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Reactions of an (Arylimido)vanadium(V)−Alkylidene, V(CHSiMe3)(N-2,6-Me2C6H3)(NCtBu2)(PMe3), with Nitriles, Diphenylacetylene, and Styrene

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journal contribution
posted on 27.10.2008, 00:00 by Wenjuan Zhang, Junji Yamada, Kotohiro Nomura
Reactions of a vanadium(V)−alkylidene, (ArN)V(CHSiMe3)(NCtBu2)(PMe3) (1, Ar = 2,6-Me2C6H3), with various nitriles, diphenylacetylene, and styrene have been explored. Treatment of 1 with RCN (R = Me, tBu, Ph) afforded a ring-opened bis(imido) complex, (ArN)V[NC(R)CHSiMe3](NCtBu2)(PMe3) [R = Me (2), tBu (3), Ph (4)], and the structure of 4 by X-ray crystallography indicates that 4 has a distorted tetrahedral geometry around vanadium. Insertion of the nitrile into 24 did not occur upon further addition. The reaction of 1 with 1.0 equiv of PhCCPh afforded the corresponding metallacyclobutene analogue, (ArN)V[C(Ph)C(Ph)CHSiMe3)](NCtBu2)(PMe3) (5). The reaction of 1 with styrene afforded the metallacyclopropane analogue, (ArN)V(CH2CHPh)(NCtBu2)(PMe3) (6), although the reaction with 1,1-diphenylethylene did not take place. The X-ray crystallographic analysis of 6 indicates that the vanadium atom in 6 is pentacoordinated with the arylimido ligands in the apical site of a distorted square pyramid.