Polythiophenes with vinylene linked ortho, meta and para-carborane sidechains

Jonathan Marshall,Jake Hooton,Adam Creamer,Yoann Porte,Martin Heeney,Peter Beavis,Thomas D Anthopoulos,Raja Shahid Ashraf,Paul N Stavrinou,Hugo Bronstein,Yang Han,Martyn A Mclachlan

doi:10.1039/c4py00767k

Abstract

The influence of the carborane isomer and double bond geometry on the optoelectronic properties for a series of side chain functionalised polythiophenes is reported.

Highlights

Research undertaken by Liu, Li and co-workers demonstrated that polymeric absorption spectrum could be broadened by replacing an hexyl sidechain with an hexy-1-enyl unit, facilitating the improved absorption of incident photons and an improvement in photovoltaic power conversion efficiency.[12]
We report the synthesis of a series of novel polythiophenes with vinylene linked pendant carborane sidechains
The synthesis of ortho/cis and ortho/trans monomers is shown in Scheme 1 and follows a Wittig strategy to attach carborane to the thiophene monomer via a double bond.[34]

Summary

Introduction

Research undertaken by Liu, Li and co-workers demonstrated that polymeric absorption spectrum could be broadened by replacing an hexyl sidechain with an hexy-1-enyl unit, facilitating the improved absorption of incident photons and an improvement in photovoltaic power conversion efficiency.[12]. Sublimed ortho-carborane (7.5 g, 52 mmol) was dissolved in anhydrous diethyl ether (150 mL) and cooled to −78 °C To this solution was added n-BuLi (36 mL of 1.6 M in hexanes, 57.6 mmol) slowly, before the mixture was stirred at −78 °C for 2.5 h. Sublimed meta-carborane (6.0 g, 41.7 mmol) was dissolved in anhydrous diethyl ether (100 mL) and cooled to −78 °C To this solution was added n-BuLi (28.8 mL of 1.6 M in hexanes, 46.1 mmol) slowly before the reaction mixture was stirred at −78 °C for 2.5 h. Sublimed para-carborane (1.56 g, 10.8 mmol) was dissolved in anhydrous diethyl ether (10 mL) and cooled to −78 °C To this solution was added n-BuLi (7.4 mL of 1.6 M in hexanes, 11.9 mmol) slowly before the reaction mixture was stirred at −78 °C for 2.5 h. Elemental analysis: calculated for C8H14B10Br2S2, C, 23.43; H, 3.44; found: C 23.36; H 3.34

Polymerisation procedure

Results and discussion

Conclusions