radicalmediated

Radical-mediated describes a class of chemical and biological processes in which reactive radical species serve as the principal intermediates that drive the reaction sequence. Radicals are atoms or molecules with unpaired electrons; they can be generated by heat, light, redox reactions, or catalytic steps. Reactions proceed through initiation, propagation, and termination steps, often yielding products with high reactivity or low selectivity.

In chemistry, radical-mediated mechanisms underpin free-radical polymerization, radical rearrangements, and various oxidation or functionalization reactions. Initiators such as benzoyl peroxide or azo compounds generate radicals that add to unsaturated substrates, propagating chain growth or cross-linking. In environmental and industrial settings, radical-mediated oxidation by hydroxyl or sulfate radicals participates in pollutant degradation and material synthesis.

In biology and medicine, radical-mediated processes relate to reactive oxygen and nitrogen species that can modify lipids, proteins, and DNA. While controlled radical signaling plays roles in normal physiology, excessive radical production causes oxidative stress associated with aging and disease. Cells employ antioxidants and repair pathways to limit damage and restore homeostasis.

Detection and study of radical-mediated processes rely on spectroscopic methods such as electron spin resonance (ESR) and time-resolved spectroscopy, as well as trapping techniques that convert short-lived radicals into detectable adducts. The term emphasizes the mechanism rather than a single reaction type, and its applications range from synthetic chemistry to toxicology and environmental science.