Structural Aspects of V2( µ;-S2)2(S2CNR2)4 Complexes: the X-Ray Crystal Structure of V2( µ;-S2)2(S2CNEt2)4.2CHBr3

Abstract

Brown V2(p-S2)2(S2CNEt2)4 is produced upon reaction of [vs4]3- with (Et2NCS2)2, in a synthesis similar to that described for V2( �-S2)2(S2CNBui2)4 ( Halbert , T. R., Hutchings, L. L., Rhodes, R., and Stiefel , E. I., J. Am. Chem. Soc., 1986, 108, 6437). Crystals of V2( �;-S2)2(S2CNEt2)4.2CHBr3 are orthorhombic and belong to space group Pbca , with a 10.909(2), b 20.492(2), c 20.471(2) � , V 4576.2 �3, and Z 4 dimers . The structure was solved by Patterson and Fourier methods and refined by using 1189 reflections to final R 0.061 ( Rw 0.059). The vanadium(IV) atoms in the dimeric complex are bridged by two �-k2S,S′: k2S,S′-S22- ligands [S(1)-S(2) 2.00(1) �] and a metal-metal single bond [V-V 2.900(6) �]. Each vanadium atom is further coordinated by two bidentate dithiocarbamate ligands whose arrangement defines a meso isomer with Λ and Δ configurations at the vanadium centres. This Λ Δ diastereomer differs from the Λ Λ -ΔΔ racemate structurally characterized in the case of V2(�-S2)2(S2CNBui2)4 but is the same as that found for the molybdenum(v) dication in [Mo2( �S2)2(S2CNEt2)4] (BF4)2.2CHBr3 ( Kocaba, T., Young, C. G., and Tiekink , E. R. T., Inorg. Chim. Acta, 1990, 174, 143).