Synthesis, structure, and second-order nonlinear optical properties of copper(II) and palladium(II) acentric complexes with N-salicylidene-N'-aroylhydrazine tridentate ligands.

Two new N-salicylidene-N'-aroylhydrazines ligands have been prepared: N-4-diethylaminosalicylidene-N'-4-nitrobenzoyl-hydrazine (L(1)) and N-4-diethylaminosalicylidene-N'-4-(4-nitrophenylethylidene)-benzoyl-hydrazine (L(2)). 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 L(1) and L(2) 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 mubeta values up to 1500 x 10(-48) esu for an incident wavelength of 1.907 microm.