Binuclear nickel(II) complexes based on bridging oxalate and pseudohalidesas peripheral ligands: Synthesis, crystal structure, DFT calculations and magnetic properties of [{Ni(X)(dien)}(2)(mu-ox)]center dot nH(2)O complexes(X = N-3(-), NCS-, n=0; NCO-, n=1)

Nickel(II) molecular complexes were obtained by water displacement reaction s of [{Ni(dien)(2)(H2O))(2)(mu -ox)]Cl-2 and the corresponding pseudohalide . The three nickel(II) compounds [{Ni(N-3)(dien)}2(mu -ox)] (1), [{Ni(NCO)( dien)}(2)(mu -ox)].H2O (2) and [{Ni(NCS)(dien)}(2)(mu -ox)] (3) are almost isostructural. The structure determinations reveal the presence of a binucl ear complex with C-2h symmetry, where the oxalate ligand is coordinated in a bis(bidentate) fashion to the twofold related nickel atoms. The distorted octahedral environment of each nickel atom is completed by the three nitro gen atoms of the diethylenetriamine ligand in a fac arrangement and one nit rogen atom from a pseudohalide Ligand. Magnetic susceptibility data in the temperature range 4.2-300 K shows intramolecular antiferromagnetic coupling .