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Chemiexcitation without the Peroxide Bond? Replacing Oxygen with other Heteroatoms
Author(s) -
Fdez. Galván Ignacio,
Gustafsson Hannes,
Vacher Morgane
Publication year - 2019
Publication title -
chemphotochem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.13
H-Index - 18
ISSN - 2367-0932
DOI - 10.1002/cptc.201800232
Subject(s) - peroxide , dioxetane , chemistry , photochemistry , molecule , excited state , chemiluminescence , population , computational chemistry , atomic physics , organic chemistry , physics , demography , sociology
Chemiexcitation is the population of electronic excited states from the electronic ground state via radiationless non‐adiabatic transitions upon thermal activation. The subsequent emission of the excess of energy in the form of light is called chemiluminescence or bioluminescence when occurring in living organisms. Key intermediates in these reactions have been shown to contain a high‐energy (often cyclic) peroxide which decomposes. The simplest molecules, 1,2‐dioxetane and 1,2‐dioxetanone, have thus been used extensively both theoretically and experimentally as model systems to understand the underlying mechanisms of chemiexcitation. An outstanding question remains whether the peroxide bond is a necessity and whether equivalent processes could happen in other simple molecules not containing an O−O bond. In the present work, the decomposition reactions of four analogs of 1,2‐dioxetane not containing a peroxide bond, the 1,2‐oxazetidine anion, the 1,2‐diazetidine anion, (neutral) 1,2‐oxazetidine and 1,2‐dithietane, have been studied theoretically using ab initio multiconfigurational methods. In particular, the reaction energy barriers and spin‐orbit coupling strengths were calculated; the electronic degeneracy was studied and compared to the case of 1,2‐dioxetane to assess the potentiality of chemiexcitation in the analog molecules.