Synthesis and characterization of a series of new thiocarboxylate complexes of molybdenum(V)

The novel tetranuclear complexes of the type [Mo4O6S2(R'COCHCOCH3)(2)(OSCR ")(2)], where R' = -CH3 or -C6H5 and R " = -C6H5, -CH3, -C(CH3)(3) or -CH2C H(CH3)(2), have been prepared by the reactions of dinuclear oxomolybdenum(V ) complexes [Mo2O3(acac)(4)] (acac = 2,4-pentanedionato) or [Mo2O3(ba)(4)] (ba = 1-phenyl-1,3-butanedionato) with thiobenzoic (1 and 5), thioacetic (2 and 6), thiotrimethylacetic (3 and 7) and thio-3-methylbutyric (4 and 8) a cid, respectively. The molecular structures of the complexes 1, 3 and 6 hav e been determined by a single crystal X-ray crystallography. The centrosymm etrical tetranuclear complexes contain Mo4O6S2 cores bridged through beta-d iketonato and thiocarboxylato ligands. Four coordination octahedra are fuse d by sharing common edges thus allowing the formation of localized metal-me tal bonds between two pairs of molybdenum atoms. The insertion of sulfur at oms into the MoSMo bridges originates from H2S produced in situ from the mo lybdenum catalysed hydrolysis of thioacids. (C) 1999 Elsevier Science S.A. All rights reserved.