A Five-Membered PdSbn Coordination Series

Abstract

Five complexes of the general formula PdCl2(SbMe2Cl)n (n = 1-5) have been synthesized by combining [PdCl2(MeCN)2] and SbMe2Cl in different molar ratios in toluene. Their solid-state structures have been determined by X-ray crystallography. The complexes display considerable structural diversity: [Pd4Cl8(SbMe2Cl)4] (1, n = 1) is a chloride-bridged tetramer; [Pd2Cl4(SbMe2Cl)4] (2, n = 2) is a dimer; [PdCl(SbMe2Cl)2(SbMe2Cl2)] (3, n = 3) is a supramolecular polymer; [Pd2(SbMe2Cl)8]Cl4 (4, n = 4) is a loosely associated dimer, and [Pd(SbMe2Cl)5]Cl2 (5, n = 5) is a monomer with square-pyramidal PdSb5 coordination geometry. Each structure contains secondary interactions between coordinated Sb centers and chloride ligands or anions, resulting in five-coordinate Sb in all cases with a range of Sb···Cl bond lengths. The electronic structures of these complexes have been investigated using DFT methods including NBO and Pipek-Mezey localized orbital methods in order to interrogate both the Sb-Pd and secondary Sb···Cl bonding.