The formation and molecular structure of the Di-μ-oxo-di[di(benzenethiolato)-oxomolybdate(v)] dianion

Abstract

The orange-red complexes (R₄N)₂ [Mo₂O₄(SPh)₄] (R = Me, Et), (Et₄N)₂ [Mo₂O₄(SCH₂CH_2- CH₂S)₂] and (Et₄N)₂ [Mo₂O₄{SCH₂(CHOH)₂CH₂S}₂] have been synthesized. Crystalline (Me₄N)₂ [Mo₂O₄(SPh)₄], space group P1, contains two [(μ-O)₂(OMo(SPh)₂)₂]^2- complexes in each of which two approximately square-pyramidal (O_b)₂Mo(O_t)(SPh)₂ coordination spheres (b, bridging; t, terminal) share an O_b--O_b edge with cis-bent stereochemistry. Important average dimensions are Mo-Mo 2.61, Mo-S 2.45, Mo-O_t 1.68, Mo-O_b 1.94 Ǻ, Mo 0.71 Ǻ above the (O_b)₂S₂ basal plane. There occur two different orientations of S-C vectors, relative to the Mo-Mo vector, associated with two clearly distinct classes of S-Mo-S angles, 81.9±0.5 and 73.8±0.4°. The latter abnormally small angle, concomitant with an interligand S--S distance of 2.94 Ǻ, occurs only in the conformation where S--S σ-orbital overlap is possible, and suggests the existence of some interligand bonding. Crystal data: a 12.376, b 14.513, c 11.307 Ǻ, α 104.00, β 99.55, γ 71.32°, cell contents 2xMo₂S₄O₄N₂C₃₂H₄₄, 3207 reflections, R 0.033.