Synthesis, physical properties and X-ray crystal structure of an oxovanadium(IV) complex of the pendant-arm macrocycle 6,13-dimethyl 1,4,8,11-tetra-azacyclotetradecane-6,13-diamine

Abstract

The pendant-arm macrocyclic hexa-amine 6,13-dimethyl-1,4,8,11-tetra-azacyclotetradecane-6,13-diamine (L²) co-ordinates to the oxovanadium(IV) cation in a quinquedentate manner. The complex [VO(L²)][ClO₄]₂ crystallises in the monoclinic space group C2/c, a= 25.220(4), b= 10.534(2), c= 16.321 (3)Å, β= 94.53(1)°. The vanadium atom is displaced by 0.397 Å above the macrocyclic plane of four nitrogens towards the oxo ligand, with a pendant amine occupying the trans site. Electron paramagnetic resonance and electronic spectra are consistent with the complex being a vanadyl penta-amine in solution as well as in the solid state.