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Photochemical free radical formation from aliphatic dicarboxylic acids in solution as studied by electron spin resonance spectroscopy
Author(s) -
Wymann Lotty,
Kaiser Tony,
Paul Henning,
Fischer Hanns
Publication year - 1981
Publication title -
helvetica chimica acta
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.74
H-Index - 82
eISSN - 1522-2675
pISSN - 0018-019X
DOI - 10.1002/hlca.19810640604
Subject(s) - chemistry , radical , photochemistry , electron paramagnetic resonance , spectroscopy , bond cleavage , aqueous solution , solvent , triplet state , organic chemistry , molecule , catalysis , nuclear magnetic resonance , physics , quantum mechanics
Various free radicals formed during UV.‐irradiation of aliphatic dicarboxylic acids in aqueous and methanolic solution are identified by ESR.‐spectroscopy. Their structures point to α‐cleavage and photoreduction as the dominant primary photochemical decay processes. The relative contributions of these reactions to the overall photodecomposition depend on solvent and degree of α‐alkylation of the acid. Emission ESR.‐spectra are found for radicals formed by C, CO‐bond cleavage of α‐dimethyl substituted acids. The polarization is referred to the triplet mechanism of CIDEP. and indicates this cleavage reaction occurs from a triplet molecular state.