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

Abstract

The novel tetranuclear complexes of the type [Mo 4O 6S 2(R′COCHCOCH 3) 2(OSCR″) 2], where R′ = –CH 3 or –C 6H 5 and R″ = –C 6H 5, –CH 3, –C(CH 3) 3 or –CH 2CH(CH 3) 2, have been prepared by the reactions of dinuclear oxomolybdenum(V) complexes [Mo 2O 3(acac) 4] (acac = 2,4-pentanedionato) or [Mo 2O 3(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) acid, respectively. The molecular structures of the complexes 1, 3 and 6 have been determined by a single crystal X-ray crystallography. The centrosymmetrical tetranuclear complexes contain Mo 4O 6S 2 cores bridged through β-diketonato and thiocarboxylato ligands. Four coordination octahedra are fused 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.