Structural Characterization of a Fluorido-Amide of Niobium, and Facile CO2 Incorporation Affording a Fluorido-Carbamate

We have prepared the first niobium(V) compounds bearing fluorido and monodentate amido ligands (1a–c), which are tetranuclear cations, by the reaction between NbF5 and Me3SiNMe2 in the presence of a chloride (or bromide) source. The fluorido/carbamato derivative NbF2(O2CNMe2)3 (2) was obtained in good yield from the reaction of NbF5 and Me3SiNMe2 in the presence of carbon dioxide at 1 atm pressure and ambient temperature. All the products were characterized by analytical and spectroscopic (IR, multinuclear NMR) methods, and by X-ray diffraction in the cases of 1b,c. DFT calculations were useful for elucidating the structures of the products and also for providing an insight into the reaction pathways.