Journal of Inorganic and Nuclear Chemistry最新文献

The formation constants of uracil, uridine and thymidine with [Pd(dien)(OH₂)]²⁺ and [Pd(en)(OH₂)₂]²⁺ where dien = diethylenetriamine and en = ethylenediamine, have been determined potentiometrically at I = 0.5 mol dm⁻³ KNO₃ and 25°C. The equilibria between [Pd(dien)(OH₂)]²⁺ and these ligands may be described by $\text{[}\text{Pd(dien)(OH}{}_2\text{)}\text{]}{}^{\mathrm{2+}}\text{+}\text{L}{}^{\mathrm{-}}\text{⇌}\text{K}\text{[}\text{Pd(dien)L}\text{]}{}^{\mathrm{+}}$ where L⁻=anionic form of uracil, uridine or thymidine. Log K values for uracil, uridine and thymidine complexes are 8.01 ± 0.01, 8.08 ± 0.01 and 8.31 ± 0.01 respectively.

The equilibria between [Pd(en)(OH₂)₂]²⁺ and these ligands are $\text{[}\text{Pd(dien)}\text{(}\text{OH}{}_2\text{)}{}_2\text{]}{}^{\mathrm{2+}}\text{+ L}{}^{\mathrm{minus;}}\text{⇌}\text{K}{}_1\text{[}\text{Pd(en)(OH}{}_2\text{)L}\text{]}{}^{\mathrm{+}}\text{+ H}\text{2}\text{O}$$\text{[}\text{Pd(dien)}\text{(}\text{OH}{}_2\text{)L]}{}^{\mathrm{+}}\text{+ L}{}^{\mathrm{minus;}}\text{⇌}\text{K}{}_2\text{[}\text{Pd(en)L}{}_2\text{] + H}\text{2}\text{O}$ with log K₁ 8.59±0.01, 8.65±0.01 and 8.84±0.01 and log K₂ = 6.79±0.01, 5.92±0.01, and 5.85±0.01 respectively for uracil, uridine and thymidine, The species distributions at different pH and the mode of coordinations are discussed in relation to these values.

A new method for the synthesis of NF₄⁺ salts is reported. It permits the synthesis of otherwise inaccessible salts derived from nonvolatile Lewis acids which do not possess HF-soluble cesium salts. The method was successfully applied to the synthesis of the novel salt NF₄⁺UF₅O⁻. This compound is a yellow solid, stable at room temperature. It was characterized by analysis and vibrational spectroscopy.

The synergistic extraction of U(VI) from aqueous nitric acid by mixtures of HTTA and TBP was studied to establish the presence of mixed ligand species, using a method-developed in this laboratory. The results obtained by this method were corroborated with the conventional extraction studies. It was established that the species UO₂(NO₃)(TTA)TBP reported in the literature was not involved in the synergistic extraction and that the only species responsible for synergism was UO₂(TTA)₂·TBP. Equilibrium constants for various equilibria involved are calculated.

The kinetics of the bromide interchange and base hydrolysis of trans-(Rh(tn)₂Cl₂)⁺, (tn=propane-1,3-diamine) have been studied. For the bromide interchange the observed pseudo first order rate constant is independent of bromide ion concentration up to 0.2 mol dm⁻³, whereas for the base hydrolysis the observed pseudo first order rate constant is given by k_obs = k₁ + k₂(OH⁻) for hydroxide ion concentrations up to 1.0 mol dm⁻³.

The activation parameters for these two reactions have been determined and are compared with those for similar reactions of other analogous complexes.

Complexes of Bi(III) with oxydiacetic and thiodiacetic acids were studied in aqueous solution by UV spectrophotometry. In acidic medium, with oxydiacetic acid 1 : 1, 1 : 2 and 1 : 3 (metal to ligand) mononuclear complexes were found and formation constants calculated at 25°C in 0.5 M (Na, H)ClO₄ medium. By using the protonation constants of the ligand, determined under the same experimental conditions, the following equilibrium constants can be calculated (L²⁻ is the anion of the acid): $\text{Bi}{}^{\mathrm{3+}}\text{+ L}{}^{\mathrm{2-}}\text{⇋BiL}{}^{\mathrm{+}}\text{log}\text{β}{}_{101}\text{= 7.69}$$\text{Bi}{}^{\mathrm{3+}}\text{+ 2L}{}^{\mathrm{2-}}\text{⇋BiL}{}^{\mathrm{-}}{}_2\text{log}\text{β}{}_{102}\text{= 12.73}$$\text{Bi}{}^{\mathrm{3+}}\text{+ 3L}{}^{\mathrm{2-}}\text{⇋BiL}{}^{\mathrm{3-}}{}_3\text{log}\text{β}{}_{103}\text{= 16.19}$ With thiodiacetic acid only a 1 : 1 species was found, the stability of which is less than of the corresponding complex with oxydiacetic acid.

Mixed complexes of Zn(II) with chiral aminoacids and 1,10-phenanthroline have been prepared and their C.D. and O.R.D. spectra measured. All the C.D. spectra exhibited an exciton splitting at 268 nm and their intensities depended on the chiral ligand. These results were interpreted in terms of steric effects through the exciton theory.