Structural and thermal properties of some neodymium (III) complexes

Some neodymium (III) complexes (1-5) having tp [hydrotris (pyrazol-1-yl) borate], bipy (2,2'-bipyridine) and phen (1,10-phenanthroline) as nitrogen donor ligands have been synthesized. These complexes have been characterized by elemental analysis, IR, thermal, magnetic measurements and X-ray crystallographically. The X-ray studies demonstrated that complexes 1, 2 and 3 crystallize in triclinic space group P (1) over bar with cell dimensions a = 11.745(3), b = 12.566(3), c = 17.654(5) A for 1; a = 11.561(5), b = 12.020(5), c = 12.286(5) A for 2; a = 8.474(3), b = 8.832(3), c = 15.788(5) A for 3. Complexes 4 and 5 crystallize in the monoclinic space group P2(1)/c with cell dimensions a = 18.396(12), b = 10.764(6), c = 13.112(9) A for 4; a = 12.587(4), b = 10.629(3), c = 22.696 (8) A for complex 5. In all these complexes except 1, the coordination number around neodymium center is eight whereas in complex 1, each neodymium is seven coordinated. The IR studies suggested that the benzoate groups in complexes 1 and 2 are coordinated as bidentate bridging whereas in complex 5, the coordination of benzoate groups occur in both bridging as well as in bidentate chelating manner. Thermogravimetric analysis showed that in complexes 3 and 4, the loss of coordinated methanol molecule occurs at 135 degrees C and of coordinated water molecule occurs at 165 degrees C. This is followed by the complete decomposition and the formation of thermally stable neodymium oxide (Nd2O3). (c) 2007 Published by Elsevier B.V.