Computational investigation on the switching efficiency of diarylethene: Comparison between the first hyperpolarizability and exchange interaction

We have calculated the exchange interaction J and the first hyperpolarizability beta for photochromic diarylethenes (DAEs), 5,5'-diphenyl-di(3-thienyl)ethene 1, 5,5'-diphenyl-di(2-thienyl)ethene 2, 2,5-diphenyl-di(3-thienyl)ethene 3, and their corresponding oxidized derivatives. The switching direction of DAE 2 is found to be opposite from DAE 1. The switching direction of DAE 3 is opposite from DAE 1 for J, but not for beta. For all molecules, the switching efficiency (SE) values of beta are smaller than those of J. Oxidizing the sulfur atoms yields rather small variations on SEs of J and beta. The non-trivial structure property relationships for J and beta are rationalized. (C) 2016 Elsevier B.V. All rights reserved