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Five new mixed ligand cobalt(III) complexes containing ethylenediamine(or R-propylenediamine)tetra(or tri)acetate and ethylenediamine have been obtained by the reactions of [Co(edta)]− and [Co(R-pdta)]− with ethylenediamine in water. The reactivity of these mixed complexes with ethylenediamine contradicts the mechanism of the reactions of [Co(edta)]− and [Co(pdta)]− with ethylenediamine proposed by Busch et.al.

Stoichiometric and kinetic investigations of reactions of the nitric and nitrous acids with hexaaquochromium(II) ions have been carried out in acidic media. The stoichiometries of these reactions found in this work were consistent with the mechanisms proposed by Swaddle,1) in which one mole of nitric acid reacts with four moles of chromium(II) and one mole of nitrous acid reacts with two moles of chromium(II). For the former reaction, it was found that the two-electron reduction of nitric acid by chromium(II) is rate-determining and that the rate constant was 2.2×102 M−1 s−1 at 25 °C and at an ionic strength of 1.0 (NaClO4). For the latter reaction, it was found that the one-electron reduction of nitrous acid by chromium(II) is rate-determining and that the rate constant was 4.5×10−3 M−1 s−1 at 25 °C and at an ionic strength of 1.0 (NaClO4). The rates of the reactions of chromium(II) with anionic species of the parent acids, NO3− and NO2−, were too slow to be detected under the present experimental condit...

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 dissocia...

Kinetic studies of the reactions between nitrate ions and Cr(II)–Y complexes, where Y represents cyclohexanediaminetetraacetic acid (CyDTA), trimethylenediaminetetraacetic acid (TRDTA), and N-(2-hydroxyethyl) ethylenediaminetriacetic acid (HEDTA), have been carried out. The reaction mechanisms of these complexes at the dropping mercury electrode were found to be expressed by the following equations:(Remark: Graphics omitted.)The formation constant, K, and the rate constants, k1 and k2, were determined in 0.1 M acetate buffer solutions of μ=0.5 by procedures including a curve-fitting method; the results were K=2.0×104 M−1, k1=0.55 M−1 s−1 and k2=2.8 M−1 s−1 for Cr(II)–CyDTA, K=2.4×10−5 M−1, k1=1.0×102 M−1 s−1, and k2

Polarographic reduction waves of In(III) in the presence of pentaammineiodo- or pentaammineisothiocyanatocobalt(III) complexes have been investigated. The catalytic effect on the electrode process of In(III) by iodide or thiocyanate ions which were liberated from the cobalt(II) complexes reduced simultaneously at the electrode was confirmed experimentally. A marked difference was found in the acceleration process between thiocyanate and iodide ions of these electrode reactions.

It has been confirmed experimentally that Cr(NH3)63+ gives a catalytic wave on its polarogram in the presence of EDTA and NO3− ions according to the EC(C′E′)n type mechanism; Cr(NH3)62+ which is produced on the electrode surface by the electrochemical reaction reacts with EDTA rapidly to form Cr(II)-EDTA (denoted as EC), which in turn gives a catalytic wave in the presence of NO3− ions (denoted as (C′E′)n). In addition, it was suggested that the reduction intermediates of nitrate ion oxidize Cr(H2O)p(NH3)6−p2+ at an appreciable rate, which nitrate ion itself does not.

A new method for the determination of association constants by the measurement of chronopotentiometric transition time has been developed and applied to the study on the outer-sphere association of some substitution-inert complex cations with sulphate ions. The association constants were determined from the change in transition time as function of the concentration of sulphate ions at ionic strength 0.1 (NaClO4) and 25° C: 93 ±8 for [Co(NH3)6]3+SO42−, 99 ±15 for [Co(en)3]3+SO42−, 61 ±7 for [Cr(NH3)6]3+SO42− and 58 ±8 for [Cr(en)3]3+SO42−. The ratios of the diffusion coefficients of the univalent ion-pairs and tervalent substitution-inert complex cations were also obtained. From these ratios the diffusion coefficients of the univalent ion-pairs were calculated, which were found to differ not greatly from those of univalent complex ions with similar structures.

Amperometric titrations of copper (II) and lead (II) have been carried out with ethylenediaminetetraacetate in acetate buffer of pH 4.2 containing 0.01% gelatin, using the dropping mercury electrode as an indicator electrode. Titrations were made at-0.12 volt vs. S. C. E.. for copper (II), and at-0.60 volt vs. S. C. E.. for lead (II). Accurate results were obtained with both elements in the concentration range of 5×10-4 to 1×10-2 mol/l.Potentiometric titrations at constant current have also been applied to the determination of 5×10-4 to 1×10-2 mol/l. of copper (II) and lead (II) with the same titrants and supporting electrolyte and with the dropping mercury electrode as an indicator electrode. A saturated calomel electrode was used for the reference electrode. As was predicted from the theoretical considerations, potential jumps occurred before the equivalence points in all titrations. The observed deviations were compared with the theoretically calculated deviations. The concentrations of copper (II) and lead (II) initially present in the solution (C in mol/l) can be calculated with the same equation as given in a previ ouspaper, C=iα-ir/k V+v/V+cv/V, where c represents the concentration of titrants expressed in mol/l.; V, the initial volume of the solution titrated in ml.; v, the volume in ml.required before the indicator electrode reaches the given potential (-0.12 volt vs. S. C. E.. for copper (II) and-0.60 volt vs. S. C. E.. for lead (II)) ; iα, the applied constant current expressed in microamperes; ir, the residual current in microamperes at the given potential for the observed end point; and k, the sensitivity of the electrode expressed in microampere/mol/l. The results indicate that the potentiometric titration at constant current is applicable with reasonable accuracy to the determination of copper (II) and lead (II) in concentrations down to 5×10-4 mol/l.

A typical reduction wave with a half wave potential of −0.462 V. vs. S. C. E. was obtained with nickel(II) ions in 6 M calcium chloride solution. The a. c. and the Kalousek’s polarograms revealed that the electrode reaction is a quasi-reversible one. From the coulometric measurement carried out at the constant potential, the overall electrode reaction proved to be a two-electron reduction. Nearly the total amount of nickel reduced by the controlled potential electrolysis with the mercury electrode was recovered from the mercury, indicating that the nickel (II) ions are reduced to nickel metal to form probably nickel amalgam. From these experimental results the electrode reaction of nickel (II) ions in 6 M calcium chloride at the mercury electrode was concluded to proceed quasireversibly according to the equationNicl_4^2-+2e+Hg\ightleftarrowsNi(Hg)+4Cl^

The ion association between trioxalatocobaltate(III) anion and uni-, bi- and tervalent cations in aqueous solutions has been studied by polarographic and ultraviolet, visible and infrared spectroscopic methods. The association constants have been obtained by the measurement of the polarographic diffusion current of trioxalatocobaltate(III) ions in the presence of varied concentrations of cations at ionic strength 0.1 (NH4NO3) and 25°C. The influence of ammonium ion was taken into consideration in the treatment of polarographic data. The values obtained are 7.9 for (CH3)4N+[Co(ox)3]3−, 3.7±0.4 for (C2H5)4N+[Co(ox)3]3−, 22±1 for Na+[Co(ox)3]3−, 56±6 for Mg2+[Co-(ox)3]3−, 55±4 for Ca2+[Co(ox)3]3−, 53±3 for Sr2+[Co(ox)3]3−, 55±7 for Ba2+[Co(ox)3]3− and 118±17 for Al3+[Co(ox)3]3−. The association constant of NH4+[Co(ox)3]3− was determined by the conductivity measurement to be 33.6 (logK=1.53) at zero ionic strength. No change was observed in the visible, the ultraviolet and the infrared absorption spectra of t...

The reduction of hexamminechromium(III) ions at the dropping mercury electrode has been studied chronopotentiometrically in acetate buffer solutions. The electrolysis at constant cathodic current gives a well-defined chronopotentiogram which corresponds to the one-electron reduction of chromium(III) to chromium(II), but the anodic chronopotentiogram which is obtained by the electrolysis at constant anodic current is clearly separated from the cathodic one. A general treatment for a chronopotentiometric potential-time curve for the electrode process with the following chemical reaction has been developed by the application of Lagrange’s theorem. The results indicate that hexamminechromium(III) ions are irreversibly reduced at the dropping mercury electrode without any preceding chemical reactions prior to the more or less irreversible electron-transfer process, followed by the rapid aquation of the reduced species.

Kinetic parameters of electrode reactions are collected from the literature and tabulated.

The rate of the electron-transfer reactions between ethylenediaminetetraacetatochromate(II) and some acidopentaamminechromium(III), CrX(NH3)52+, has been measured at ionic strength 1.0 (NaClO4). The rate constants (l mol−1sec−1) for X=F−, Cl−, Br− and OH− are 2.07 at 25°C, >2×103 at 25°C, 2×103 at 15°C and 2.4×102 at 25°C, respectively. These reactions produce ethylenediaminetetraacetatochromate(III) ions which do not contain an anion X. The mechanisms of these reactions are discussed.

The dissociation reaction of nitrilotriacetatocadmate(II) complexes has been investigated polarographically and chronopotentiometrically in the presence and the absence of acetate ions. The results indicate that the treatment reported by Koryta for the effect of acetate ion on the kinetic current is appropriate. The rate constant of the dissociation reaction of nitrilotriacetatocadmate(II) complexes is a function of hydrogen ion concentration and expressed as k=3.4+2.5×105[H+]+2×108[H+]2 at 25°C.

The formation constants of acetatocadmium-(II) and acetatocobalt(II) complexes were determined at ionic strength of 0.2 at 15, 25 and 35°C with the procedure that is based on the polarographic measurement of the sum of the equilibrium concentrations of the hydrated metal ions and the metal acetate complexes in the substitution reaction involving EDTA complexes. The resulting formation constants KCdOAc and KCoOAc are 27 and 2.1 at 15°C, 16 and 0.6 at 25°C and 20 and 0.6 at 35°C, respectively.

The reduction process of indium(III) at the dropping mercury electrode in thiocyanate solutions has been investigated by direct current polarography, alternating current polaro-graphy and faradaic impedance measurements. The reduction current in the potential region between −0.5 to −0.9 V. vs. saturated calomel electrode is greatly increased by the addition of minute amounts of thiocyanate ions, when a remarkable minimum is observed on the diffusion current plateau at relatively negative potentials. On the alternating current polarogram, indium(III) in a potassium thiocyanate solution gives a negative admittance in the potential region where the minimum appears on the direct current polorogram. The analysis of impedance measurements has shown that the resistance component has a negative value in that potential region. The experimental results have been explained by assuming that the overall electrode process is composed of two simultaneous reactions, one of which proceeds at the naked electrode surface, a...

The reduction of hexamminechromium(III) ion at the dropping mercury electrode has been studied in neutral and acid aqueous solutions. Hexamminechromium(III) ion gives no well-defined d. c. polarographic wave in an unbuffered neutral solution, whereas in an acid solution it gives a well-defined two-step wave, the first wave corresponding to the reduction of chromium(III) to chromium(II) and the second, to that of chromium(II) to chromium-(0).The first wave of the d. c. polarogram obtained in an acid solution is diffusion-controlled and gives a slope of the log-plot close to that expected for a reversible wave. The a. c. and the Kalousek polarogram, however, are of the irreversible type. No chemical reaction involving hydrogen ions, ammonium ions or ammonia takes place preceding the electron transfer. Considering these results, the following mechanism is temporarily suggested for the reduction of hexamminechromium(III) ions at the dropping mercury electrode:[Cr(NH3)6]3++e\ightleftarrows[Cr(NH3)6]2+[Cr(NH3)6...

Kinetics of electron-transfer reactions of ethylenediaminetetraacetatochromate(II) ions with some isothiocyanatoammine complexes of chromium (III), Cr(NCS)n(NH3)6−n(3−n)+(n=0, 1,4 and 6) have been studied. The former ions are present in the forms of both CrII(H2O)edta2− and CrII(H2O)Hedta−, but the reaction of CrII(H2O)Hedta− with Cr(NCS)n(NH3)6−n(3−n)+ is not significant in the pH range from 3.6 to 5.3. Second-order rate constants (l mol−1sec−1) of the reactions between CrII(H2O)edta2− and Cr(NCS)n(NH3)6−n(3−n)+ at ionic strength 1.0 and 25°C are

A new procedure for the determination of the formation constants of metal acetate complexes was developed. The procedure is based on the polarographic measurements of the sum of the equilibrium concentrations of the hydrated metal ions and the metal acetate complexes in the presence of an appropriate auxiliary complex forming substance and of the reference metal ions of which the formation constants of acetate complexes are known.The procedure was applied to the study of acetatocopper(II), acetatolead(II) and acetatozinc(II) complexes, EDTA being used as an auxiliary complex forming substance. The overall formation constants KM(OAc)n (n=1 and 2) for these metal acetate complexes were determined at an ionic strength of 0.2 at 15, 25 and 35°C.

A theoretical treatment of the potentiostatic and the modified galvanostatic method for fast electrode reactions has been developed. A general relationship between current and potential is derived and procedures to determine the kinetic parameters of electrode reactions are established, when the Levich and the Frumkin corrections for the effect of the electrical double layer are considered. The dependence of the measured standard rate constant and the measured transfer coefficient on the double layer structure is also clarified. The procedures are applied to electrode reactions of some simple and complex metal ions to obtain the kinetic parameters corrected for the effect of double layer.

The polarographic method for the determination of the formation constants which is based on the measurement of the effects of acetate and/or other co-existing ions on the equilibrium of the substitution reaction, M+M′L\ightleftarrowsML+M′, has been developed, and applied to the study of the copper(II) complexes with acetate and/or sulfate ions. The formation constants obtained at 25°C and ionic strength 1.0 are: 2·0×10 for KCu(OAc), 1·1×102 for KCu(OAc)2, < 3 for KCuSO4, ∼3×10 for KCu(SO4)2, 4×10 for KCu(OAc)(so4) and ∼7×10 for KCu(OAc)(SO4)2.

Kinetics of the thermal decomposition reactions of [Cr(NH3)6]X3 (X=Br, I and NCS) and [Cr(NCS)(NH3)5](NCS)2 in solid state were studied by the manometric method. The rate constants, activation energies and activation entropies of the substitution reactions of outer-sphere anions for coordinated ammonia molecules were presented, and possible reaction mechanisms were discussed.

The polarographic diffusion current of some tervalent substitution-inert complex cations decreases by the addition of sulfate. From the change in diffusion current the association constants of substitution-inert complex and sulfate ions are obtained at ionic strength 0.1 (NaClO4) and 25°C. The values are 69±8, 58±8 and 4×10 for [Co(NH3)6]3+–SO42−, [Cr(NH3)6]3+–SO42− and [Cr(H2O)6]3+–SO42 respectively. The formation of [Co(NH3)6]3+–HSO4− is negligibly small compared with that of [Co(NH3)6]3+–SO42−.

The thermal shrinkage of fibrous homopolymers and copolymers by the partial melting of crystalline regions may be understood theoretically on the basis of the theories on melting in homo- and copolymers as described in our preceding papers.The purpose of this work is to investigate the thermal shrinkage of fibrous substantial copolymers by appling the relation between the relative shrinkage and the absolute temperature derived from the theories on melting in copolymers composed of units of type A capable of crystallizing and other units B incapable of crystallizing proposed in our preceding papers.It may be assumed that the thermal shrinkage curves of fibrous copolymers show some features differing from the shrinkage curves of fibrous homopolymers because the dependence of the crystallinity to temperature is characteristic for copolymers especially.The fibrous samples used are polyethylene terephthalate/isophthalate copolymer fibers, with which the thermal shrinkage curves were discussed from a stand point as mentioned above in comparison with the results of DTA.

The SGF MO’s for the π-electron system of 1,10-phenanthroline have been determined by following the Pariser-Parr-Pople’s treatment. For the description of the lower excited states, the configuration interaction among nineteen singly-excited configurations with lower energy has been taken into account. The electronic spectrum of 1,10-phenanthroline has been interpreted on the basis of the results of the theoretical calculation. The SCF MO’s for the π-electron system of a coordinated 1,10-phenanthroline in the tris-iron(II) complex have been determined to be self-consistent under the electrostatic potential field of the central metal ion and the other ligand molecules. On the basis of the results for coordinated ligand, the π-electronic structure of tris-(1,10-phenanthroline)iron(II) ion has been investigated from the theoretical point of view. It has been shown that two kinds of the charge-transfer transitions are responsible for an intense absorption band in the visible region, namely electron transfers f...

A new method for the determination of the formation constants of metal acetate complexes has been developed. The method is based on the polarographic measurement of the sum of the equilibrium concentrations of hydrated metal ions and metal acetate complexes in the presence of an appropriate auxiliary complex-form-ing substance. One of the advantages of the method is that no estimation is required in the course of the calculation. The other is that no information of the dissociation and formation constants is required concerning the auxiliary complex-forming substance.The method is applied to the study of acetatonickel(II) complexes using nitrilo-triacetate as an auxiliary ccmplex-forming substance. The results reveal that only monoacetatonickel (II) ions, NioAc+, exist in the solution containing acetate up to 0.2M in concentration. The formation constants KNiOAc at ionic strength 0.2 are caluclated to be 2.6 at 15°C and 2.4 at 35°C.

The proton magnetic resonance spectra of three kinds of tris(α-diimine)iron(II) complexes, i.e., tris(glyoxal-bis-N-methylimine)-, tris-(biacetyl-bis-N-methylimine)- and tris(biacetyl-bis-N-butylimine)iron(II) complexes, were measured. Remarkable and significant shifts of the NMR signal of some protons in tris(α-diimine)iron(II) complexes were observed, which provide the support for the delocalized nature of π-electron system on the chelate ring and may be considered as evidence for the existence of a ring current in the chelate. The stereochemistry of tris(biacetyl-bis-N-butylimine)iron(II) complex was discussed on the basis of the results of NMR spin-decoupling experiments.

Kinetic parameters of the electrode reaction of ethylenediaminetetraacetatoaquochromate-(III)/ethylenediaminetetraacetatoaquochromate(II) at the dropping mercury electrode have been determined by the potentiostatic method in sodium chloride solutions of ionic strength 0.5 containing 0.1 M acetate buffer. The measured standard rate constant (ks)ms is 2.1×10−1cm sec−1 and the measured transfer coefficients (αc)ms and (αa)ms are 0.58 for the cathodic and 0.39 for the anodic process. The correction for the effect of the electrical double layer has been made on these parameters. The values obtained are: (ks)corrc=1.7×10 cm sec−1, (αc)corr=0.54 and (αa)corr=0.43. The standard potential −1.220 V vs. SCE determined by the potentiostatic method is compared with −1.218 V vs. SCE obtained by the measurement of the equilibrium potential. These values are in good agreement within the experimental error.

The complex-forming reaction of nickel (II) with ethylenediaminetetraacetate (EDTA) was found to proceed in acetate buffers of pH 3.8 to 5.2 through four different reaction paths,Ni2++HY3− \xrightarrowk1a NiHY−NiOAc++HY3− \xrightarrowk1b NiHY−+OAc−NiHY− \ightleftarrows NiY2−+H+Ni2++H2Y2− \xrightarrowk2a NiH2YNiOAc++H2Y2− \xrightarrowk2a NiH2Y+OAc−NiH2Y \ightleftarrows NiHY−+H+ \ightleftarrows NiY2−+2H+The change in the polarographic diffusion current of nickel(II) at the rotated dropping mercury electrode was utilized to follow the decrease of the nickel(II) concentration in the reaction mixture after the initiation of the reaction. The rate constants of the reaction paths were determined at 0°C and ionic strength 0.2, with the results:k1a=1.06×104 mol−1 liter sec−1k1b=2.25×104 ”k2a=2.04×102 ”k2b=6.04×102 ”These constants are much smaller than those of the corresponding reactions between copper(II) and EDTA.

As the representative theories on melting in copolymers composed of units of type A capable of crystallizing and other units B incapable of crystallizing, two theories proposed by P. J. Flory in 1949 and in 1955 are known well. However, there are not a few experimental results on melting in copolymers that can not be explained enough even with those theories. Above all, the causes of the discrepancy between numerical values of the heat of fusion derived from melting point depression in polymer A-diluent system and from melting point data in copolymer A-B has not been clarified strictly as yet.The purpose of this work is to investigate theoretically this problem by taking into consideration the conformational entropy of amorphous chains for copolymers composed of units of type A and other units B.Thus, some thermodynamic expressions were derived for melting in copolymer systems. The results obtained affords fair explanations for discrepancy between numerical values of the heat of fusion previously derived from melting point depression in polymer A-diluent system and from melting point data in copolymer A-B.

The reduction of a series of isothiocyanato-ammine chromium(III) complexes [Cr(NCS)p-(NH3)6−p](3−p)+ at the dropping mercury electrode has been studied. The direct current, the alternating current and the Kalousek polarograms of these complexes have been measured in various supporting electrolyte solutions. The nature of the reduction waves, corresponding to the one-electron reduction of chromium(III) to chromium(II), has been discussed.

Compton scattering of optical photons on 6.0-GeV electrons has been observed at the Cambridge Electron Accelerator. A giant-pulsed ruby-laser burst of 0.2 J, impinging upon a 2-mA circulating electron current, was observed to yield about 8 scattered photons per pulse. These photons acquire, through a twofold Doppler shift, energies of hundred of MeV, and are expected to retain to a high degree the polarization of the laser beam. The observed yield is compatible with predictions based upon the theory of Compton scattering.

The kinetic study of the substitution reaction of copper(II) ions and zinc(II)-nitrilotriacetate complexes in acetate buffer solutions has been carried out with the same procedure as reported previously. The reaction was treated as to proceed through both hydrated metal ions and monoacetato complexes. The rate constants for eight elementary reaction paths, of which four involve the hydrated copper(II) ions and the others the monoacetatocopper(II) complexes, were determined at ionic strength 0.23 at 0°C. The values obtained indicate that all the reactions proceeding through hydrated copper(II) ions are faster than the corresponding reactions proceeding through monoacetatocopper(II) complexes.

The current-potential curves of some substitution-inert complex ions are affected by the change in the composition of the supporting electrolyte. The change in the one-electron reduction wave of hexaquochromium(III) ions with the increase in the concentration of sodium perchlorate and sodium iodide is analyzed in terms of the effect of the structure of the electrical double layer. The addition of sodium sulfate at a constant ionic strength of 0.1 shifts the half-wave potentials of hexaquochromium(III), hexamminechromium(III) and hexamminecobalt(III) ions to more negative potentials. In the case of hexamminecobalt(III), the shift is much greater than in the cases of the former two complex ions. These phenomena are interpreted to be due to the effects of the double layer structure and of the ion association.

The thermodynamic dissociation constants of 2-carboxytropone, 3-carboxytropolone, 4-carboxytropolone, 5-carboxytropolone, 3-carboxy-4-methyltropolone, 3-carboxymethyltropolone, 3,4-dicarboxytropolone and 3-carboxy-4-carboxymethyltropolone have been determined by means of the pH titration with a glass electrode. The relationships between the magnitudes of the dissociation constants and the structures of these compounds have been discussed.

The formation constants of dithiocyanatomercury(II) and tri- and tetrathiocyanatomercurate(II) complexes have been determined by the potentiometric method with a dropping mercury electrode at ionic strength 0.2 and at 15, 25 and 35°C. The values obtained are:at 15°C, KHg(SCN)2c=1.8×1017, KHg(SCN)3c=7.1×1019, KHg(SCN)4c=1.11×1022;at 25°C, KHg(SCN)2c=2.7×1016, KHg(SCN)3c=1.39×1019, KHg(SCN)4c=1.32×1021;at 35°C, KHg(SCN)2c=5.5×1015, KHg(SCN)3c=2.43×1018, KHg(SCN)4c=1.68×1020.The thermodynamic formation constants of these complexes and the free energy change, the enthalpy change and the entropy change of the formation reactions of these complexes have been calculated.

Conformation of trimethylenediaminetetraacetatocobaltate(III) (Cotrdta−) was inferred from the measurement of proton nuclear magnetic resonance spectra. It was found that K[Co-trdta]·2H2O crystals are mixtures consisting of equimolar amounts of the crystals of K[(+)546-Cotrdta]·2H2O and those of K[(−)546Cotrdta]·2H2O; that is, so-called “spontaneous resolution” was found. The absolute configuration of optically active Cotrdta was determined by the measurements of optical rotatory dispersion (ORD) and circular dichroism (CD) curves and by the reaction with ethylenediamine to form tris(ethylenediamine) cobalt(III) cation.