Structure-property relationships of acylated asymmetric dithienophospholes

Friedel-Crafts acylation was found to be an effective way to selectively access monofunctionalized dithienophospholes. Absorption and emission properties of the acylated compounds exhibited high extinction coefficients, relative to unsubstituted dithienophosphole and bathochromic shifts when in the presence of Lewis-acids, e.g., AlCl(3) and BF(3), effectively demonstrating that the emissive characteristics could be tuned. Subsequent treatment of the asymmetric mono-substituted compounds with N-bromosuccinimide, yielded materials that were later employed in Ni-catalyzed Yamamoto cross-coupling reactions. The resulting cross-coupled material exhibited a substantial increase in its extinction coefficient as well as a further red-shifted absorbance and emission profile, relative to the mono-functionalized phosphole. (C) 2010 Academie des sciences. Published by Elsevier Masson SAS. All rights reserved.