Synthesis of a Bifunctional Initiator for Controlled Kumada Catalyst-Transfer Polycondensation/Nitroxide-Mediated Polymerization and Preparation of Poly(3-hexylthiophene)−Polystyrene Block Copolymer Therefrom

Abstract

Herein, we present a new approach to synthesize rod−coil block copolymers via consecutive Kumada catalyst-transfer polycondensation (KCTP) and nitroxide-mediated free radical polymerization (NMP) performed from a bifunctional initiator, TIPNO−Ph−Ni(dppp)−Br (TIPNO = 2,2,5-trimethyl-4-phenyl-3-azahexane-3-nitroxide; dppp = propane-1,3-diylbis(diphenylphosphane). The utility of the method was exemplified in a preparation of a model block copolymer, poly(3-hexylthiophene)- block -polystyrene (P3HT- b -PS) with a relatively narrow molecular weight distribution of 1.33. Synthesis of the bifunctional initiator was accomplished by a reaction of diethylbipyridylnickel with a readily accessible precursor, TIPNO−Ph−Br, followed by in situ replacement of the bipyridyl ligand onto bidentate phosphorus one.