INDIUM COMPOUNDS THAT CONTAIN 2 DIFFERENT ORGANIC SUBSTITUENTS - CRYSTAL-STRUCTURE OF [IN(CH2CME3)(CH2SIME3)CL]2 - AN INTERESTING CASE OF PARTIAL LIGAND DISORDER IN THE SOLID-STATE

Three new indium compounds containing two different organic substituents, In(CH2CMe3)(CH2SiMe3)Cl, In(CH2CMe3)(C6H5)Cl, and (Me3CCH2)(Me3SiCH2)InPEt2, have been prepared, purified, and characterized. All compounds were characterized by partial elemental analysis (C, H, and P as appropriate), cryoscopic molecular weight studies in benzene solution, and NMR and IR spectroscopic studies. All compounds exist as dimeric molecules in solution. NMR spectral data were consistent with the presence of mixtures of cis and trans isomers in solution. [In(CH2CMe3)(CH2SiMe3)Cl]2 crystallizes in the centrosymmetric triclinic space group P1BAR (C(i)1, No. 2) with a = 6.1000 (10) angstrom, b = 10.337 (3) angstrom, c = 12.190 (3) angstrom, alpha = 77.28 (2)-degrees, beta = 84.41 (2)-degrees, gamma = 84.50 (2)-degrees, V = 744.0 (3) angstrom 3, and Z = 1. Diffraction data (Mo K-alpha, 2-theta = 5-50-degrees) were collected on a Siemens R3m/V automated four-circle diffractometer, and the structure was solved and refined to R = 5.39% and R(w) = 7.65% for those 1752 unique data with \F(o)\ > 4-sigma(\F(o)\) (R = 8.30% for all 2629 data). Distances within the centrosymmetric dimeric molecule in the trans conformation include In-CH2CMe3 = 2.140 (13) angstrom, In-CH2SiMe3 = 2.125 (12) angstrom, and In-Cl (bridging) = 2.572 (3) and 2.659 (3) angstrom. There is some slight disorder of CH2CMe3 and CH2SiMe3 ligands (approximately 73%:27%), and there are weak intermolecular In...Cl interactions at 3.528 (3) angstrom along the a-direction. Attempts to prepare the related organogallium compounds, Ga(Me)(CH2CMe3)Cl and Ga(CH2CMe3)(CH2CMe2Ph)Cl, were unsuccessful. Ligand redistribution reactions led to the formation and subsequent isolation of mixtures of the appropriate symmetrized products.