Effects of Azo Bridge and Substituents on the Electrochemical and Spectral Properties of Bis(triarylamine)s

4,4′-Azo-bis(triarylamine) derivatives with electron-donating groups have been synthesized. Their spectral and electrochemical characteristics have been investigated. Their first and second oxidations exhibited different degrees of overlapping, depending on the electron-donating groups at the para-position of the phenyl rings. The stability of the oxidation products was monitored with UV/VIS/NIR spectro-electrochemical methods. The derivatives have much stronger IV-CT bands in the near-IR range. The spectral change reveals the number of electron transfer in the stepwise oxidation and the stability of the products.