Modeling the Tungsten Sites of Inactive and Active Forms of Hyperthermophilic Pyrococcus furiosus Aldehyde Ferredoxin Oxidoreductase

Abstract

The complex [Et4N]2[WVIO2(mnt)2] (1), [Et4N]2[WIVO(mnt)2] (2), and [Et4N]2[WVIO(S2)(mnt)2] (3) (mnt2- = 1,2-dicyanoethylenedithiolate) have been synthesized as possible models for the tungsten cofactor of inactive red tungsten protein (RTP) and the active aldehyde ferredoxin oxidoreductase (AOR) of the hyperthermophilic archaeon Pyrococcus furiosus. The [Ph4P]+ salt of the complex anion of 1·2H2O crystallizes in space group Pbcn, with a = 20.526(3) A, b = 15.791(3) A, c = 17.641(3) A, and Z = 4. The WVIO2S4 core of [Ph4P]2[WVIO2(mnt)2]·2H2O has distorted octahedral geometry with cis dioxo groups. 2 crystallizes in space group P21212, with a = 14.78(3) A, b = 30.08(2) A, c = 7.37(4) A, and Z = 4. The complex anion of 2 has a distorted square-pyramidal structure with an axial WO bond. 3 crystallizes in space group P21/a, with a = 12.238(3) A, b = 18.873(2) A, c = 15.026(2) A, β = 102.84(2)°, and Z = 4. The anion of 3 with a terminal oxo group and a dihapto disulfido ligand in an adjacent position is the fir...