Effect of N-α Substitution on the Electropolymerization of N-Substituted Pyrroles: Structure–Reactivity Relationship Studies

Abstract

Structure–reactivity relationship (SRR) studies to understand the effect of N-α substitution toward electroactive poly(pyrrole) film formation have carefully been performed. To conduct these SRR studies, a selected chemical library of 21 different N-substituted pyrrole derivatives has been developed using the key well-known Clauson–Kass synthetic reaction from corresponding amine precursors. While investigating electropolymerization features of these novel N-substituted pyrroles, we observed that the steric factor due to α-substitution, one among other factors, plays the most significant role in preventing electropolymerization of these oxidizable chemical species. Interestingly, even a sterically small chemical group like a CH3 one present at α-position is large enough to prevent monomer electropolymerization. Density functional theory calculations were carried out to analyze the polymerization of substituted pyrrole molecules and to understand the effect of N-substituents on electropolymerization toward...