Surface organometallic chemistry of vanadium(V): reactivity of (ButN)VNp3 towards silica

The reaction of (ButN)VNp3 towards silica dehydroxylated at 773 K was studied by in situ FT-IR, 13C CP-MAS NMR, 51V MAS NMR, ESR, chemical analysis of the evolved gases and chemical reactivity. Upon heating at 323 K under static vacuum at least four surface organometallic vanadium species are formed. However, after treatment at 373 K under vacuum (SiO)2V(NBut)Np (B) appears to be the major surface species. This species reacts with neopentane, at 423 K, via a C–H addition to the VN bond. Heating of B under hydrogen does not lead to surface vanadium hydride species but, presumably, to hydrogenolysis of SiO–V bonds, elimination of NH2But and formation of ionic surface species, [SiO]−[ButNH3]+.