The regioselective halogen–magnesium exchange reaction of 4-(5″-hexylpyridine-2″-yl)-3-methoxy-2-(5′-bromothiophene-2′-yl)-5-bromothiophene (M3) with i-PrMgCl·LiCl, Kumada coupling polymerization using Ni(dppp)Cl2 at the refluxing temperature and optoelectronic characterization of regiocontrolled oligo(bithiophene) (P3′) were investigated. The ultraviolet–visible and cyclic voltammogram measurements indicated that P3′ has the more planar conformation, increased highest occupied molecular orbital energy level and narrower bandgap energy as compared with a polythiophene derivative without the methoxy group. The non-covalent S···O interaction was supposed to be a reason for the planar conformation, which was supported by the theoretical density functional theory calculation.
- Koji Takagi
- Ryo Kouchi
- Junpei Kawai
