Nickel‐Molybdenum and Nickel‐Tungsten Dithiolates: Hybrid Models for Hydrogenases and Hydrodesulfurization

The heterobimetallic complexes [(dppe)Ni(pdt)Mo(CO)4], [(dcpe)Ni(pdt)Mo(CO)4], [(dppe)Ni(pdt)W(CO)4] and [(dcpe)Ni(pdt)W(CO)4] {dppe = Ph2P(CH2)2PPh2; dcpe = Cy2P(CH2)2PCy2; pdt2– = –S(CH2)3S–} have been prepared and structurally characterized. The internuclear separation in these NiIIM0 species is highly sensitive to diphosphine basicity and is smallest in the dppe complexes wherein the planar Ni centres are electron‐poor and require interaction with the group 6 metal. The NiIIW0 species [(dppe)Ni(pdt)W(CO)4] was converted into its stable conjugate acid [(dppe)Ni(pdt)HW(CO)4]+, a rare example of a nickel–tungsten hydride. This NiIIHWII complex is an electrocatalyst for H+ reduction and is relevant to both biological and synthetic H2‐processing catalysts.