Carbon dioxide cleavage across a tungsten-alkylidyne bearing a trianionic pincer-type ligand

Abstract

The cleavage of carbon dioxide by the tungsten alkylidyne [CF₃-ONO]WCC^tBu(THF)₂ (1) {where CF₃-ONO = (MeC₆H₃[C-(CF₃)₂O])₂N³⁻}, is reported. Splitting of CO₂ yields the tungsten oxo ketene complex [CF₃-ONO]W(O){(CH₃)₃CCCO} (6). The proposed pathway occurs through initial cycloaddition of WC and CO bonds to generate a heterometallacyclobutene, which then rearranges to yield WO and CC bonds. Complex 6 was characterized by multinuclear NMR, IR, and single crystal X-ray diffraction.