Preparation, properties, and structures of bis(O-ethyl dithiocarbonato)-dihalogenotin(IV) and di-µ-thio-bis[bis(O-ethyl dithiocarbonato)tin(IV)]

The complexes [Sn(S₂COEt)₂X₂], X = Cl, Br, or I, have been isolated as stable crystalline compounds. The corresponding complexes [Sn(S₂COEt)₃X] and [Sn(S₂COEt)X₃] could not be isolated, it being postulated that the former rearranges to yield the dimeric compound [(EtOCS₂)₂SnS₂Sn(S₂COEt) ₂]. Structure determinations carried out by single-crystal X-ray diffraction methods of [Sn(S₂COEt)₂Br₂] and [Sn(S₂COEt)₂l₂] show that in both cases the tin atom is six-co-ordinate with the halide atoms cis (Sn-Br, l = 2.54, 2.75 Å). The mutually trans Sn-S distances in each complex are shorter (2.52 Å) than the Sn-S distances trans to the halide [2.59 (bromide), 2.64 Å (iodide)]. For [Sn(S₂COEt)₂Br₂], the cell is monoclinic, space group C2/c, with a = 14.27(1), b = 16.894(8), c = 6.360(5) Å, β = 100.41 (5)°, Z = 4; R was 0.037 for 1 342 'observed' reflections. For [Sn(S₂COEt)₂l₂], the cell is monoclinic, space group P2₁/n, with a = 14.026(6), b = 11.210(4), c = 10.203(4) Å, β = 91.96(3)°; Z = 4, R being 0.030 for 2 512 'observed' reflections.