4-Phenyl-4H-1,2,4-triazoline-3,5-dione, an efficient spin trap for carbon- and metal-centered radicals

The spin adducts between a variety of organic or organometallic radicals and 4-phenyl-4H-1,2,4-triazoline-3,5-dione (Ph-TAD) have been investigated by ESR spectroscopy. Because of its reactivity toward metal-centered radicals which do not easily add to nitroso derivatives or nitrones, Ph-TAD can provide a valuable alternative to these more popular radical scavengers. The ambiguity present in the literature about the ESR parameters of some of the resulting 4-phenylurazolyl radicals is discussed. © 1983 American Chemical Society.