NLO characterization for novel borinates: evaluation of the N-B bond

Abstract

The following work presents the linear and nonlinear optical (NLO) properties for two ligands (L1-L2) derived from cinnamaldehyde and their corresponding boron complexes (B1-B2). These organic molecules have a backbone with electronic π-systems possessing different "push-pull" features. The structure confirmation of compounds L1 and B1 was made through X-ray diffraction analysis, wherein is observed that planar conformation is conserved after boron complexation on B1. Linear absorption of ligands and boron complexes shows a red shift after boron complexation which could be attributed to more efficient intramolecular charge transfer. Second and third-order NLO responses were performed by Electric Field Induced Second Harmonic (EFISH) Generation technique at 1.9 μm and Third-Harmonic Generation (THG) at 1.9 and 1.067 μm, respectively. Experimental results showed an increment on the hyperpolarizabilities values from ligands to boron complexes which are attributed to N→B coordinative bond. The first hyperpolarizability increased by factors of 3 and 2 from L1 to B1 and L2 to B2, respectively. Individually, these studies demonstrate that B1 is the strongest NLO compound, showed values of first hyperpolarizability 126×10^-24 and second hyperpolarizability 35×10^-24.