Heterobimetallic M(II)/Ru(II) (M = Ni, Zn) complexes containing coordination and organometallic sites: Synthesis, characterization, luminescence and NLO properties

Some heterobimetallic complexes of the type [Ni(L1–3)(NC5H4CCC6H4CCRu(dppe)2Cl)] (1a–c) and [Zn(L1–3)(NC5H4CCC6H4CCRu(dppe)2Cl)] (2a–c) have been prepared by the reaction of trans-[RuCl(dppe)2(CCC6H4CC-py-3)] (1) with Ni(II) and Zn(II) in presence of Schiff base ligands L1–3 (where L1 = 2-(pyrrole-2-yl-methylidine)aminophenol, L2 = 5-bromo-2-(pyrrole-2-yl-methylidine)aminophenol and L3 = 5-nitro-2-(pyrrole-2-yl-methylidine)aminophenol. All the complexes were characterized on the basis of elemental analyses, IR, UV–Vis, 1H NMR, and 31P NMR spectral studies and compound trans-[RuCl(dppe)2(CCC6H4CC-py-3)] (1) by single crystal X-ray analysis. Quasireversible redox behavior is accounted for all complexes corresponding to Ni(II)/Ni(III) and Ru(II)/Ru(III) for 1a–c and Ru(II)/Ru(III) for 2a–c. All complexes exhibit intra-ligand (π → π∗) fluorescence with high quantum yield in dimethylformamide. The second harmonic generation (SHG) efficiency of the complexes was measured by Kurtz-powder technique indicating that all complexes display the second harmonic generation (SHG) property.