Second-Order Nonlinear Optical Properties of Push−Pull Bis(phenylethynyl)benzenes and Unsymmetric Platinum Bis(phenylacetylide) Complexes

A series of unsymmetric π-donor−acceptor (D/A) bis(phenylethynyl)benzenes was prepared in a two-step sequence via Pd/Cu catalyzed cross-coupling reactions of 1,4-diiodobenzene and the corresponding 4-p-R-phenylethynes. Related unsymmetric D/A platinum trans-bis(acetylide) complexes were also prepared in a stepwise fashion. An investigation of their linear and nonlinear optical properties reveals excellent tradeoff in terms of nonlinearity versus transparency for these classes of chromophores.