Investigating the Potency of a Phenalenyl-Based Photocatalyst under the Photoelectrochemical Condition for Intramolecular C–S Bond Formation

Implementation of an organic molecular photocatalyst for photoelectrochemical (PEC) transformations has been a highly demanding aspect that has not yet been mapped out extensively. Herein, we have unveiled the efficacy of a phenalenyl-based organic photocatalyst toward photoelectrochemical intramolecular C–S bond construction reactions under mild conditions. This phenalenyl core, which contains a vacant NBMO, acts as an electron reservoir, thereby facilitating the formation of a contact ion pair with electron-rich organic systems through intramolecular electron transfer under photoexcitation and aiding in catalytic regeneration by anodic oxidation in a single pot. Detailed mechanistic investigation by using UV–visible spectral analysis, cyclic voltammetry experiments, and computational calculations revealed that the prior formation of an EDA complex between the phenalenyl-based photocatalyst and substrate triggers this PEC process. This unified strategy was successfully implemented in six different intramolecular C–S bond formation reactions to synthesize different heterocycles and make this protocol appealing for the synthesis of C–S bonds.