Porphyrinic Metal-Organic Frameworks for the Photocatalytic Degradation of a Mustard Gas Simulant

Sulfur mustard is a toxic chemical warfare agent that is most known for its use in World War I. Today, stockpiles of sulfur mustard exist around the world and need to be safely and efficiently degraded. One efficient solution is to selectively oxidize sulfur mustard into a nontoxic product using metal-organic frameworks (MOFs). These are porous, crystalline materials that can be designed for a variety of applications such as photocatalysis. MOFs with porphyrinic linkers in particular have shown promise for the photocatalytic degradation of a simulant of sulfur mustard (CEES), into its nontoxic sulfoxide form (CEESO). In this study, four metallporphyrins and four metalloporphyrinic MOFs called PCN-222(M) were synthesized, characterized, and tested for their efficacy in converting CEES into CEESO in methanol and acetonitrile. The MOFs were made with porphyrins doped with M = manganese, copper, tin, or indium. It was determined that generally, the MOFs achieved faster rates of CEES conversion compared to their respective metalloporphyrins. In methanol, in order from fastest to slowest CEES conversion were PCN-222(Sn), PCN-222(In), PCN-222(Mn), and PCN-222(Cu). The selectivity for nontoxic sulfoxides in acetonitrile-d3 was also determined.