Synthesis and Coordination Chemistry of a Chelating P-Sn Ligand Based on Stanna- closo-dodecaborate.

Substitution at a B-H unit of the heteroborate cluster stanna- closo-dodecaborate [SnB11H11]2- at the upper belt of the icosahedron by one of the triarylphosphine moieties of xantphos was carried out under the catalysis of palladium acetate. The resulting coupling product is a monoanion offering two coordination sites: a low-valent tin-cluster vertex and a triaryl phosphine moiety. The basicity and nucleophilicity of the anion were investigated in reactions with a strong acid or an alkylating agent. Transition-metal electrophiles like platinum halide PtCl2 or rhodium carbonyl [Rh(CO)2Cl]2 react with the bidentate ligand, with the formation of cis-coordination products. [ABSTRACT FROM AUTHOR]