Reduction of Bis(dithiolene)oxo(disulfido)tungsten(VI) Complex with Dihydrogen Related to the Chemical Function of the Fourth Tungsten-Containing Enzyme (WOR4) from Pyrococcus furiosus

Sulfurization of five-coordinate [WIVO(1,2-benzenedithiolate)2]2− proceeds under very mild conditions to form seven-coordinate [WVIO(η2-S2)(1,2-benzenedithiolate)2]2−, from which H2S was generated by treatment with H2. This is the first functional model for the fourth tungsten-containing WOR4 enzyme. Kinetics and isotope-scrambling experiments have suggested the existence of six-coordinate WV(η1-S2) species as a key reaction intermediate.