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(SCH2CH2- 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 (Ob)2Mo(Ot)(SPh)2 coordination spheres (b, bridging; t, terminal) share an Ob--Ob edge with cis-bent stereochemistry. Important average dimensions are Mo-Mo 2.61, Mo-S 2.45, Mo-Ot 1.68, Mo-Ob 1.94 Ǻ, Mo 0.71 Ǻ above the (Ob)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.