A NEW PERSPECTIVE OF VANADYL-TARTRATE DIMERS - SYNTHESIS, CRYSTAL-STRUCTURE, SPECTROSCOPIC AND MAGNETIC-PROPERTIES OF THE CHAIN COMPOUND - ([BAVO(C4H2O6)(H2O)(4)](2))(N)

Compound [BaVO(C4H2O6)(H2O)(4)] (C4H2O6 = tartrate ligand) has been synthesized and its crystal structure determined by X-ray diffraction. The compound consists of a chain structure of vanadyl-tartrate dimers and barium cations. These cations are also bound to the tartrate ligands, giving the molecular formula {[BaVO(C4H2O6)(H2O)(4)](2)}(n). The vanadium atom has a penta-coordinated [VO5] environment, while the barium atom has a nona-coordinated [BaO9] environment. Analysis of the susceptibility data yield a practically paramagnetic behaviour for this complex down to 5 F;, with a very slight increase in the chi(m) T value between 5 and 2 K. The ESR spectrum shows a half-field signal characteristic of interactions between two vanadyl centres. The vanadyl dimer has shown weakly coupled exchange to give a low-lying triplet state, as can also be observed by ESR spectroscopy; the different interaction pathways have been analysed.