Synthesis and structural characterizations of new mononuclear and dinuclear molybdenum(V) anions containing trithiocarbonate ligands

This paper describes the syntheses and structures of two new Mo(V) compound s obtained via the reductive addition of CS2 on the high-valent tetrathiome talate MoS42-. The mononuclear compound (NEt4)(3)[Mo(eta(2)-CS3)(4)], 1, wa s selectively produced by reaction of (NEt4)(2)[MoS4] with excess of CS2 in a mixture of CH3OH and NH3 in the presence of H2S. Compound 1 crystallizes in the monoclinic system, space group P2(1)/n, a = 18.5249(5) Angstrom, b = 11.8058(4) Angstrom, c = 20.2942(5) Angstrom, beta = 102.951(1)degrees, Z = 4. In total, 11 176 reflections with I > 2 sigma(I) were employed, and t he structure solution was refined to R = 0.0496. Compound 1 was revealed to be a mononuclear paramagnetic species containing only eta(2)-CS3 ligands. The geometry at the Mo(V) center is described as a regular dodecahedron. Co mpound 1 represents a unique example of a stable mononuclear Mo(V) complex containing trithiocarbonate ligands. The reaction of [MoS4](2-) With CS2 wi thout H2S gives (NBu4)(2)[Mo-2(eta(2)-CS3)(4)(mu-(S-2)(2)], 2, obtained as a powder which was recrystallized at 4 degrees C. Compound 2 crystallizes i n the monoclinic system, space group P2(1)/n, a = 8.7930(1) Angstrom, b = 2 2.3059(3) Angstrom, c = 14.5029(2) Angstrom, beta = 98.445(1)degrees, Z = 4 . In total, 8323 reflections with I > 2 sigma(I) were used, and the structu re solution was refined to conventional R = 0.0425. Compound 2 is a dinucle ar species containing eta(2)-CS3 ligands, the two Mo(V) being linked throug h two disulfido bridging groups. The Mo-Mo distance in 2 is 2.8128(6) Angst rom, a value in very good agreement with those observed for dinuclear Mo(V) species.