Electrochemical reduction reaction mechanism of cinnamonitrile

The electroreduction of cinnamonitrile in MeCN solution was studied using cyclic voltammetry, with two reduction peaks at -1.46 and -2.0 V. Linear, cyclic hydrodimers, and 3-phenyl pentanedinitrile were synthesized at the first peak, while additional saturated hydro product was synthesized at the second peak. The reduction mechanism was proposed based on the experimental and cyclic voltammogram simulation results. Linear and cyclic hydrodimers were synthesized by a radical-radical (RR) route while a saturated hydro product was obtained via an electrochemical- electrochemical-chemical-chemical (EECC) process. 3-Phenyl pentanedinitrile was synthesized by the reaction of cinnamonitrile with the conjugate base of MeCN. Finally, the dynamic constants were calculated using cyclic voltammogram simulation. Result indicated that the rate constant of the RR reaction was found to be 10⁴ L· mol^-1· s^-1, and the rate constant of the second electron transfer reaction was 0.3 cm· s^-1, while the rate constant of the subsequent proton reaction was 10⁵ s^-1.