NLO active CuII/RuII and CdII/RuII coordination-organometallic complexes: synthesis, structural characterization and photoluminescence properties

Abstract

CuII/RuII and CdII/RuII hybrid complexes [Cu(L1–3)(NC5H4C≡CRu(dppe)2Cl)] (1a-3a) and [Cd(L1-3)(NC5H4C≡CRu(dppe)2Cl)] (1b–3b) have been prepared by reaction of trans-[RuCl(dppe)2(C≡C-py-3)] (1) with copper or cadmium acetate in the presence of Schiff base ligands LH1–3 (where LH = 2-(pyrrole-2-yl-methylidine)aminophenol (LH1), 5-bromo-2-(pyrrole-2-yl-methylidine)aminophenol (LH2) and 5-nitro-2-(pyrrole-2-yl-methylidine)aminophenol (LH3)). The hybrid materials were characterized on the basis of elemental analyses, TEM, IR, UV–visible, 1H NMR, and 31P NMR spectral studies. TEM overview observations revealed well-dispersed spherical nanoparticles of ~60 nm are formed. Quasireversible redox behavior is observed for CuII/RuII complexes corresponding to CuI/CuII and RuII/RuIII couples. All the complexes exhibit blue-green emission as a result of fluorescence from the intraligand (π → π*) emission excited state with good quantum yield. The second-order nonlinear optical (NLO) properties of CuII/RuII and CdII/RuII complexes have been investigated by the Kurtz-powder method. The second harmonic generation efficiency of these complexes show that these complexes are NLO active and display good second-order nonlinear optical activity.