POLY(ALKYL THIOPHENE-3-CARBOXYLATES) - SYNTHESIS AND CHARACTERIZATIONOF POLYTHIOPHENES WITH A CARBONYL GROUP DIRECTLY ATTACHED TO THE RING

Polythiophenes with electron-withdrawing ester groups attached at the 3-position, namely poly(hexyl thiophene-3-carboxylate) (1a) and poly(o ctyl thiophene-3-carboxylate) (1b), have been synthesized using the Ul lmann reaction with copper powder in DMF. Characterization of the poly mers includes IR, H-1 and C-13 NMR, and UV-vis spectroscopy as well as TGA and molecular weight studies. The polymers also show red-orange a nd red fluorescence, respectively. The same polymers prepared using Ni (0) instead of Cu gave polymer with comparable molecular weights but h igher polydispersity, which was not as uniform as shown by NMR spectro scopy and which had shorter conjugation lengths, as shown by blue-shif ted UV-vis absorption and fluorescence maxima.