Inorganic Chemistry, Vol.33, No.12, 2645-2650, 1994
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-dodecaborane 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 charge which greatly enhances their coordinating capabilities. As a consequence, the dithio closo derivatives which are neutral dithioethers, and hence weak ligands, tend to modify themselves upon coordination, losing a boron atom and becoming anionic, to produce the strongly coordinating 7,8-dithio-7,8-dicarba-nido-undecaborate(1-) derivative ligands. The B+ removal has been proven by the X-ray analysis of the resulting [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 P1BAR, 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 = 84.64(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) angstrom, beta = 108.73(3)degrees, R(w)(F(o)) = 0.077.