N,N-Dialkylcarbamato derivatives of niobium and tantalum as precursors to metal-functionalized silica surfaces

Chemical implantation of Group 5 cations [Nb(III), Nb(V), and Ta(V)] has been carried out under mild conditions by the reaction of N,N-dialkylcarbamato derivatives M(O2CNR2)n (M = Nb, Ta) with silanol groups of amorphous silica, carbon dioxide, and secondary amine being released in the process. The amount of supported cations depends on the metal and on the initial number of N,N-dialkylcarbamato ligands on M; partial reduction to the +4 oxidation state occurs in the case of Nb(O2CNR2)5.