Azo-Based Ligands and Metal Complexes for NLO Applications

We present herein the synthesis and the characterization of a bis iminopyridyl ligand that’s functionalized by two azobenzene unit and formulated as 4,4’-((1E,1’E)-(((1E,1’E)-(pyridine-2,6-diylbis(methanylylidene))bis (azanylylidene))bis(4,1-phenylene))bis(-diazene-2,1-diyl))bis(N,N-dimethylaniline) (L1). This ligand reacts with one equivalent of zinc chloride (ZnCl2) to afford the corresponding mononuclear Zn(II) metal complex formulated as [ZnL 3 Cl 2 ]. Single crystals of this complex have been obtained and the X ray crystal structure analysis indicate complex [ZnL 3 Cl 2 ], the tridentate ligand L1 is coordinated to the zinc(II) through its three nitrogen atoms. UV-Visible absorption spectroscopy shows the occurrence of intramolecular charge transfer (ICT) from the electron donating dimethylamino group to the iminopyridyl fragment and that this ICT band is red shifted in [ZnL 1 Cl 2 ] complex due to the Lewis acidity of the zinc(II) metal cation. This results indicate that the resulting [ZnL 1 Cl 2 ] complex is a valuable candidate for Nonlinear Optical (NLO) applications