SYNTHESIS, MOLECULAR-STRUCTURE, AND PHYSICAL-PROPERTIES OF AN OXOMOLYBDENUM(IV) COMPLEX WITH P-CHLOROBENZENETHIOLATE, [MO(IV)O(P-CLC6H4S)4]2-, AS A MODEL OF ACTIVE-SITES OF REDUCED MOLYBDO-OXIDASES

A monomeric oxomolybdenum(IV) complex with p-chlorobenzenethiolate, (NEt4)2[MoIVO(p-ClC6H4S)4] (1a), was synthesized as a relevant model of active sites of reduced molybdo-oxidases by reduction of (NEt4)[MOVO(p-ClC6H4S)4] (2) with NEt4BH4. This complex was characterized by absorption, Raman, and H-1 NMR spectra and cyclic voltammograms, and compared with 2. The complex (PPh4)2[MoIVO(p-CIC6H4S)4] (1b), which was prepared by the cation exchange reaction of la, crystallizes in the triclinic, space group P1BAR with a=21.131(18), b=13.690(3), c=13.490(5) angstrom, alpha=100.96(3)-degrees, beta=117.62(3)-degrees, gamma=78.77(5)-degrees, and Z=2. The average distances of Mo-S and Mo-O bonds of this complex are 2.415 and 1.690(9) angstrom respectively. The O-Mo-S-C torsion angles (theta) in lb range from 74-degrees to 91-degrees. EHMO calculation on [MoIVO(SH)4]2- showed that this conformation is thermally stable.