Synthesis, spectroscopy and structures of oxalato -Bridged binuclear nickel(II) complexes

Two binuclear nickel( II) complexes of formula {[(tacn)Ni(H2O)](2)(mu - C2O 4)} I-2. 2H(2)O (1) and {[(tacn)Ni(H2O)](2)(mu - C2O4)}(ClO4)(2). 2H(2)O (2 ), where tacn = 1,4,7 - triazacyclononane, have been synthesized. The cryst al structures show that nickel( II) ions are bridged by oxalate and each ni ckel(II) coordinates with three nitrogen atoms of tacn and one water molecu le to form octahedron. The hydrogen bonds were observed between coordinated water and lattice water molecules. The solid reflection spectra and soluti on absorption spectra of 1 and 2 have been measured.