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)Cl2 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 M ₙ of the polymer was controlled by the feed ratio of 1 to Ni(dppp)Cl2. 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. image GPC profiles of HT‐P3HT obtained after quenching with water and 5 M hydrochloric acid, respectively.