Synthesis, Structure, and Second-Order Nonlinear Optical Properties of Copper(II) and Palladium(II) Acentric Complexes with <i>N</i>-Salicylidene-<i>N</i> ‘-aroylhydrazine Tridentate Ligands

Abstract

Two new N-salicylidene-N ‘-aroylhydrazines ligands have been prepared: N-4-diethylaminosalicylidene-N ‘-4-nitrobenzoyl-hydrazine (L1) and N-4-diethylaminosalicylidene-N ‘-4-(4-nitrophenylethylidene)-benzoyl-hydrazine (L2). The ligands are properly functionalized with strong electron donor−acceptor groups and are of potential interest in second-order nonlinear optics (NLO). Dimeric copper(II) and palladium(II) complexes with L1 and L2 have been prepared, and, starting from these, mononuclear acentric adducts with pyridine as a further ligand have been prepared and characterized. The X-ray structures of three adducts are also reported. The NLO activity of the adducts has been determined by EFISH measurements giving μβ values up to 1500 × 10-48 esu for an incident wavelength of 1.907 μm.