Electrosynthesis and electrochromic properties of poly(amide-triarylamine)s containing triptycene units

Four bis(amide-triarylamine) derivatives featuring a triptycene as an interior core and terminal electroactive triphenylamine (TPA) or N-phenylcarbazole (NPC) groups were prepared by the condensation reactions from 1,4-bis(4-aminophenoxy)triptycene with 4-carboxytriphenylamine and N-(4-carboxyphenyl)carbazole, respectively, and from 1,4-bis(4-carboxyphenoxy)triptycene with 4-aminotriphenylamine and N-(4-aminophenyl)carbazole, respectively. The electrochemistry and electropolymerization of these bis(amide-triarylamine) derivatives were investigated. The stability of the oxidized forms of the bis(amide-triarylamine)s is affected by the orientation of amide linkage and the structure of terminal triarylamine unit. Two of the bis(amide-triarylamine)s could be electropolymerized into robust films on the electrode surface in an electrolyte solution. The electrogenerated polymer films exhibited reversible electrochemical oxidation processes and strong color changes upon electro-oxidation, which can be switched by potential modulation. The electrochromic properties of the films were evaluated by the spectroelectrochemical and electrochromic switching studies. The TPA-based film showed better electrochromic performance than the NPC-based one.