Study of the structure and reactions of bis(mu-oxalato)tetramminediplatinum(II) in aqueous chloride solutions

A comparison study of the bis(mu -oxalato)tetramminediplatinum(II) dimer [P t-2(NH3)(4)(mu -C2O4)(2)] and the oxalatodiammineplatinum(II) chelate [Pt(N H3)(2)C2O4] is performed. The kinetics and mechanism of substitution of C2O 42- for Cl- in aqueous chloride solutions are studied by photoelectronic sp ectroscopy, gravimetry, and chemical phase analysis within the 1.0-6.7 pH r ange at 75 degreesC. The rate constants of substitution and the equilibrium constants for a two-step protonation for the dimeric and chelate complexes are calculated. Their solubility in 1 M KCl at 75 degreesC is determined. The unit cell parameters for [Pt-2(NH3)(4)(mu -C2O4)(2)] are determined: a = 3.858 Angstrom, b = 10.704 Angstrom, c = 6.795 Angstrom, beta = 94.35 deg rees. The IR spectra of [Pt(NH3)(2)C2O4], [Pt-2(NH3)(4)(mu -C2O4)(2)], and their deuterated analogs are studied.