Charge resonance excitations in 1,3-bis[di(4-methoxyphenyl)aminolazulene radical cations
The 1,3-bis[di(4-methoxyphenyl)amino]azulene 1 and 1,3-bis[di(4-methoxyphenyl)amino]azulene-2-carboxylic acid methyl ester 2 were synthesized and investigated by spectroscopic and electrochemical methods in order to estimate the electronic coupling between the attached amine redox centers. We found that the electronic coupling V which is mediated by a nonalternant 1,3-azulene bridge in the radical