A pentanuclear oxovanadium(V) phosphate complex with phenanthroline

• Published in: Inorganic chemistry communications 2006, Vol.9 (1), p.34-38
• Main Authors: Mafra, Luís, Almeida Paz, Filipe A., Shi, Fa-Nian, Fernandez, Christian, Trindade, Tito, Klinowski, Jacek, Rocha, João
• Format: Article
• Language: English
• Subjects: 31P; 51V; Chemical Sciences; Crystal structure; Hydrothermal synthesis; Organic–inorganic hybrid; Oxovanadium phosphate; Solid-state NMR
• ISSN: 1387-7003; 1879-0259
• DOI: 10.1016/j.inoche.2005.09.036

A novel crystalline organic–inorganic hybrid oxovanadium(V) phosphate complex, {[V 2O 4(Phen) 2(PO 4)] 2VO(OH)} 3/4 {[V 2O 4(Phen) 2(HPO 4)] 2} 1/4 · 4.5H 2O (where Phen = 1,10-phenanthroline), was isolated and characterised structurally using several techniques, among which 51V and 31P solid-state NMR studies proved unequivocally the presence of two coordination environments for the V 5+ centres. A novel crystalline organic–inorganic hybrid oxovanadium(V) phosphate complex, {[V 2O 4(Phen) 2(PO 4)] 2VO(OH)} 3/4 {[V 2O 4(Phen) 2(HPO 4)] 2} 1/4 · 4.5H 2O (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 V 5+ centres in a highly distorted octahedral coordination geometry. These are further bridged via a fifth V 5+ 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 V 5+ centres.