Binuclear Nickel(II) Complexes Based on Bridging Oxalate and Pseudohalides as Peripheral Ligands: Synthesis, Crystal Structure, DFT Calculations and Magnetic Properties of [{Ni(X)(dien)}2(μ-ox)]·nH2O Complexes (X = N3−, NCS−,n= 0; NCO−,n= 1)

Nickel(II) molecular complexes were obtained by water displacement reactions of [{Ni(dien)(H2O)}2(μ-ox)]Cl2 and the corresponding pseudohalide. The three nickel(II) compounds [{Ni(N3)(dien)}2(μ-ox)] (1), [{Ni(NCO)(dien)}2(μ-ox)] · H2O (2) and [{Ni(NCS)(dien)}2(μ-ox)] (3) are almost isostructural. The structure determinations reveal the presence of a binuclear complex with C2h 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 nitrogen atoms of the diethylenetriamine ligand in a fac arrangement and one nitrogen atom from a pseudohalide ligand. Mag…