4-Fluorophenyl Tagging as a Diagnostic Tool for Monitoring Sulfur Oxidation States via 19F NMR

We report a simple and general strategy to monitor sulfur oxidation states using 19 F NMR by incorporating a 4-fluorophenyl tag on sulfur-containing molecules. A series of structurally related compounds spanning various sulfur oxidation states were compiled, and their 19 F NMR chemical shifts were recorded to establish a diagnostic fingerprint tool. This approach enables rapid characterization of products and byproducts in sulfur-based transformations, particularly those involving redox changes such as disproportionation. To demonstrate the utility of the method, we applied it to study reactions involving sulfur oxidation state changes, establishing a proof-of-concept for this diagnostic platform. This technique offers a valuable tool for mechanistic analysis and product profiling in diverse areas of sulfur chemistry.