A Five-Membered PdSbn Coordination Series

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.