Intriguing Second???Order NLO Switches Based on New DTE Compounds

Two new photochromic compounds bearing a dithienylethene unit have been designed, synthesized, and well characterized. The first contains a platinum dialkynyl moiety whereas the second bears a simple phenyl-dimethylamino fragment. Both compounds have demonstrated an excellent photochromic behavior. This efficient photochromism is the springboard for a significant photomodulation of the second-order nonlinear optical properties, determined in dichloromethane solution by means of the Electric Field Induced Second Harmonic generation technique. The results are of interest for the design of reversible NLO switches as a tool for emerging photonic technologies.