{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,5,9]],"date-time":"2026-05-09T05:51:30Z","timestamp":1778305890614,"version":"3.51.4"},"reference-count":35,"publisher":"MDPI AG","issue":"14","license":[{"start":{"date-parts":[[2025,7,18]],"date-time":"2025-07-18T00:00:00Z","timestamp":1752796800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"Funda\u00e7\u00e3o para a Ci\u00eancia e a Tecnologia FCT\u2014Foundation for Science and Technology","award":["UIDB\/04449\/2020"],"award-info":[{"award-number":["UIDB\/04449\/2020"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Molecules"],"abstract":"<jats:p>1,3-Diphenylisobenzofuran (DPBF) is a widely used fluorescent probe for singlet oxygen (1O2) detection in photodynamic applications. In this work, we present an integrated experimental and computational analysis to describe its spectroscopic, photophysical, and reactive properties in ethanol, DMSO, and DMF. UV-Vis and fluorescence measurements across a wide concentration range show well-resolved S0 \u2192 S1 electronic transition of a \u03c0 \u2192 \u03c0* nature with small red shifts in polar aprotic solvents. Fluorescence lifetimes increase slightly with solvent polarity, showing stabilization of the excited state. The 2D PES and Boltzmann populations analysis indicate two co-existing conformers (Cs and C2), with Cs being slightly more stable at room temperature. TD-DFT calculations have been performed using several density functionals and the 6-311+G(2d,p) basis set to calculate absorption\/emission wavelengths, oscillator strengths, transition dipole moments, and radiative lifetimes. Overall, cam-B3LYP and \u03c9B97X-D provided the best agreement with experiments for the photophysical data across all solvents. The photophysical behavior of DPBF upon interaction with 1O2 can be explained by a small-barrier, two-step reaction pathway that goes through a zwitterionic intermediate, resulting in the formation of 2,5-endoperoxide. This work explains the photophysical properties and reactivity of DPBF, therefore providing a solid basis for future studies involving singlet oxygen.<\/jats:p>","DOI":"10.3390\/molecules30143021","type":"journal-article","created":{"date-parts":[[2025,7,18]],"date-time":"2025-07-18T11:12:34Z","timestamp":1752837154000},"page":"3021","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":8,"title":["Photophysical Properties of 1,3-Diphenylisobenzofuran as a Sensitizer and Its Reaction with O2"],"prefix":"10.3390","volume":"30","author":[{"ORCID":"https:\/\/orcid.org\/0009-0009-8456-1035","authenticated-orcid":false,"given":"\u0218tefan","family":"Stan","sequence":"first","affiliation":[{"name":"Faculty of Physics, Babes-Bolyai University, Str. M. Kog\u0103lniceanu 1, RO-400084 Cluj-Napoca, Romania"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-4419-6431","authenticated-orcid":false,"given":"Jo\u00e3o P. Prates","family":"Ramalho","sequence":"additional","affiliation":[{"name":"Department of Chemistry and Biochemistry, School of Science and Technology, University of \u00c9vora, Rua Rom\u00e3o Ramalho 59, 7000-671 \u00c9vora, Portugal"},{"name":"Hercules Laboratory, University of \u00c9vora, Pal\u00e1cio do Vimioso, Largo Marqu\u00eas de Marialva 8, 7000-809 \u00c9vora, Portugal"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-8682-3929","authenticated-orcid":false,"given":"Alexandru","family":"Holca","sequence":"additional","affiliation":[{"name":"Faculty of Physics, Babes-Bolyai University, Str. M. Kog\u0103lniceanu 1, RO-400084 Cluj-Napoca, Romania"},{"name":"Nanobiophotonics and Laser Microspectroscopy Center, Interdisciplinary Research Institute in Bio-Nano-Sciences, Babes-Bolyai University, T. Laurian 42, RO-400271 Cluj-Napoca, Romania"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-0935-4134","authenticated-orcid":false,"given":"Vasile","family":"Chi\u0219","sequence":"additional","affiliation":[{"name":"Faculty of Physics, Babes-Bolyai University, Str. M. Kog\u0103lniceanu 1, RO-400084 Cluj-Napoca, Romania"}]}],"member":"1968","published-online":{"date-parts":[[2025,7,18]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","unstructured":"Entradas, T., Waldron, S., and Volk, M. (2020). The detection sensitivity of commonly used singlet oxygen probes in aqueous environments. J. Photochem. Photobiol. B Biol., 204.","DOI":"10.1016\/j.jphotobiol.2020.111787"},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"395","DOI":"10.1163\/156856793X00181","article-title":"On the use of 1,3-diphenylisobenzofuran (DPBF). Reactions with carbon and oxygen centered radicals in model and natural systems","volume":"19","author":"Carloni","year":"1993","journal-title":"Res. Chem. 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