Paramagnetic chloro-, alkoxo-, or azidovanadium(IV) complexes supported by an [ONNO]-type amine bis(phenolate) ligand

The reactions between V(N-3)(2)(NMe2)(2) or V(OiPr)(4) and the chelating dianionic bis(phenoxy)amine ligand [ONNO]H-2 afford complexes formulated as [V(N-3)(2)(ONNO)] (1) and [V(OiPr)(2){ONNO}] (2). When refluxed in toluene with an excess of Me3SiCl, compound 2 leads to mono- or dichloro derivatives [V(Cl)(OiPr){ONNO}] (3) and [VCl2{ONNO}] (4) depending on the experimental conditions. The crystal structures of complexes 1-4 were solved and show in all cases an [ONNO] ligand that has phenolate groups in a trans configuration, with both amino-nitrogen donor atoms of the ligand coordinated to the octahedral vanadium center. Complexes 1-4 were further characterized by EPR spectroscopy and susceptibility measurement studies typical of d(1)-paramagnetic V-IV species. ((C) Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004).