Novel pyrazolate-bridged binuclear Ni(II), Cu(II) and Zn(II) complexes: Synthesis, X-ray crystal structure and nonlinear optical studies

In this paper, a pyrazole based ligand (1) containing nitrogen and sulfur donors was prepared and used in the synthesis of the following new binuclear Ni(II), Cu(II), and Zn(II) complexes [Ni-2(EtNCSPz(Me2))(2)(mu-Pz(Me2))(2)] (2), [Cu-2(EtNCSPz(Me2))(2)(mu-Pz(Me2))(2)] (3) and [Zn-2(EtNCSPz(Me2))(2)(mu-Rz(Me2))(2)] (4). The ligand and complexes were characterized by spectroscopic and physico-chemical methods. The crystal structure of [Ni-2(EtNCSPz(Me2))(2)(mu-Pz(Me2))(2)] was determined by X-ray diffraction analysis. Crystal structure of the (2) describes a binuclear complex, in which nickel ions are bonded by N3S donor atoms set in distorted square planar coordination geometry and the dimethyl pyrazolate groups are placed as the bridge among the metal centers. The nonlinear optical responses of the prepared ligand and metal complexes were investigated under irradiation of 35 mW continuous wave He-Ne (632.8 nm) laser. The z-scan technique was applied for measurement the second-order refractive index (n(2)) of the synthesized samples. Results show that copper complex (3), demonstrates the highest value of the measured n(2) ( - 10.18 x 10(-7) mmW(-1)).