I. Cis-dichlorodiammineplatinum(II). Aquation equilibria and isotopic exchange of chloride ligands with free chloride and tetrachloroplatinate(II). II. The Szilard--Chalmers effect in solid-state systems containing the octa-μ3-chloro-octahedro-hexamolybdenum(II) cluster

A titration technique was utilized to determine the equilibrium quotients for the first and second aquation steps of cis-Pt(NH3)2Cl2. At 25.00C and an ionic strength of 0.318 M the first and second aquation equilibrium constants are: K1 = 3.63 +- 0.22 x 10-3 M, ΔH10 = 3.4 kcal and K2 = 1.11 +- 0.14 x 10-4 M, ΔH20 = 10 kcal. In the ternary system, cis-Pt(NH3)2Cl2:PtCl42-:Cl-, the kinetics of isotopic exchange of chlorine was investigated. In addition to the expected route of exchange via aquation, a direct exchange of chlorine ligands between cis-Pt(NH3)2Cl2 and PtCl42- occurred which is described by the rate expression. Separation procedures were devised for partial resolution of component yields resulting from dissolving a neutron-irradiated sample of (H3O)2[(Mo6Cl8)Cl6] . 6H2O in 1.5 N HCl. A recrystallization procedure was formulated to determine the retention of activity in the parent compound of molybdenum(II) chloride clusters after neutron irradiation. The retention found in an aqueous 1.5 N HCl solution containing 1 percent (H3O)2[(Mo6Cl8)Cl6] . 6H2O is 0.64 percent. For a solid sample of (H3O)2 [(Mo6Cl8)Cl6] . 6H2O aged 24 hours in Dry Ice after neutron irradiation, a retention of 7.0 percent was observed. Under the same conditions, a sample of (Mo6Cl8)Cl4 with 0.8 percent and 2.7 percent water had retentions of 25.0 percent and 11.1 percent, respectively. Effects of thermal annealing and gamma ray treatment on solid samples of [(Mo6Cl8)Cl4] . 2H2O were investigated