{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,22]],"date-time":"2026-09-22T13:05:52Z","timestamp":1790082352216,"version":"4.0.1"},"reference-count":38,"publisher":"AIP Publishing","issue":"12","funder":[{"name":"Excellent Youth Foundation of Henan Scientific Committee","award":["252300421056"],"award-info":[{"award-number":["252300421056"]}]},{"DOI":"10.13039\/501100001809","name":"National Natural Science Foundation of China","doi-asserted-by":"publisher","award":["11974103"],"award-info":[{"award-number":["11974103"]}],"id":[{"id":"10.13039\/501100001809","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100001809","name":"National Natural Science Foundation of China","doi-asserted-by":"publisher","award":["12574286"],"award-info":[{"award-number":["12574286"]}],"id":[{"id":"10.13039\/501100001809","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100001809","name":"National Natural Science Foundation of China","doi-asserted-by":"publisher","award":["12074104"],"award-info":[{"award-number":["12074104"]}],"id":[{"id":"10.13039\/501100001809","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100001809","name":"National Natural Science Foundation of China","doi-asserted-by":"publisher","award":["12474257"],"award-info":[{"award-number":["12474257"]}],"id":[{"id":"10.13039\/501100001809","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100006407","name":"Natural Science Foundation of Henan Province","doi-asserted-by":"publisher","award":["262300421061"],"award-info":[{"award-number":["262300421061"]}],"id":[{"id":"10.13039\/501100006407","id-type":"DOI","asserted-by":"publisher"}]},{"name":"Henan Province University Science and Technology Innovation Talents Support Plan","award":["21HASTIT019"],"award-info":[{"award-number":["21HASTIT019"]}]},{"name":"Henan Province University Science and Technology Innovation Talents Support Plan","award":["24HASTIT030"],"award-info":[{"award-number":["24HASTIT030"]}]},{"name":"Henan Province Science and Technology Research and Development Plan Joint Fund","award":["225200810039"],"award-info":[{"award-number":["225200810039"]}]}],"content-domain":{"domain":["pubs.aip.org"],"crossmark-restriction":true},"short-container-title":[],"published-print":{"date-parts":[[2026,9,28]]},"abstract":"<jats:p>Photoinduced [6\u03c0]-electrocyclization of triphenylamine provides an efficient route to the construction of carbazole frameworks. In this work, 4-(diphenylamino)phenol (TPA-OH) was selected as a model compound to examine how hydroxyl substitution breaks the symmetry of triphenylamine and differentiates its photocyclization pathways. Transient absorption spectroscopy revealed that the singlet excited-state absorption of 1TPA-OH at 627\u00a0nm decays within 1.6\u00a0ns, accompanied by the emergence of the triplet excited-state absorption of 3TPA-OH at 508\u00a0nm, which subsequently decays with a lifetime of 45.7\u00a0ns. Thereafter, a positive absorption signal appears at 441\u00a0nm, corresponding to the triplet cyclization intermediate 3DHC0-OH. The long-lived absorption band near 608\u00a0nm is attributed to overlapping contributions from 1DHC0-OH and subsequent product-related species. Intrinsic reaction coordinate and Mayer bond-order analyses confirm that ring closure is governed by intramolecular C\u2013C bond formation. Hydroxyl substitution changes the equivalence of the ring-closing sites, allowing ring closure either between the two unsubstituted phenyl rings (EXO cyclization) or through involvement of the hydroxyl-substituted phenyl ring (ENDO cyclization). On both the potential-energy and free-energy surfaces, the EXO pathway is favored over the ENDO pathway, exhibiting a lower potential-energy barrier (4.5 vs 26.5\u00a0kcal mol\u22121), a substantially lower Gibbs free-energy barrier (28.4 vs 112.1 kJ mol\u22121), and a more stable cyclized product (\u221242.6 vs \u22124.5 kJ mol\u22121). Although hydroxyl substitution does not alter the dominance of the EXO channel, it provides mechanistic insights and suggests a potential avenue for the targeted synthesis of carbazoles via the ENDO pathway.<\/jats:p>","DOI":"10.1063\/5.0348696","type":"journal-article","created":{"date-parts":[[2026,9,22]],"date-time":"2026-09-22T12:13:56Z","timestamp":1790079236000},"update-policy":"https:\/\/doi.org\/10.1063\/aip-crossmark-policy-page","source":"Crossref","is-referenced-by-count":0,"title":["Hydroxyl-directed differentiation of photocyclization pathways in triphenylamine monitored by transient absorption spectroscopy"],"prefix":"10.1063","volume":"165","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-1770-4034","authenticated-orcid":false,"given":"Yonggang","family":"Yang","sequence":"first","affiliation":[{"name":"Henan Key Laboratory of Infrared Materials and Spectrum Measures and Applications, Henan Province Engineering Research Center of Optoelectronic Technology and Advanced Manufacturing, School of Physics, Henan Normal University 1 , Xinxiang 453007,","place":["China"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0009-0008-2689-2920","authenticated-orcid":false,"given":"Xuchao","family":"Cui","sequence":"additional","affiliation":[{"name":"Henan Key Laboratory of Infrared Materials and Spectrum Measures and Applications, Henan Province Engineering Research Center of Optoelectronic Technology and Advanced Manufacturing, School of Physics, Henan Normal University 1 , Xinxiang 453007,","place":["China"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-9462-4102","authenticated-orcid":false,"given":"Yang","family":"Liu","sequence":"additional","affiliation":[{"name":"Henan Key Laboratory of Infrared Materials and Spectrum Measures and Applications, Henan Province Engineering Research Center of Optoelectronic Technology and Advanced Manufacturing, School of Physics, Henan Normal University 1 , Xinxiang 453007,","place":["China"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Tiantian","family":"Guan","sequence":"additional","affiliation":[{"name":"Henan Key Laboratory of Infrared Materials and Spectrum Measures and Applications, Henan Province Engineering Research Center of Optoelectronic Technology and Advanced Manufacturing, School of Physics, Henan Normal University 1 , Xinxiang 453007,","place":["China"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0009-0006-7154-1201","authenticated-orcid":false,"given":"Wanzhen","family":"Zong","sequence":"additional","affiliation":[{"name":"Henan Key Laboratory of Infrared Materials and Spectrum Measures and Applications, Henan Province Engineering Research Center of Optoelectronic Technology and Advanced Manufacturing, School of Physics, Henan Normal University 1 , Xinxiang 453007,","place":["China"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0009-0005-7743-8312","authenticated-orcid":false,"given":"Chenhao","family":"Zheng","sequence":"additional","affiliation":[{"name":"Henan Key Laboratory of Infrared Materials and Spectrum Measures and Applications, Henan Province Engineering Research Center of Optoelectronic Technology and Advanced Manufacturing, School of Physics, Henan Normal University 1 , Xinxiang 453007,","place":["China"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-3665-6111","authenticated-orcid":false,"given":"Chaochao","family":"Qin","sequence":"additional","affiliation":[{"name":"Henan Key Laboratory of Infrared Materials and Spectrum Measures and Applications, Henan Province Engineering Research Center of Optoelectronic Technology and Advanced Manufacturing, School of Physics, Henan Normal University 1 , Xinxiang 453007,","place":["China"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-1896-8864","authenticated-orcid":false,"given":"Yufang","family":"Liu","sequence":"additional","affiliation":[{"name":"Henan Key Laboratory of Infrared Materials and Spectrum Measures and Applications, Henan Province Engineering Research Center of Optoelectronic Technology and Advanced Manufacturing, School of Physics, Henan Normal University 1 , Xinxiang 453007,","place":["China"]},{"name":"Institute of Physics, Henan Academy of Sciences 2 , Zhengzhou 450008,","place":["China"]}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"317","published-online":{"date-parts":[[2026,9,22]]},"reference":[{"issue":"22","key":"2026092208135069900_c1","doi-asserted-by":"publisher","first-page":"6754","DOI":"10.3390\/ma14226754","article-title":"2,7(3,6)-diaryl(arylamino)-substituted carbazoles as components of OLEDs: A review of the last decade","volume":"14","year":"2021","journal-title":"Materials"},{"issue":"19","key":"2026092208135069900_c2","doi-asserted-by":"publisher","first-page":"4304","DOI":"10.1039\/d3qm00399j","article-title":"A review of fused-ring carbazole derivatives as emitter and\/or host materials in organic light emitting diode (OLED) applications","volume":"7","year":"2023","journal-title":"Mater. Chem. Front."},{"issue":"10","key":"2026092208135069900_c3","doi-asserted-by":"publisher","first-page":"2227","DOI":"10.3390\/polym12102227","article-title":"Polycarbazole and its derivatives: Synthesis and applications. A review of the last 10 years","volume":"12","year":"2020","journal-title":"Polymers"},{"issue":"9","key":"2026092208135069900_c4","doi-asserted-by":"publisher","first-page":"1297","DOI":"10.1016\/s0079-6700(03)00036-4","article-title":"Carbazole-containing polymers: Synthesis, properties and applications","volume":"28","year":"2003","journal-title":"Prog. Polym. Sci."},{"issue":"10","key":"2026092208135069900_c5","doi-asserted-by":"publisher","first-page":"e202200059","DOI":"10.1002\/cptc.202200059","article-title":"Recent advances in the design of multi-substituted carbazoles for optoelectronics: Synthesis and structure\u2013property outlook","volume":"6","year":"2022","journal-title":"ChemPhotoChem"},{"issue":"23","key":"2026092208135069900_c6","doi-asserted-by":"publisher","first-page":"8804","DOI":"10.1021\/jacs.1c03240","article-title":"[4]cyclo-N-alkyl-2,7-carbazoles: Influence of the alkyl chain length on the structural, electronic, and charge transport properties","volume":"143","year":"2021","journal-title":"J.\u00a0Am. Chem. Soc."},{"issue":"6","key":"2026092208135069900_c7","doi-asserted-by":"publisher","first-page":"3193","DOI":"10.1021\/cr200447s","article-title":"Occurrence, biogenesis, and synthesis of biologically active carbazole alkaloids","volume":"112","year":"2012","journal-title":"Chem. Rev."},{"issue":"45","key":"2026092208135069900_c8","doi-asserted-by":"publisher","first-page":"8956","DOI":"10.1039\/d3ob01605f","article-title":"Trends in carbazole synthesis-an update (2013-2023)","volume":"21","year":"2023","journal-title":"Org. Biomol. Chem."},{"issue":"8","key":"2026092208135069900_c9","doi-asserted-by":"publisher","first-page":"e202303229","DOI":"10.1002\/chem.202303229","article-title":"Preparation of carbazoles involving 6\u03c0-electrocyclization, photoredox-electrochemical-and thermal cyclization reactions: Mechanistic insights","volume":"30","year":"2024","journal-title":"Chem.-Eur. J."},{"issue":"12","key":"2026092208135069900_c10","doi-asserted-by":"publisher","first-page":"2269","DOI":"10.1007\/s43630-024-00661-z","article-title":"On the application of nanosecond laser flash photolysis to the investigation of the photoreactivity of di and triarylamines","volume":"23","year":"2024","journal-title":"Photochem. Photobiol. Sci."},{"issue":"12","key":"2026092208135069900_c11","doi-asserted-by":"publisher","first-page":"1881","DOI":"10.1021\/ja00895a048","article-title":"Photo-conversion of diphenylamines to carbazoles, and accompanying transient species","volume":"85","year":"1963","journal-title":"J.\u00a0Am. Chem. Soc."},{"key":"2026092208135069900_c12","doi-asserted-by":"publisher","first-page":"1050","DOI":"10.1038\/2231050a0","article-title":"Triplet state of triphenylamine","volume":"223","year":"1969","journal-title":"Nature"},{"issue":"1","key":"2026092208135069900_c13","doi-asserted-by":"publisher","first-page":"70","DOI":"10.1039\/b006031n","article-title":"Photocyclization of triphenylamine: An investigation through time-resolved photoacoustic calorimetry","volume":"3","year":"2001","journal-title":"Phys. Chem. Chem. Phys."},{"issue":"6","key":"2026092208135069900_c14","doi-asserted-by":"publisher","first-page":"1245","DOI":"10.1021\/jp076788q","article-title":"Photoinduced oxygen uptake of diphenylamines in solution and their ring closure revisited","volume":"112","year":"2008","journal-title":"J.\u00a0Phys. Chem. A"},{"issue":"18","key":"2026092208135069900_c15","doi-asserted-by":"publisher","first-page":"2932","DOI":"10.1016\/j.tetlet.2014.03.086","article-title":"(Co)oxidation\/cyclization processes upon irradiation of triphenylamine","volume":"55","year":"2014","journal-title":"Tetrahedron Lett."},{"issue":"36","key":"2026092208135069900_c16","doi-asserted-by":"publisher","first-page":"16581","DOI":"10.1039\/d1nj03101e","article-title":"Photochemistry of triphenylamine (TPA) in homogeneous solution and the role of transient N-phenyl-4a,4b-dihydrocarbazole. A steady-state and time-resolved investigation","volume":"45","year":"2021","journal-title":"New J. Chem."},{"issue":"20","key":"2026092208135069900_c17","doi-asserted-by":"publisher","first-page":"13439","DOI":"10.1021\/acs.joc.2c00756","article-title":"Photoinduced [6\u03c0]-electrocyclic reaction of mono-di-and trisubstituted triphenylamines in acetonitrile. A steady-state investigation","volume":"87","year":"2022","journal-title":"J.\u00a0Org. Chem."},{"issue":"7","key":"2026092208135069900_c18","doi-asserted-by":"publisher","first-page":"4405","DOI":"10.1021\/acs.joc.2c03022","article-title":"Solvent effects on the photoinduced [6\u03c0]-electrocyclization reactions of mono-di-and trisubstituted arylamines: Photophysical, preparative photochemistry, and mechanistic investigations","volume":"88","year":"2023","journal-title":"J.\u00a0Org. Chem."},{"issue":"40","key":"2026092208135069900_c19","doi-asserted-by":"publisher","first-page":"9381","DOI":"10.1021\/acs.jpclett.2c02519","article-title":"Transient absorption spectroscopy of a carbazole-based room-temperature phosphorescent molecule: Real-time monitoring of singlet\u2013triplet transitions","volume":"13","year":"2022","journal-title":"J.\u00a0Phys. Chem. Lett."},{"key":"2026092208135069900_c20","doi-asserted-by":"publisher","first-page":"121121","DOI":"10.1016\/j.jlumin.2025.121121","article-title":"Direct observation of triplet\u2013triplet intermediates in the photocyclization reaction of triphenylamine using transient absorption spectroscopy","volume":"280","year":"2025","journal-title":"J.\u00a0Lumin."},{"key":"2026092208135069900_c21","volume-title":"Gaussian 16, Revision C.01","year":"2016"},{"issue":"13","key":"2026092208135069900_c22","doi-asserted-by":"publisher","first-page":"6158","DOI":"10.1063\/1.478522","article-title":"Toward reliable density functional methods without adjustable parameters: The PBE0 model","volume":"110","year":"1999","journal-title":"J.\u00a0Chem. Phys."},{"issue":"18","key":"2026092208135069900_c23","doi-asserted-by":"publisher","first-page":"3297","DOI":"10.1039\/b508541a","article-title":"Balanced basis sets of split valence, triple zeta valence and quadruple zeta valence quality for H to Rn: Design and assessment of accuracy","volume":"7","year":"2005","journal-title":"Phys. Chem. Chem. Phys."},{"key":"2026092208135069900_c24","doi-asserted-by":"crossref","first-page":"155","DOI":"10.1142\/2914","article-title":"Time-dependent density functional response theory for molecules","volume-title":"Recent Advances in Density Functional Methods, Part I","author":"Chong","year":"1995"},{"issue":"4\u20135","key":"2026092208135069900_c25","doi-asserted-by":"publisher","first-page":"454","DOI":"10.1016\/0009-2614(96)00440-x","article-title":"Treatment of electronic excitations within the adiabatic approximation of time dependent density functional theory","volume":"256","year":"1996","journal-title":"Chem. Phys. Lett."},{"issue":"8","key":"2026092208135069900_c26","doi-asserted-by":"publisher","first-page":"3032","DOI":"10.1063\/1.474659","article-title":"A new integral equation formalism for the polarizable continuum model: Theoretical background and applications to isotropic and anisotropic dielectrics","volume":"107","year":"1997","journal-title":"J.\u00a0Chem. Phys."},{"issue":"23","key":"2026092208135069900_c27","doi-asserted-by":"publisher","first-page":"4161","DOI":"10.1021\/j100717a029","article-title":"Formulation of the reaction coordinate","volume":"74","year":"1970","journal-title":"J.\u00a0Phys. Chem."},{"issue":"12","key":"2026092208135069900_c28","doi-asserted-by":"publisher","first-page":"363","DOI":"10.1021\/ar00072a001","article-title":"The path of chemical reactions\u2014The IRC approach","volume":"14","year":"1981","journal-title":"Acc. Chem. Res."},{"key":"2026092208135069900_c29","doi-asserted-by":"publisher","first-page":"4775","DOI":"10.1063\/1.1558471","article-title":"Natural transition orbitals","volume":"118","year":"2003","journal-title":"J.\u00a0Chem. Phys."},{"issue":"5","key":"2026092208135069900_c30","doi-asserted-by":"publisher","first-page":"580","DOI":"10.1002\/jcc.22885","article-title":"Multiwfn: A multifunctional wavefunction analyzer","volume":"33","year":"2012","journal-title":"J.\u00a0Comput. Chem."},{"key":"2026092208135069900_c31","doi-asserted-by":"publisher","first-page":"2095","DOI":"10.1039\/b102094n","article-title":"The Mayer bond order as a tool in inorganic chemistry","volume":"30","year":"2001","journal-title":"J.\u00a0Chem. Soc., Dalton Trans."},{"key":"2026092208135069900_c32","doi-asserted-by":"publisher","first-page":"113249","DOI":"10.1016\/j.comptc.2021.113249","article-title":"Shermo: A general code for calculating molecular thermochemistry properties","volume":"1200","year":"2021","journal-title":"Comput. Theor. Chem."},{"issue":"1","key":"2026092208135069900_c33","doi-asserted-by":"publisher","first-page":"73","DOI":"10.1002\/wcms.81","article-title":"The ORCA program system","volume":"2","year":"2012","journal-title":"Wiley Interdiscip. Rev.: Comput. Mol. Sci."},{"issue":"1","key":"2026092208135069900_c34","doi-asserted-by":"publisher","first-page":"e1327","DOI":"10.1002\/wcms.1327","article-title":"Software update: The ORCA program system, version 4.0","volume":"8","year":"2018","journal-title":"Wiley Interdiscip. Rev.: Comput. Mol. Sci."},{"issue":"5","key":"2026092208135069900_c35","doi-asserted-by":"publisher","first-page":"e1606","DOI":"10.1002\/wcms.1606","article-title":"Software update: The ORCA program system\u2014Version 5.0","volume":"12","year":"2022","journal-title":"Wiley Interdiscip. Rev.: Comput. Mol. Sci."},{"issue":"2","key":"2026092208135069900_c36","doi-asserted-by":"publisher","first-page":"e70019","DOI":"10.1002\/wcms.70019","article-title":"Software update: The ORCA program system\u2014version 6.0","volume":"15","year":"2025","journal-title":"Wiley Interdiscip. Rev.: Comput. Mol. Sci."},{"issue":"4","key":"2026092208135069900_c37","doi-asserted-by":"publisher","first-page":"536","DOI":"10.1016\/0009-2614(72)80258-6","article-title":"The light-induced conversion of triphenylamine to the excited triplet state of 11,12-dihydrocarbazole","volume":"14","year":"1972","journal-title":"Chem. Phys. Lett."},{"issue":"15","key":"2026092208135069900_c38","doi-asserted-by":"publisher","first-page":"6975","DOI":"10.1021\/acs.chemrev.7b00617","article-title":"Spin-vibronic mechanism for intersystem crossing","volume":"118","year":"2018","journal-title":"Chem. Rev."}],"container-title":["The Journal of Chemical Physics"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/pubs.aip.org\/aip\/jcp\/article-pdf\/doi\/10.1063\/5.0348696\/21146498\/124201_1_5.0348696.pdf","content-type":"application\/pdf","content-version":"vor","intended-application":"syndication"},{"URL":"https:\/\/pubs.aip.org\/aip\/jcp\/article-pdf\/doi\/10.1063\/5.0348696\/21146498\/124201_1_5.0348696.pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2026,9,22]],"date-time":"2026-09-22T12:13:58Z","timestamp":1790079238000},"score":1,"resource":{"primary":{"URL":"https:\/\/pubs.aip.org\/jcp\/article\/165\/12\/124201\/3404923\/Hydroxyl-directed-differentiation-of"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2026,9,22]]},"references-count":38,"journal-issue":{"issue":"12","published-print":{"date-parts":[[2026,9,28]]}},"URL":"https:\/\/doi.org\/10.1063\/5.0348696","relation":{},"ISSN":["0021-9606","1089-7690"],"issn-type":[{"value":"0021-9606","type":"print"},{"value":"1089-7690","type":"electronic"}],"subject":[],"published-other":{"date-parts":[[2026,9,28]]},"published":{"date-parts":[[2026,9,22]]},"article-number":"124201"}}