Nonlinear optical thin film device from a chiral octopolar phenylacetylene liquid crystal

J Org Chem. 2012 Dec 7;77(23):10891-6. doi: 10.1021/jo302297j. Epub 2012 Nov 13.

Abstract

A set of chiral discotic phenylacetylenes have been synthesized by 3-fold Sonogashira coupling between different ethynylbenzenes and triiodobenzenes. The resultant bulk materials are fully characterized by polarized optical microscopy (POM), differential scanning calorimetry (DSC), and X-ray diffraction. The octopolar nature of the target compounds is studied by UV-vis absorption spectroscopy and hyper-Raleigh scattering in solution. Optimization of the donor-acceptor substitution yields both high hyperpolarizability values and appreciable mesomorphic properties. A simple thin film device for second harmonic generation has been prepared from the nitro-substituted liquid crystalline derivative.