Structural characterization and unusual reactivity of oxosulfido-Mo(V) compounds: Implications for the structure and electronic description of the very rapid form of xanthine oxidase

Abstract

The first structural characterization of a mononuclear, EPR-active, oxosulfido-Mo(V) compound related to the very rapid form of xanthine oxidase (VR-XnO) is reported. The compound, [CoCp2][TpiPrMo VOS(2-OC6H4CO2Et)] [Cp = cyclopentadienyl; TpiPr = hydrotris(3-isopropylpyrazol-1-yl)borate], exhibits a distorted octahedral geometry with Mo=O and Mo=S distances of 1.761(5) and 2.215(2) Å, respectively, and an O=Mo=S angle of 107.33(14). Significantly, the MoV=S distance is much shorter than the value of 2.36 Å reported for oxosulfido-Mo(V) compounds (Singh, R.; et al. Inorg. Chem. 1989, 28, 8) but close to the range established for VR-XnO by protein crystallography. The methyl and phenyl esters..