NIDO-CARBORANE-CONTAINING COMPOUNDS RESULTING FROM THE REACTION OF CLOSO-CARBORANES WITH TRANSITION-METAL COMPLEXES

The reaction of closo derivatives of 1,2-dithio-1,2-dicarba-closo-dode caborane with [MCl(PPh3)2] (M = Cu, Ag) in ethanol, produces complexes of the corresponding nido derivatives of 7,8-dithio-7,8-dicarba-nido- undecaborate-(1). These nido ligands form via formal B+ elimination in the closo precursors, becoming anionic, i.e., they have a negative ch arge which greatly enhances their coordinating capabilities. As a cons equence, the dithio closo derivatives which are neutral dithioethers, and hence weak ligands, tend to modify themselves upon coordination, l osing a boron atom and becoming anionic, to produce the strongly coord inating 7,8-dithio-7,8-dicarba-nido-undecaborate(1-) derivative ligand s. The B+ removal has been proven by the X-ray analysis of the resulti ng [Cu{7,8-mu-S(CH2CH2OCH2CH2OCH2CH2)SC2B9H10}(PPh3)] and [Ag{7,8-mu-S (CH2CH2OCH2CH2)SC2B9H10}(PPh3)]. Crystal structure data for Cu{7,8-mu- S(CH2CH2OCH2CH2OCH2CH2)SC2B9H10}(PPh3)1: mol wt 637.5; space group P1B AR, Z = 2; a = 10.880(3) angstrom, b = 12.784(3) angstrom, c = 13.707( 5) angstrom, alpha = 64.31(2)degree, beta = 68.09(2)degrees, gamma = 8 4.64(2)degrees R(w)(F(o)) = 0.061. Crystal structure data for [Ag{7,8- mu-S(CH2CH2OCH2CH2)SC2B9H10}(PPh3)]mol wt 637.8, space group P2(1)/n; Z = 8; a = 14.578(9) angstrom, b = 23.557(9) angstrom, c = 18.322(6) a ngstrom, beta = 108.73(3)degrees, R(w)(F(o)) = 0.077.