synthesized from 1,5-dichloroanthraquinone. Optical resolution of the triptycene afforded (+)- and (−)-enantiomers. The absolute configuration of (+)-2,7-dicarboxytriptycene was determined as 1R,6R by chemical correlation with (+)-2-methoxy-7-methoxycarbonyltriptycene which has 1R,6S configuration as confirmed by chemical transformation and X-ray structure analysis using the Bijvoet method. Starting from (+)-2,7-dicarboxytriptycene, a series of 2,7-disubstituted triptycenes having 1R,6R configuration has been prepared.
Optically Active Triptycenes. IV. Synthesis of Optically Active 2- or 5-Substituted 7-Carboxytriptycenes
Authors: Sakata Yoshiteru , Ogura Fumio , Nakagawa Masazumi 
Published: July 2006

Abstract
Starting from anthraquinone-1-carboxylic acid (I), 2-methoxy- and 5-methoxy-7-carboxytriptycenes (VIIa and VIIb) have been synthesized. Optical resolution of the triptycenecarboxylic acids with brucine afforded (+)-VIIa and (+)-VIIb. The absolute configuration of (+)-VIIa was determined to be 1R,6R by the chemical correlation with (+)-2,5-dimethoxy-7-methoxycarbonyltriptycene. From a comparison of the CD spectrum of (+)-5-methoxy-7-carboxytriptycene (VIIb) with that of (+)-2-acetoxy-5-methoxy-7-methoxycarbonyltriptycene (XIIIb), 1R,6R absolute configuration was assigned to (+)-VIIb. (+)-2-Hydroxy-5-phenylazo-7-carboxytriptycene (XIIa) was derived from (+)-VIIa. (+)-2-Chloro- and (+)-5-chloro-7-carboxy triptycenes (XVIIIa and XVIIIb) have been prepared from 5-chloro- and 8-chloro-1-carboxyanthraquinones (XIVa and XIVb). The absolute configuration of (+)-XVIIIa was determined to be 1R,6R by the chemical correlation with (−)-VIIa via (+)-2-chloro-5-methoxytriptycene (XIX).
The Ion-exchange Behavior of the Ammonium Ion on Crystalline Zirconium Phosphate
Authors: Hasegawa Yoshitsugu , Aoki Hisashi 
Published: July 2006

Abstract
The ion-exchange behavior of the ammonium ion on crystalline zirconium phosphate (c-ZrP) was studied by pH titration and X-ray powder diffraction. The ion-exchange capacity of c-ZrP was 4.4 meq/g in an acidic solution and 6.6 meq/g in an alkaline solution. At an exchange of 66% the Zr(NH4PO4)1.33(HPO4)0.67·H2O phase was present and at an exchange of 100% Zr(NH4PO4)2·H2O phase was present. The forward and backward titration curves exhibited a hysteresis loop. This results from the presence of the different phases in the titration of each direction. Through the ion-exchange cycle, the crystallinity of c-ZrP was maintained.
The Photochemistry of 2-Quinolinecarbonitriles. I. The Photochemical Reactions of 2-Quinolinecarbonitriles with Alcohols, Ethers, or Carboxylic Acids
Authors: Hata Norisuke , Ono Isao , Matono Satoru , Hirose Harutoshi 
Published: July 2006

Abstract
The photochemical reactions of 2-quinolinecarbonitriles with alcohols, diethyl ether, or aliphatic carboxylic acids in an atmosphere of oxygen or nitrogen were found to result in the replacement of the cyano group by 1-hydroxyalkyl, 1-ethoxyethyl, or alkyl group. However, the irradiation of 2-quinolinecarbonitrile in an alcoholic solvent except for the case of tert-butyl alcohol under a nitrogen atmosphere gave an unidentified substance (probably, a certain triazapentaphene) in addition to the photosubstitution product. The photoinduced substitution reaction found in the present experiment was revealed to proceed through the excited singlet state of 2-quinolinecarbonitrile, whereas the lowest triplet state was responsible for the formation of an unidentified substance in a deaerated alcohol.
Copper(II) Complexes of Histidine and Its Related Compounds in Aqueous Solutions
Authors: Aiba Hiroji , Yokoyama Akira , Tanaka Hisashi 
Published: July 2006

Abstract
The copper(II) complexes of histidine and its related compounds in aqueous solution were investigated by potentiometric, spectrophotometric, and magnetic methods. The presence of a diolated binuclear copper(II) complex was indicated in the 1 : 1 histamine-copper(II) system by quantitative analysis of the titration data and the antiferromagnetic character of the complex. The titration data could not be quantitatively interpreted owing to precipitation, but the formation of a similar diolated copper(II) complex was also shown in the 1 : 1 histidinecopper(II) system by the magnetic properties of the complex. From a comparison of the spectral properties of the pertinent complexes, it was shown for the neutral 2 : 1 histidine-copper(II) complex that histidine binds to copper(II) through the amino and imidazole groups in the chelate plane and through the carboxyl group in the apical position. In the copper(II) complexes of histidine and histamine, it was shown that ionization of the pyrrole nitrogen of the imidazole ring is promoted, causing a spectral blue shift.
X-Ray Photoelectron Spectroscopy of Oxine-Metal Chelates
Authors: Yoshida Tooru , Sawada Shigemasa 
Published: July 2006

Abstract
Photoelectron spectra of oxine-metal chelates were measured. The chemical shifts of the N(ls) electron binding energy were smaller than 0.7 eV. There were nearly linear relations between the chemical shifts and the electronegativities of metals or the partial ionic characters of the nitrogen-metal bonds of chelates.
Some Substituted 1H,4H- and 1H,5H-Pyrazolo[4,3-c]pyrazoles. Syntheses and Properties
Authors: Lee Joung Hee , Matsumoto Akira , Yoshida Masayuki , Simamura Osamu 
Published: July 2006

Abstract
1,4-Dimethyl-3,6-diphenyl-, 1,5-dimethyl-3,3-diphenyl-, and 4-methyl-2,3,6-triphenyl-pyrazolo[4,3-c]pyrazoles(IV, V, and VIII) were prepared and their structures were established on the basis of their spectral data.
Theoretical Calculation of the Carbon-13 Chemical Shifts of Some Normal Alkanes by the Linear Combination of Gauge Invariant Atomic Orbitals-Molecular Orbital Theory Using INDO and MINDO/2 Methods
Authors: Ando Isao , Nishioka Atsuo , Kondo Masahiro 
Published: July 2006

Abstract
The 13C chemical shifts of several n-alkanes (CH4, C2H6, C3H8, C4H10, C5H12, C6H14, and C7H16) were calculated using a linear combination of the gauge invariant atomic orbitals-molecular orbital theory of Pople and the INDO and MINDO/2 methods, and the results were compared with the experimental data reported by Grant et al. The calculated chemical-shift differences among the carbons in these molecules were found to agree with the observed data except in some cases, whereas the observed order of the chemical shift of the carbons in n-alkanes, which have more than two magnetically nonequivalent carbons, cannot be interpreted by means of the average excitation energy (ΔE) approximation. Histograms showing the distribution of the excitation energies from the occupied to unoccupied orbitais were obtained and compared with ΔE.
Bitter Principles of Isodon umbrosus Hara. The Structures of Umbrosin A and B
Authors: Kubo Isao , Kamikawa Tadao , Isobe Takahiko , Kubota Takashi 
Published: July 2006

Abstract
Two new ent-kaurene derivatives have been isolated from Isodon umbrosus Hara and formulated by spectroscopic and chemical evidence as structures (1) and (2), respectively. Antimicrobial activity has been tested.
The Microwave Spectra and r0, rs, and rm Structures of Ethylene Oxide
Authors: Hirose Chiaki 
Published: July 2006

Abstract
The rotational spectra of ten isotopic species of ethylene oxide, 12C2H416O, 12C13CH416O, 12C2H418O, 12C2H3D16O, cis- and trans-12C2H2D216O, 12C13CH2D216O, and 12C2H2D218O were observed. A least-squares fit including centrifugal distortion effect to the first order was made to derive the effective values of the A′, B′, C′, τ′aaaa, τ′bbbb, τ′cccc, and τ′aabb parameters and their correlation factors; τ′bbcc and τ′aacc were found to be insignificant. The rotational constants were used to determine the r0, rs, and rm structures. The structural parameters were derived as:
& r_0(CC)=1.470±0.003, r_s(CC)=1.466±0.002, r_m(CC)=1.462±0.003,
& r_0(CH)=1.085±0.004, r_s(CH)=1.085±0.001, r_m(CH)= 1.086±0.004,
& r_0(CO)=1.434±0.002, r_s(CO)=1.431±0.001, r_m(CO)=1.428±0.002,
& ∠_0HCH=116.28±0.69, ∠_SHGH=116.61±0.09, ∠_mHGH=116.92±0.69,
θ0=22.34±0.46, θs=21.99±0.11, θm=21.63±0.48 in units of Å and degrees; θ represents the angle of the H2C plane to the CC bond. The indicated error limits are 2.5 times the variances.
Kinetic Studies of the Reactions of the Ferricyanide Ion with Cobalt(II)-Aminopolycarboxylate Complexes
Authors: Ogino Hiroshi , Takahashi Masatake , Tanaka Nobuyuki 
Published: July 2006

Abstract
Kinetic studies of the reactions of the ferricyanide ion with cobalt(II)-aminopolycarboxylate complexes were carried out. The aminopolycarboxylates used in this study were trimethylenediaminetetraacetate (TRDTA), trans-1,2-cyclohexanediaminetetraacetate (CyDTA), propylenediaminetetraacetate(PDTA), and N-hydroxyethyl ethylenediaminetriacetate(HEDTA). The first step in the reaction is the rapid formation of a binuclear complex intermediate, [(ammopolycarboxylate)CoIIINCFeII(CN)5]n−(n=5 for TRDTA, CyDTA and PDTA and 4 for HEDTA), followed by the dissociation of the intermediate to ferrocyanide and Co(III)-aminopolycarboxylate ions. The equilibrium constant of the formation reaction and the rate constant of the dissociation reaction of the intermediate at an ionic strength of 0.66 were 6.2×102 M−1 and 2.0×10−2 s−1 respectively for the TRDTA system at 5 °C, 3.3×10 M−1 and 2.7×10−2 s−1 for the CyDTA system at 25 °C, and 2.4×103 M−1 and 3.0×10−3 s−1 for the PDTA system at 25 °C. The rate constant of the dissociation of [hedta CoIIINCFeII(CN)5]4− was found to be smaller than 1×10−4 s−1 at 25 °C and at an ionic strength of 0.66.