Thiocyanato and Schiff base coordinated mono/di-nuclear Ni(II) complexes: Syntheses, crystal structures and protein binding

Two Ni(II) complexes, [Ni2(L1)2(SCN)2(dmf)2] (1) and [Ni(L2)(SCN)] (2) [where HL1 = 2-ethoxy-6-[(2-phenylamino-ethylimino)-methyl]-phenol, HL2 = 2-[(2-pyrrolidin-1-yl-ethylimino)-methyl]-phenol, dmf = N,N-dimethylformamide], have been synthesized and characterized by single crystal X-ray diffraction, IR and mass spectroscopic studies. In the centrosymmetric complex 1, two Ni(L1) fragments are connected via µ2-oxo bridges and the metals complete the octahedral coordination with one thiocyanate and one dmf solvent molecule. In complex 2, the Ni(II) ion is coordinated by the tridentate Schiff base and a thiocyanate in a square planar environment. Both the complexes form 1D supra-molecular network through CH…π interactions and complex 2 also via H-bonding. The interaction of complexes with serum albumins was investigated using UV–Vis absorption and fluorescence spectroscopic techniques.