Synthesis and Characterization of Vanadium(V)-Phosphinimide Complexes

Synthetic routes to vanadium(V)-phosphinimide derivatives are addressed. Initial synthetic efforts afforded the known compound formulated as VCl2(NPPh3)3 which was crystallographically determined to be the salt [VCl(NPPh3)3]Cl (1). Reactions of the vanadiumimide precursors VCl3(NAr) (Ar = Ph, C6H3-2,6-iPr2) with R3PNSiMe3 (R = Ph, iPr, tBu) afforded VCl2(NPh)(NPPh3) (4), VCl2(NPh) (NPiPr3) (5), VCl2(NPh)(NPtBu3) (6), VCl2(NC6H3-2,6-iPr2)(NPPh3) (7), VCl2(NC6H3-2,6-iPr2)(NPiPr3) (8), and VCl2(NC6H3-2,6-iPr2) (NPtBu3) (9) in yields ranging from 72% to 84%. Subsequent alkylation or arylation reactions resulted in VMe2(NC6H3-2,6-iPr2)(NPtBu3) (10), VPh2(NPh)(NPtBu3) (11), VPh2(NC6H3-2,6-iPr2)(NPiPr3) (12), and VPh2(NC6H3-2,6-iPr2)(NPtBu3) (13) while substitution reactions with Li[N(SiMe3)2] and Li[SBn] gave VCl(N(SiMe3)2)(NPh)(NPtBu3) (14) and V(SBn)2(NC6H3-2,6-iPr2)(NPtBu3) (15) in yields ranging from 40% to 49% yield. Polarization of the N-P phosphinimide bond and V-N multiple bond character are evidenced by crystallographic data.