Cyanovinylheteroaromatics for Organic Nonlinear Optics

Abstract
Effects of various substituents including chromophores on the second harmonic generation (SHG) of Cyanovinylheteroaromatics were examined. The molecular polarizability was calculated by the PPP MO method to correlate SHG responsiveness with chemical structures. 3-[(2-cyano-2-ethoxycarbonyl)ethenyl]indole 8b exhibited good SHG efficiency (PE = 25 U). The X-ray analysis of 8b showed that the crystals belong to novel and the most favorable P1 space group.