(extra high purity,
water content <0.3%, Cryochrom) was used to prepare solutions.
Bu4NClO4 (≥99%, for electrochemical analysis)
was purchased from Sigma-Aldrich and used as a background electrolyte.
Cyclohexanone, cyclopentanone, benzaldehyde, 4-methoxybenzaldehyde,
3,4-dimethoxybenzaldehyde, 4-(methylthio)benzaldehyde, 4-dimethylaminobenzaldehyde,
and 4-diethylaminobenzaldehyde (Sigma-Aldrich) were used as received.
EtOH (chemically pure) was used without additional purification, and
(2E,6E)-2,6-bis(3,4-dimethoxybenzylidene)cyclopentanone
(