An Atomically Dispersed Mn Photocatalyst for Vicinal Dichlorination of Nonactivated Alkenes.

A novel Mn-based single-atom photocatalyst is disclosed in this study, designed for the dichlorination of alkenes to achieve vicinal dichlorinated products using N-chlorosuccinimide as a mild chlorinating agent, which have widespread applications as pest controlling agents, polymers, flame retardants, and pharmaceuticals. In developing this innovative catalyst, we achieved the atomic dispersion of Mn on aryl-amino-substituted graphitic carbon nitride (f-C3N4). This marks the first instance of a heterogeneous version, offering an operationally simple, sustainable, and efficient pathway for dichlorination of alkenes, including drugs, bioactive compounds, and natural products. This material was extensively characterized by using techniques such as UV-vis spectroscopy, X-ray absorption near-edge structure (XANES), extended X-ray absorption fine structure (EXAFS), high-resolution transmission electron microscopy (HR-TEM), X-ray photoelectron spectroscopy (XPS), magic-angle spinning (MAS), and solid-state nuclear magnetic resonance (ssNMR) spectroscopy to understand it at the atomic level. Furthermore, mechanistic studies based on multiscale molecular modeling, combining classical reactive molecular dynamics (RMD) simulations and quantum chemistry (QC) calculations, illustrated that the controlled formation of Cl radicals from the in situ formed Mn-Cl bond is responsible for the dichlorination reaction of alkenes. In addition, gram-scale and reusability tests were also performed to demonstrate the applicability of this approach on an industrial scale.