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Struktur und photochemische Reaktivität: Photohydrolyse von Trifluormethylsubstituierten Phenolen und Naphtholen
Author(s) -
Seiler P.,
Wirz J.
Publication year - 1972
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.19720550802
Subject(s) - chemistry , heterolysis , excited state , flash photolysis , singlet state , reactivity (psychology) , photochemistry , photodissociation , triplet state , ground state , quenching (fluorescence) , molecule , reaction rate constant , kinetics , fluorescence , organic chemistry , atomic physics , catalysis , quantum mechanics , pathology , medicine , physics , alternative medicine
Irradiation of trifluoromethylphenols (three isomers) and ‐naphthols (eight isomers) in water solution yields the corresponding hydroxybenzoic and naphthoic acids, respectively. The reaction mechanism has been investigated by means of flash photolysis and quenching experiments. It is proposed that the photohydrolysis is initiated in the lowest excited singlet state by a heterolytic CF bond cleavage. The observed photochemical and thermal reaction rates as well as the shifts of the lowest electronic transitions upon CF 3 ‐substitution compare well with predictions from semiempirical π‐electron calculations (PPP SCF CI). A rationale for the correlation between excited state charge densities and photochemical reactivity is given. pK values for the ground state and first excited singlet state are reported.