New hypercoordinated diorganotin(IV) compounds with dithiocarbamato ligands. Synthesis and structural characterization

Abstract

Several homo- and heteroleptic diorganotin(IV) dithiocarbamato halides of type RR'Sn(S2CNR″2)Cl [R = R' = Me, R'' = Me (1), Et (2); R = R' = nBu, R'' = Me (3), Et (4); R = 2-(Me2NCH2)C6H4, R' = Me, R'' = Me (5), Et (6)] and pseudo-halides of type RR'Sn(S2CNR″2)(NCS) [R = R' = Me, R'' = Me (7), Et (8); R = R' = nBu, R'' = Me (9), Et (10); R = 2-(Me2NCH2)C6H4, R' = Me, R'' = Me (11), Et (12); R' = nBu, R'' = Et (13), R' = 2-(Me2NCH2)C6H4, R'' = Me (14), Et (15)] were prepared by salt metathesis reactions, starting from either RR'SnCl2 or RR'Sn(NCS)2. In all compounds the dithiocarbamato ligand acts as a bidentate moiety. For the compounds 11–15, as well as for the species 5 and 6, of type RR'Sn(S2CNR″2)Cl, bearing aromatic groups with pendant arms attached to tin, the NMR spectra gave no clear evidence for a N→Sn coordination in solution at room temperature. The molecular structures determined by single-crystal X-ray diffraction for compounds 12 and 14, with one or two 2-(Me2NCH2)C6H4 groups, respectively, revealed the existence of intramolecular N→Sn interactions in solid state. The IR spectra suggest an isothiocyanato behavior of the NCS group in solid state in all cases, while the 119Sn NMR spectra gave no clear evidence for such a behavior in solution, as no 14N-119Sn couplings were observed. The single-crystal X-ray diffraction studies revealed molecular species for 7, 8 and 12, while 14 is a ionic compound with [{2-(Me2NCH2)C6H4}2Sn(S2CNMe2)]+ cations and SCN− anions.