{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,23]],"date-time":"2026-09-23T16:06:14Z","timestamp":1790179574470,"version":"4.1.0"},"reference-count":50,"publisher":"American Chemical Society (ACS)","issue":"5","license":[{"start":{"date-parts":[[2026,8,3]],"date-time":"2026-08-03T00:00:00Z","timestamp":1785715200000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"Universidad de M?laga\/CBUA"},{"name":"Spanish Ministry of Science and Innovation"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":[],"published-print":{"date-parts":[[2026,9,23]]},"abstract":"<jats:title>Abstract<\/jats:title>\n                  <jats:p>The photochemical formation of carbenes from 3-phenyl-3-(trifluoromethyl)-3H-diazirine (1) and its diazo isomer, phenyl-trifluoromethyl-diazomethane (2), was investigated using high-level multiconfigurational wave function methods (MS-CASPT2) and density functional theory (DFT). Vertical excitation energies and the vibronic absorption spectrum of 1 were computed, confirming that the experimental signals reported in the literature originate from a single conformer. Our results demonstrate that S1 excitation in both isomers leads to ultrafast nonradiative deactivation through a shared S1\/S0 conical intersection (CI1). In the condensed phase, this relaxation triggers a branching mechanism: the system can either revert to the precursor, undergo diazirine\u2013diazo isomerization, or fragment into N2 and a closed-shell singlet carbene. Notably, the topology of the ground-state potential energy surface suggests that CI1 is a primary connection between the two isomers, relegating a conventional transition-state-mediated pathway to a less likely alternative for isomerization. Furthermore, a comparative assessment shows that both MS-CASPT2 and DFT provide consistent descriptions of the critical S1\/S0 and S0\/T0 crossing geometries. These findings provide a comprehensive mechanistic framework for the photolysis of aryl-trifluoromethyl diazirines.<\/jats:p>","DOI":"10.1021\/acsphyschemau.6c00069","type":"journal-article","created":{"date-parts":[[2026,8,4]],"date-time":"2026-08-04T14:36:59Z","timestamp":1785854219000},"page":"1235-1243","source":"Crossref","is-referenced-by-count":0,"title":["Mechanistic\nInsights into the Photochemical Formation\nof Carbenes from Phenyl-trifluoromethyl Diazirine and Its Diazo Isomer:\nAn MS-CASPT2 Study"],"prefix":"10.1021","volume":"6","author":[{"ORCID":"https:\/\/orcid.org\/0000-0001-6702-2878","authenticated-orcid":true,"given":"Juan","family":"Soto","sequence":"first","affiliation":[{"name":"University of Ma\u0301laga , , Andaluci\u0301a Tech. , ,","place":["Ma\u0301laga, Spain, E-29071"]},{"name":"University Institute of Materials and Nanotechnology (IMANA). University of Ma\u0301laga , Campus de Teatinos , ,","place":["Ma\u0301laga, Spain, E-29071"]}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"316","published-online":{"date-parts":[[2026,8,3]]},"reference":[{"key":"2026092310072448400_cit1","doi-asserted-by":"publisher","first-page":"83","DOI":"10.1021\/acsorginorgau.1c00027","article-title":"Emerging Applications of Aryl Trifluoromethyl Diazoalkanes\nand Diazirines in Synthetic Transformations","volume":"2","author":"Ollevier","year":"2022","journal-title":"ACS Org. Inorg. Au"},{"key":"2026092310072448400_cit2","doi-asserted-by":"publisher","first-page":"3313","DOI":"10.1016\/S0021-9258(19)85701-0","article-title":"3-Trifluoromethyl-3-\nphenyldiazirine.\nA new carbene generating group for photolabeling reagents","volume":"255","author":"Brunner","year":"1980","journal-title":"J. Biol. Chem."},{"key":"2026092310072448400_cit3","doi-asserted-by":"publisher","DOI":"10.1002\/poc.4298","article-title":"Wavelength-dependent photochemistry\nof 1-phenyl-1-diazopropane","volume":"35","author":"Tokihiro","year":"2021","journal-title":"J. Phys. Org. Chem."},{"key":"2026092310072448400_cit4","unstructured":"Luk, H. L.\n          \n          Computational\nand Experimental Studies of Excited States of Different Precursors\nof Carbenes and Nitrenes, Ph.D. Dissertation; The Ohio State University, 2012."},{"key":"2026092310072448400_cit5","doi-asserted-by":"publisher","first-page":"8372","DOI":"10.1021\/acs.jpca.2c04816","article-title":"Photochemistry\nof 1-Phenyl-1-diazopropane and Its Diazirine Isomer: A CASSCF and\nMS-CASPT2 Study","volume":"126","author":"Soto","year":"2022","journal-title":"J. Phys. Chem. 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A"},{"key":"2026092310072448400_cit40","doi-asserted-by":"publisher","first-page":"36","DOI":"10.1071\/ch14097","article-title":"Carbene-Carbene Interconversion on\nthe Singlet Energy\nSurface and Rearrangement to Trifluorobenzocyclobutene, Trifluorostyrene,\nand Trifluoromethylfulvenallenes","volume":"68","author":"Blanch","year":"2015","journal-title":"Aus. J. Chem."},{"key":"2026092310072448400_cit41","doi-asserted-by":"publisher","first-page":"2341","DOI":"10.1021\/jo500044d","article-title":"A Perspective\non Physical Organic Chemistry","volume":"79","author":"Platz","year":"2014","journal-title":"J. Org. Chem."},{"key":"2026092310072448400_cit42","doi-asserted-by":"publisher","first-page":"4286","DOI":"10.1021\/acs.joc.2c02875","article-title":"Ultrafast Photoelimination of Nitrogen\nfrom Upper Excited States of Diazoalkanes and the Fate of Carbenes\nFormed in the Reaction","volume":"88","author":"Brusar","year":"2023","journal-title":"J. Org. Chem."},{"key":"2026092310072448400_cit43","first-page":"9718","article-title":"Photoelimination\nof Nitrogen from Diazoalkanes: Involvement of Higher Excited Singlet\nStates in the Carbene Formation","volume":"142","author":"Pitesa","year":"2020","journal-title":"J. Am. Chem.\nSoc."},{"key":"2026092310072448400_cit44","doi-asserted-by":"publisher","first-page":"11508","DOI":"10.1002\/anie.201804863","article-title":"Carbenes and\nNitrenes: Recent Developments in Fundamental Chemistry","volume":"57","author":"Wentrup","year":"2018","journal-title":"Angew. Chem., Int. Ed."},{"key":"2026092310072448400_cit45","doi-asserted-by":"crossref","first-page":"889","DOI":"10.1002\/poc.1913","article-title":"Effects\nof CF3 groups and charged substituents on singlet carbene stabilities-a\ndensity functional theory study","volume":"24","author":"Sheridan","year":"2011","journal-title":"J. Phys. Org.\nChem."},{"key":"2026092310072448400_cit46","doi-asserted-by":"publisher","first-page":"3041","DOI":"10.1021\/jp810974m","article-title":"Ultrafast Dynamics\nof Isolated Phenylcarbenes Followed\nby Femtosecond Time-Resolved Velocity Map Imaging","volume":"113","author":"Noller","year":"2009","journal-title":"J. Phys. Chem. A"},{"key":"2026092310072448400_cit47","doi-asserted-by":"publisher","first-page":"696","DOI":"10.1098\/rspa.1932.0165","article-title":"Non-adiabatic\ncrossing of energy levels","volume":"137","author":"Zener","year":"1932","journal-title":"Proc. R. Soc. London,\nSer. A"},{"key":"2026092310072448400_cit48","doi-asserted-by":"publisher","first-page":"1","DOI":"10.1146\/annurev.physchem.50.1.1","article-title":"Nonadiabatic\ntransitions: What we learned from old masters and how much we owe\nthem","volume":"50","author":"Nikitin","year":"1999","journal-title":"Annu. Rev. Phys. 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