Differential features of short-lived intermediates: Structure, properties and reactivity

Some general features of short-lived intermediates that can be useful when facing mechanistic studies or other projects involving these species are briefly revised, with special attention to properties of neutral radicals, radical cations, radical anions and excited states that condition the fate of the process. Some case studies related to molecules or families of molecules that are of technological relevance are presented: triazine-based radicals, radical cations of enol ethers, aminium and aminyl radicals derived from amino acids. We show how experimental and computational information about short-lived species, their structure and thermodynamic properties, can help control the reactivity and thermodynamics of chemical reactions.