RING SIZE CONTROL IN DIORGANOTIN SULFIDES BY INTRAMOLECULAR SN-N COORDINATION

The synthesis of intramolecularly coordinated organotin sulphides, [(Me2NCH2CH2CH2)2SnS]n (1) and [Me2NCH2CH2CH2Sn(Ph)S]n (2), is described. Compounds 1 and 2 are dimers in chloroform solution (n = 2). Compound 1 forms a centrosymmetric dimer with a planar rectangular Sn2S2 four-membered ring in its centre. The tin atoms show a distorted trans-cis-cis octahedral coordination by 2C, 2N and 2S. The tin-nitrogen distances are 2.810(3) and 3.158(5) angstrom. Compound 1 can be regarded as a model substance for nucleophilic attack at penta-coordinate tin centres. Although the degree of intramolecular coordination of nitrogen to tin is temperature dependent, the four-membered Sn2Sn2 ring remains inert in solution. The existence of the asymmetric tin compound (Me2NCH2CH2CH2)2SnS2SnBut2 (1a) has been characterized in solution.