Abstract

The new hybrid organic-inorganic copper oxovanadium phosphates of composition Cu 4(bipy) 4V 4O 11(PO 4) 2·nH 2O (n ? 5) (1) and Cu 2(bipy) 2V 2P 2O 12 (2) (bipy = 2, 2?-bipyridine) adopting the triclinic symmetry were obtained by soft hydrothermal routes. Both structures present different oxovanadium phosphate anionic units, resulting from the vertex-sharing of PO 4 and VO 4 tetrahedra, which are coordinated to copper diimine cationic groups to form a ID framework. The VPO structures are reminiscent of the known connectivity and geometry of polyphosphate anions. For the two compounds, the magnetic copper(II) centres are square pyramidally coordinated with two nitrogen atoms of the neutral diimine ligand and three oxygen atoms of the oxovanadium phosphate subunit. The CuN 2O 3 pyramids are linked together by oxo-bridges involving PO 4 tetrahedra in Cu 2(bipy) 2V 2P 2O 12 with the closest Cu-Cu distances corresponding to 4.98 Å. Edge-sharing of the copper pyramids in Cu 4(bipy) 4V 4O 11(PO 4) 2·nH 2O results in the binuclear unit {Cu 2O 4N 4}, with Cu-Cu distances of 3.19 Å. Additional links of these dimers by phosphate oxobridges result in the formation of rectangular tetramers Cu 4 with a copper-copper separation of approximately 4.10 Å. Results of thermal analysis and magnetic susceptibility are presented. © The Royal Society of Chemistry 2005.