engleski

New tetranuclear thiocarboxylate complexes of molybdenum(V)

Molybdenum(V) complexes with sulphur donor ligands are of interest due to their relevance in the redox active molybdoenzymes. The novel tetranuclear complexes have been prepared by the reactions of binuclear oxomolybdenum(V) complexes [Mo_2O_3(acac)_4] (acac = 2,4-pentanedionato) with thiobenzoic (1) and thiotrimethylacetic (2) as well as by reaction of [Mo_2O_3(ba)_4] (ba = 1-phenyl-1,3-butanedionato) with thioacetic acid (3). The molecular structures of the complexes 1, 2 and 3 have been determined by single crystal X-ray crystallography. The centrosymmetrical tetranuclear complexes contain Mo_4O_6S_2 cores bridged through beta-diketonato and thiocarboxylato ligands. Four coordination octahedra are fused together by sharing common edges thus allowing the formation of localized metal - metal bonds between two pairs of molybdenum atoms. The insertion of sulfur atoms into the MoSMo bridges originates from H_2S produced in situ from the molybdenum catalysed hydrolysis of thioacids.

Crystal structures; Oxomolybdenum(V) complexes; Thiocarboxylate complexes; Tetranuclear molybdenum complexes; Thio-ligands

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