{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,1,30]],"date-time":"2026-01-30T02:54:13Z","timestamp":1769741653904,"version":"3.49.0"},"reference-count":91,"publisher":"MDPI AG","issue":"8","license":[{"start":{"date-parts":[[2023,4,18]],"date-time":"2023-04-18T00:00:00Z","timestamp":1681776000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"Ministerio de Ciencia e Innovaci\u00f3n","award":["PID2020-113147GA-I00"],"award-info":[{"award-number":["PID2020-113147GA-I00"]}]},{"name":"Ministerio de Ciencia e Innovaci\u00f3n","award":["PID2021-122549NB-C22"],"award-info":[{"award-number":["PID2021-122549NB-C22"]}]},{"name":"Ministerio de Ciencia e Innovaci\u00f3n","award":["EDU\/601\/2020"],"award-info":[{"award-number":["EDU\/601\/2020"]}]},{"name":"Fundaci\u00f3n Salamanca City of Culture and Knowledge","award":["PID2020-113147GA-I00"],"award-info":[{"award-number":["PID2020-113147GA-I00"]}]},{"name":"Fundaci\u00f3n Salamanca City of Culture and Knowledge","award":["PID2021-122549NB-C22"],"award-info":[{"award-number":["PID2021-122549NB-C22"]}]},{"name":"Fundaci\u00f3n Salamanca City of Culture and Knowledge","award":["EDU\/601\/2020"],"award-info":[{"award-number":["EDU\/601\/2020"]}]},{"DOI":"10.13039\/501100014180","name":"Junta de Castilla y Leon and European Social Fund","doi-asserted-by":"publisher","award":["PID2020-113147GA-I00"],"award-info":[{"award-number":["PID2020-113147GA-I00"]}],"id":[{"id":"10.13039\/501100014180","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100014180","name":"Junta de Castilla y Leon and European Social Fund","doi-asserted-by":"publisher","award":["PID2021-122549NB-C22"],"award-info":[{"award-number":["PID2021-122549NB-C22"]}],"id":[{"id":"10.13039\/501100014180","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100014180","name":"Junta de Castilla y Leon and European Social Fund","doi-asserted-by":"publisher","award":["EDU\/601\/2020"],"award-info":[{"award-number":["EDU\/601\/2020"]}],"id":[{"id":"10.13039\/501100014180","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["IJMS"],"abstract":"<jats:p>The deprotonation of an organic substrate is a common preactivation step for the enzymatic cofactorless addition of O2 to this substrate, as it promotes charge-transfer between the two partners, inducing intersystem crossing between the triplet and singlet states involved in the process. Nevertheless, the spin-forbidden addition of O2 to uncharged ligands has also been observed in the laboratory, and the detailed mechanism of how the system circumvents the spin-forbiddenness of the reaction is still unknown. One of these examples is the cofactorless peroxidation of 2-methyl-3,4-dihydro-1-naphthol, which will be studied computationally using single and multi-reference electronic structure calculations. Our results show that the preferred mechanism is that in which O2 picks a proton from the substrate in the triplet state, and subsequently hops to the singlet state in which the product is stable. For this reaction, the formation of the radical pair is associated with a higher barrier than that associated with the intersystem crossing, even though the absence of the negative charge leads to relatively small values of the spin-orbit coupling.<\/jats:p>","DOI":"10.3390\/ijms24087424","type":"journal-article","created":{"date-parts":[[2023,4,18]],"date-time":"2023-04-18T02:30:03Z","timestamp":1681785003000},"page":"7424","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":8,"title":["Spin-Forbidden Addition of Molecular Oxygen to Stable Enol Intermediates\u2014Decarboxylation of 2-Methyl-1-tetralone-2-carboxylic Acid"],"prefix":"10.3390","volume":"24","author":[{"ORCID":"https:\/\/orcid.org\/0000-0003-2480-6220","authenticated-orcid":false,"given":"Pablo","family":"Ortega","sequence":"first","affiliation":[{"name":"Departamento de Qu\u00edmica-F\u00edsica, Universidad de Salamanca, 37008 Salamanca, Spain"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-1747-4048","authenticated-orcid":false,"given":"Sara","family":"Gil-Guerrero","sequence":"additional","affiliation":[{"name":"Departamento de Qu\u00edmica-F\u00edsica, Universidad de Salamanca, 37008 Salamanca, Spain"},{"name":"CICECO\u2014Aveiro Institute of Materials, University of Aveiro, 3810-193 Aveiro, Portugal"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-7800-5739","authenticated-orcid":false,"given":"Lola","family":"Gonz\u00e1lez-S\u00e1nchez","sequence":"additional","affiliation":[{"name":"Departamento de Qu\u00edmica-F\u00edsica, Universidad de Salamanca, 37008 Salamanca, Spain"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-2713-5875","authenticated-orcid":false,"given":"Cristina","family":"Sanz-Sanz","sequence":"additional","affiliation":[{"name":"Departamento de Qu\u00edmica F\u00edsica Aplicada, Universidad Aut\u00f3noma de Madrid, 28049 Madrid, Spain"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-8846-3998","authenticated-orcid":false,"given":"Pablo G.","family":"Jambrina","sequence":"additional","affiliation":[{"name":"Departamento de Qu\u00edmica-F\u00edsica, Universidad de Salamanca, 37008 Salamanca, Spain"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2023,4,18]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"207","DOI":"10.1021\/acs.accounts.0c00606","article-title":"Heavy-Atom-Free Photosensitizers: From Molecular Design to Applications in the Photodynamic Therapy of Cancer","volume":"54","author":"Nguyen","year":"2020","journal-title":"Acc. 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