N -Heterocyclic carbene and cyclic (alkyl)(amino)carbene complexes of vanadium(III) and vanadium(V).

[VCl 3 (THF) 3 ] offers a convenient entrance point into the chemistry of carbene stabilized V(III) complexes. Herein we report the paramagnetic mono- and biscarbene complexes [VCl 3 (cAAC Me )] 1, [VCl 3 (cAAC Me )(THF)] 1(thf), [VCl 3 (IMes)] 2, [{VCl 2 (IiPr Me )(μ-Cl)} 2 ] 3, [VCl 3 (IDipp)] 4, [VCl 3 (SIDipp)] 5, [VCl 3 (SIDipp)(THF)] 5(thf), [VCl 3 (I t Bu)] 6, [VCl 3 (cAAC Me ) 2 ] 7 and [VCl 3 (IiPr Me ) 2 ] 8. Reaction of 1 with MesMgCl, MesLi and LiNPh 2 afforded the complexes [VCl 2 (Mes)(cAAC Me )] 9, [cAAC Me H] + [VCl 2 Mes 2 ] - 10 and [VCl 2 (NPh 2 )(cAAC Me )] 11. The V(V) complexes [V(O)Cl 3 (IDipp)] 12 and [V(O)Cl 3 (SIDipp)] 13 were selectively prepared from oxygen oxidation of 4 and 5. [V(O)Cl 3 (IDipp)] 12 and [V(O)Cl 3 (IMes)] react with isocyanates to yield the NHC-ligated imido complexes [V(N- p -CH 3 C 6 H 4 )Cl 3 (IDipp)] 14, [V(N- p -FC 6 H 4 )Cl 3 (IDipp)] 15, [V(N- p -CH 3 C 6 H 4 )Cl 3 (SIDipp)] 16, [V(N- p -FC 6 H 4 )Cl 3 (SIDipp)] 17, [V(N- p -CH 3 C 6 H 4 )Cl 3 (IMes)] 18 and [V(N- p -FC 6 H 4 )Cl 3 (IMes)] 19.