Reactivity studies of a pseudo three-coordinate vanadium(II) complex: Synthesis of terminal oxo and sulfido complexes of vanadium(IV) and S–S and Se–Se reductive bond cleavage reactions

Terminal oxo and sulfido complexes in the form of (nacnac)VE(Ntol2) (nacnac = [ArNC(CH3)]2CH−, Ar = 2,6-(CHMe2)2C6H3, Ntol2 = −N(C6H4-4-Me), E = O (1), S (2)) were isolated from treatment of the masked three-coordinate vanadium(II) complex, (nacnac)V(Ntol2), with C5H5NO and S8, respectively. Both vanadium(IV) species, 1 and 2, have been characterized by room temperature X-band EPR spectroscopic studies, and in the case of complex 1, a single crystal molecular structure confirmed the presence of a terminal oxo moiety. Moreover, reaction of (nacnac)V(Ntol2) with diphenyl–disulfide and diphenyl–diselenide results in the reductive cleavage of these compounds to produce the vanadium(III) complexes (nacnac)V(XPh)(Ntol2) (X = S, (3), Se (4)). A molecular structure of the phenylsulfide complex, 3, confirmed formation of the d2 complex resulting from reductive cleavage of the S–S bond.

Graphical abstractUsing a masked three-coordinate complex, (nacnac)V(Ntol2) (nacnac = [ArNC(CH3)]2CH−, Ar = 2,6-(CHMe2)2C6H3, Ntol2 = −N(C6H4-4-Me) we describe a facile approach to preparing terminal vanadium(IV) oxo and sulfido complexes (nacnac)VE(Ntol2) (E = O or S) by taking advantage of the vanadium(II)/(IV) redox couple. Likewise, we report one-electron chemistry of (nacnac)V(Ntol2) with PhEEPh (E = S or Se) to form the vanadium(III) complexes (nacnac)V(EPh)(Ntol2).Figure optionsDownload full-size imageDownload as PowerPoint slideResearch highlights► A pseudo three-coordinate vanadium(II) complex provides easy access to terminal oxo and sulfido vanadium(IV) complexes. ► These terminal chacogenides have one unpaired d-electron. ► Facile reduction of S–S and Se–Se bonds allows for entry to V(III) complexes.