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Interstate Crossing‐Induced Chemiexcitation as the Reason for the Chemiluminescence of Dioxetanones
Author(s) -
Pinto da Silva Luís,
Esteves da Silva Joaquim C. G.
Publication year - 2013
Publication title -
chemphyschem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.016
H-Index - 140
eISSN - 1439-7641
pISSN - 1439-4235
DOI - 10.1002/cphc.201200872
Subject(s) - intersystem crossing , excited state , singlet state , chemiluminescence , photochemistry , chemistry , singlet fission , population , triplet state , ground state , chemical physics , atomic physics , physics , demography , sociology
The decomposition reaction of dimethyl‐1,2‐dioxetanone in dichloromethane was studied by using a DFT approach. The low efficiency of triplet and singlet excited‐state formation was rationalised. A charge‐transfer process was demonstrated to be involved in the chemiluminescence process. Present and previous results allow us to define an interstate crossing‐induced chemiexcitation (ICIC) mechanism for the chemiluminescence of dioxetanones. Charge transfer is needed to reach a transition state, in the vicinity of which direct population of excited states is possible. The chemiexcitation process is then governed by singlet/triplet intersystem crossings. Structural modifications then modify the rate of these crossings and the singlet ground and excited‐state interaction, thereby modulating the efficiency of this process and the spin of the resulting products.