Synthesis of novel rod-shaped and star-shaped fluorescent phosphane oxides -: Nonlinear optical properties and photophysical properties

The design of a new class of fluorophores is presented. Some push-pull chromophores (D-pi-A) containing polyphenylethynyl units and a phosphane oxide moiety were efficiently prepared from common intermediates. Straightforward syntheses gave novel one-armed, rod-shaped and three-armed, star-shaped fluorophores. The optical properties of the resulting star-shaped derivatives were evaluated, showed high fluorescence quantum yields, and their excitation induces very efficient charge redistribution. More-over, thanks to their push-pull character, the molecules exhibited significant second-order NLO properties with good transparency, up to 67 center dot 10(-30) esu at 1907 nm, with an absorption lambda(max) at 369 nm. The effect of the donor group and of the number of phenylethynyl arms have been studied in this work.