Niobium Bis-alkylidene Complexes Prepared by a Multi-Electron Redox Process

High-valent niobium bis-alkylidene complexes have been structurally authenticated along with the first paramagnetic Nb(IV) alkylidene. The bis-alkylidene complexes presented in this work are thought to be generated via a redox process involving α-hydride elimination from a transient Nb(III) bis-alkyl complex. X-ray diffraction, DFT, and multinuclear NMR studies are consistent with these bis-alkylidenes having drastically different chemical environments.