Can the Closed-Shell DFT Methods Describe the Thermolysis of 1,2-Dioxetanone?
2012 (English)In: Journal of Chemical Theory and Computation, ISSN 1549-9618, E-ISSN 1549-9626, Vol. 8, no 11, 4359-4363 p.Article in journal (Refereed) Published
The chemiluminescent decomposition of 1,2-dioxetanone has in the past been studied by state-of-the-art multireference quantum chemical calculations, and a stepwise biradical mechanism was established. Recently, this decomposition has been reinvestigated, and a concerted mechanism has been proposed based on calculations performed at the closed-shell density functional theory (DFT) level of theory. In order to solve this apparent mechanistic contradiction, the present paper presents restricted and unrestricted DFT results obtained using functionals including different amounts of Hartreeâ€“Fock (HF) exchange, repeating and complementing the above-mentioned DFT calculations. The calculated results clearly indicate that the closed-shell DFT methods cannot correctly describe the thermolysis of 1,2-dioxetanone. It is found that unrestricted Kohnâ€“Sham reaction energies and barriers are always lower than the ones obtained using a restricted formalism. Hence, from energy principles, the biradical mechanism is found to be prevailing in the understanding of the 1,2-dioxetanone thermolysis.
Place, publisher, year, edition, pages
2012. Vol. 8, no 11, 4359-4363 p.
IdentifiersURN: urn:nbn:se:uu:diva-181531DOI: 10.1021/ct3006562ISI: 000311191900037OAI: oai:DiVA.org:uu-181531DiVA: diva2:556536