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.