Synthesis of 4,5-Disubstituted <i>o</i> -Phenylenediamines: An Enabling Platform for Electrochemical Investigations of Interfacial Ion Transfer Reactions

<i>O</i>-phenylenediamines have emerged as powerful synthons for the installation of molecularly well-defined active sites conjugated to graphitic carbon electrode surfaces. These graphite-conjugated actives sites can serve as rich platforms for the electrochemical investigation of interfacial ion transfer reactions at the molecular level. But widespread utilization of this platform is restricted by the limited synthetic access to <i>o</i>-phenylenediamines bearing an array of additional functional groups. Herein, we present three distinct and modular synthetic strategies to symmetric and asymmetric 4,5-<i>o</i>-phenylenediamines. We demonstrate the utility of 4,5-<i>o</i>-dinitrobenzenes as relatively stable precursors to this class of compounds, as well as a modular route to 4,5-<i>o</i>-phenylenediamines in as little as 2 steps from commercial starting materials. We then show, using cyclic voltammetry, that graphitic electrodes modified with molecules obtained from our syntheses exhibit expected electrochemical responses.