Synthesis of Poly(3‐hexylthiophene) with a Narrower Polydispersity

Summary: The polymerization of 2‐bromo‐3‐hexyl‐5‐iodothiophene ( 1 ) with isopropylmagnesium chloride and Ni(dppp)Cl 2 was quenched with 5 M hydrochloric acid instead of water to yield head‐to‐tail poly(3‐hexylthiophene) (HT‐P3HT) with a very low polydispersity. The $\overline M _{\rm n}$ of the polymer was controlled by the feed ratio of 1 to Ni(dppp)Cl 2 . Quenching with 5 M hydrochloric acid seemed to promote protonolysis of HT‐P3HT‐Ni complexes before the coupling reaction between HT‐P3HT.GPC profiles of HT‐P3HT obtained after quenching with water and 5 M hydrochloric acid, respectively.