Polythiophenes bearing a siloxane moiety in a substituent at the 3-position are prepared by deprotonative polycondensation of 2-bromo-3-substituted-thiophene with a bulky magnesium amide chloromagnesium 2,2,6,6-tetramethylpiperidine-1-yl lithium chloride salt (TMPMgCl•LiCl) catalyzed by a nickel complex. Deprotonation takes place at 60 °C for 1 h to form the corresponding thiophene magnesium species, which is subjected to the polymerization by addition of 0.1−5 mol % NiCl 2 (PPh 3 )IPr (IPr: 1,3-bis(2,6-diisopropylphenyl)imidazole-2-yl). Polymerization proceeds in a highly regioregular manner, and the molecular weight of the thus-obtained polymer is controllable by the ratio of monomer feed/ catalyst loading to indicate M n of up to 280 000 with narrow molecular weight distribution. Chlorothiophenes are also found to induce polymerization in a deprotonative manner with TMPMgCl•LiCl or nBuLi (the Murahashi coupling polymerization). The obtained polymers bearing a siloxane moiety in the substituent is revealed to be dissolved in a hydrocarbon allowing formation of thin film from hexane.

Polymerization of thiophene with a Ni(ii) catalyst through halogen dance leads to a new class of polythiophenes.

A simple and ubiquitous nickel(II) complex NiCl 2 (PPh 3) 2 catalyzes polymerization of oligothiophenes. Treatment of chlorobithiophene with chloromagnesium 2,2,6,6-tetramethylpiperidin-1-yl lithium chloride salt (TMPMgCl¢LiCl) followed by addition of 2.0 mol % NiCl 2 (PPh 3) 2 undergoes deprotonative polymerization leading to poly(3-hexylthiophene) (P3HT) with M n = 13000 and M w /M n = 1.67 (74% yield). The related terthiophene and quaterthiophene also polymerize to afford the corresponding polythiophene while little polymerization takes place with 2-chloro-3-hexylthiophene under similar conditions.