Synthesis of poly(dithienogermole-2,6-diyl)s

Poly[4,4-di(2-ethylhexyl)dithienogermole-2,6-diyl] was prepared by palladium-catalyzed Stille homocoupling of 6-bromo-2-(trimethylstannyl)-4,4-di(2-ethylhexyl)dithienogermole, while a similar cross-coupling of 2,6-dibromo-4,4-dioctyldithienogermole with 2,6-bis(trimethylstannyl)-4,4-dioctyldithienogermole provided poly(4,4-dioctyldithienogermole-2,6-diyl). These polymers showed broad absorption bands in the UV-vis spectra, which were red-shifted from that reported previously for the silicon analogue poly(dithienosilole-2,6-diyl). Potential applications of the polymers as active materials for bulk heterojunction-type polymer solar cells and thin film transistors were explored.