Some tritertiary arsine complexes of nickel, palladium, and platinum

Abstract

A series of complexes of composition M(ttas)X₂[ttas = bis-(o-dimethylarsinophenyl)methylarsine; M = Ni; X = Cl, Br, I, SCN; M = Pd, Pt; X = Cl, Br, I] have been prepared and characterised in the solid state and in solution. The Pd and Pt complexes are generally 1 : 1 electrolytes indicating a four-co-ordinate geometry but there is a slight tendency towards association under certain circumstances. The Ni^II analogues are very sensitive to the nature of X and the solvent. Five-co-ordinate monomers are favoured and are most likely in non-polar solvents. Hydroxylic solvents favour disproportionation to [Ni(ttas)₂]²⁺ and either NiX₄^2– or its solvolysis products. A series of complexes of the type M(ttas)₂Y₂(M = Ni; Y = ClO₄^–, NO₃^–, I^–; M = Pd, Pt; Y = ClO₄) have also been described but the assignment in terms of a six-co-ordinate M is in doubt. An octahedral Ni^III complex mer-[Ni(ttas)Br₃] is also described.