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

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 ill situ replacement of the bipyridyl ligand onto bidentate phosphorus one.