Surface organometallic chemistry of vanadium(V): reactivity of (Bu(t)N=)VNp3 towards silica

The reaction of (Bu 'N=)VNp3 towards silica dehydroxylated at 773 K was stu died by in situ FT-IR, C-13 CP-MAS NMR, V-51 MAS NMR, ESR, chemical analysi s of the evolved gases and chemical reactivity. Upon heating at 323 K under static vacuum at least four surface organometallic vanadium species are fo rmed. However, after treatment at 373 K under vacuum (drop SiO)(2)V(=NBu ' )Np (B) appears to be the major surface species. This species reacts with n eopentane, 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 drop SiO-V bonds, elimination of NH2Bu ' and formati on of ionic surface species, [drop SiO]-[Bu ' NH3](+). (C) 2001 Elsevier Sc ience B.V. All rights reserved.