Molecular structures of trimeric diphenyltin chalcogenides, (Ph2SnE)3, E=S, Se, Te

The trimeric diphenyltin chalcogenides (Ph2SnE)3 (E=S (1), Se (2), Te(3)) have been synthesized by reaction of Ph2SnCl2 with Li2E and characterized by multinuclear NMR spectroscopy (1H, 13C, 119Sn, 77Se and 125Te) as well as crystal structure analyses. The three compounds crystallize in the monoclinic space group P21/n and show central six-membered rings Sn3E3 in twisted boat conformations. For 1 density functional theory (DFT) calculations at the B3LYP/6-31G* level of theory have revealed the twisted boat conformation as the global minimum. Additionally a boat conformation (+3.4 kJ mol−1) and a chair conformation (+7.9 kJ mol−1) have been calculated. The mutual repulsion of the phenyl rings in the chair conformation is also evident from the increased bond angles of the Sn3S3 ring in 1.