Molybdenum complexes persulfides

A crystal structure determination of [pyH]4[Mo203(S04)(NCS)6] has shown the two molybdenum atoms to be bridged by one oxo and the sulfato ligand. The terminal oxygens are syn and each molybdenum has a distorted octahedral geometry.415 Persulfide bridges have been identified in several dimeric Mov complexes. In each molybdenum is... 

Different members of the xanthine oxidase family show differing susceptibility to cyanide. Thus, while mammalian aldehyde oxidases react more readily with cyanide, purine hydroxylase II imm Aspergillus nidulans was found to be highly resistant and only with extensive treatment did the desulfo form develop. Early XAS work indicated the presence of an oxo-sulfido active site with both Mo=0 and Mo=S coordination, and that the cyanolyzable sulfur is the Mo=S, and resolving a debate in which Mo=S and persulfide were candidates for the cyanolyzable sulfur. Xanthine oxidase also reacts with arsenite As(OH)3 to form an inhibited complex in which molybdenum is bound by arsenic through the labile sulfur (Mo-S-As). The conclusions of the early XAS study have recently been confirmed and extended by protein crystallography of the inhibitory species. ... 

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