S. Chou, Der‐Jen Sun, Jung Y. Huang
Sep 30, 1996
Citations
0
Influential Citations
30
Citations
Journal
Tetrahedron Letters
Abstract
A new series of conjugated thiophene compounds 1-4 containing methylsulfonyl and phenylsnlfunyl acccptors have been synthesized wluch possess efficient second-order optical nonlinearities, lugh thermal stability and good transparency for use as nonlinear optical materials. Copyright © 1996 Elsevier Science Ltd The design and synthesis of new donor-acceptor substituted conjugated compounds is presently a major focus of research in organic nonlinear optical (NLO) chromophores? 3 The sulfone group is a good aceeptor substituent which is synthetically flexible and has broad transparency range in the visible spectrum, and benzene-based 7c-conjugated systems containing a solfone group have been reported? Recently, both molecular orbital calculations 5 and experimental studies 3 have revealed that the products of dipole moment and molecular hyperpolarizability 0t13) of thiophene-contalning conjugated moieties are superior to benzene analogues. Based on the above reasons, we have studied previously the second-order nonlinearities of sulfon~substituted thiophene imino dyes? In this communication we report the synthesis, UV-VIS absorption spectrum, thermal stability and second-order nonlinear optical properties of a series of new thiophene-contalning chromophores 1-4 with methylsulfonyl and phenylsulfonyl acceptors. The general methodology for the synthesis of these methylsulfone- and phenylsulfone-substituted thiophene-containing chromophores 1-4 is shown in Scheme 1. Reduction of compounds 5a 6 and 5b 6 with sodium borohydride gave 6a (96%) and 6b (99%) . Treatment of 6a and 6b with thionyl chloride gave the chloro compounds 7a (95%) and 7b (93%). Phosphonates $a (92%) and 8b (92%) were obtained by reacting