Sustainable Functionalization of Pyrene: A Green Chemistry Approach for Advanced Materials
Description
Substituted pyrene compounds are versatile building blocks for advanced materials with tunable properties, applicable in organic photovoltaics (OPVs), organic light-emitting diodes (OLEDs), precursors to metal-organic frameworks (MOFs) for luminescence sensing, photocatalysis, and electrochemical applications. Direct functionalization of pyrene can suffer from regioselectivity issue while indirect methods offer greater regiochemical control but add complexity. This motivates the development of alternative approaches, such as the DMSO-based strategy explored in our research where it acts a source of the methyl (methylene) sulfonium cation, an intermediate with a positively charged sulfur atom bonded to methyl and methylene groups and facilitates diverse transformations due to sulfur's ability to stabilize adjacent negative charge. Our strategy involves activating DMSO to generate the cation, followed by electrophilic aromatic substitution with pyrene. Subsequent transformations enable the introduction of various functionalities, including aldehydes, sulfoxides, and carboxylic acids, expanding the utility of pyrene derivatives. This study explores a novel DMSO-based methodology for the controlled functionalization of pyrene. DMSO serves as a masked formyl group equivalent, enabling efficient production of mono-, di-, tri-, and tetra-substituted pyrene aldehydes, along with pyrene sulfoxides and sulfides, thus broadening their application in advanced material development.