State of partial oxidation of the regioregular sexi (3-octyl thiophene) oligomer in solid phase on electrode surface

An existence of a new, stable oligomer state of the solid film is reported, which is produced under electrochemical conditions. In this state, a formal charge exchanged in the redox process is about one-half of electron per oligomer molecule. The procedure, which allows controlling precisely the amount of oligomer on the electrode surface, is proposed that together with the coulometric evaluation of the electric charge provides the number of electrons involved in a redox process. This is demonstrated for a case of α-monochloro-substituted regioregular sexi (3-octylthiophene) oligomer (6OTCl). The electrochemical results are discussed together with UV-Vis-NIR spectroelectrochemical data obtained for both solution and solid phase that support the proposed interpretation.