Spray Processable Hybrid 3,4-Propylenedioxythiophene: Phenylene Electrochromic Polymers

The optical and redox properties of a new family of thiophene−phenylene-based molecules are reported. The monomers 1,4-bis[2-(3,3-dimethyl-(3,4-propylenedioxy)thienyl]-2,5-didodecyloxybenzene (BProDOT-Me2-B(OC12H25)2) and 1,4-bis[2-(3,3-dihexyl-(3,4-propylenedioxy)thienyl]-2,5-didodecyloxybenzene (BProDOT-Hex2-B(OC12H25)2) have been synthesized via Negishi coupling of the alkyl-substituted ProDOT and didodecyloxyphenylene units in ca. 40% yields. They were efficiently electropolymerized to form electroactive films which exhibit redox switching at fairly low potentials (∼+0.1 V vs Fc/Fc+). BProDOT-Hex2-B(OC12H25)2) was polymerized via ferric chloride-mediated chemical oxidation and the polymer isolated after dedoping with hydrazine. A number-average molecular weight of 14 600 g/mol was estimated using size exclusion chromatography, and the polymer structure was confirmed by MALDI mass spectrometry. The polymer is highly soluble in chloroform, THF, and toluene, and homogeneous films were prepared by spin-co...