A pentanuclear oxovanadium(V) phosphate complex with phenanthroline

A novel crystalline organic–inorganic hybrid oxovanadium(V) phosphate complex, {[V2O4(Phen)2(PO4)]2VO(OH)}3/4 {[V2O4(Phen)2(HPO4)]2}1/4 · 4.5H2O (where Phen = 1,10-phenanthroline), was isolated using the hydrothermal synthetic approach, and characterised structurally using thermal (TG and DSC) and CHN elemental analysis, vibrational spectroscopy (IR and Raman), single crystal X-ray diffraction and solid-state NMR. The structure contains two similar binuclear dioxovanadium(V) moieties, with all V5+ centres in a highly distorted octahedral coordination geometry. These are further bridged via a fifth V5+ centre, in a highly distorted tetrahedral coordination geometry, leading to the formation of a pentanuclear moiety. Individual complexes close-pack in the solid-state via offset π–π (between neighbouring phenanthroline residues) and hydrogen bonding interactions (with the water molecules of crystallisation). 51V and 31P solid-state NMR proved unequivocally the presence of these two coordination environments for the V5+ centres.