{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,8,13]],"date-time":"2026-08-13T13:34:26Z","timestamp":1786628066360,"version":"build-2736575974"},"reference-count":45,"publisher":"American Chemical Society (ACS)","issue":"32","license":[{"start":{"date-parts":[[2026,8,1]],"date-time":"2026-08-01T00:00:00Z","timestamp":1785542400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":[],"published-print":{"date-parts":[[2026,8,13]]},"abstract":"<jats:title>Abstract<\/jats:title>\n                  <jats:p>The photochemical and photophysical relaxation pathways of UV filters play a critical role in determining their stability and safety. Here, we present comprehensive gas-phase spectroscopic studies of cinnamate derivatives substituted on the phenyl group with an amino group in the para (M4AC), meta (M3AC), and ortho (M2AC) positions, while the influence of increasing the electron-donating character of the substituent has been investigated by studies on the para-dimethylamino derivative (MeM4AC). Using Resonance Enhanced Multiphoton Ionization (REMPI), UV\u2013UV depletion, pump\u2013probe ion yield measurements, and photoelectron velocity-map imaging (VMI), complemented by electronic structure calculations, we characterize their electronically excited-state structure and dynamics. Compared to previously studied hydroxy- and methoxy-substituted cinnamates, all four derivatives exhibit substantial changes in electronic structure and excited-state behavior. Amino substitution is found to lead to pronounced red shifts of the S1 absorption band and to modify the ordering of the low-lying excited states. Time-resolved measurements show nanosecond excited-state lifetimes that are dominated by radiative and nonradiative relaxation from the S1 state to the ground state, while population transfer to long-lived 1n\u03c0* states -that was previously shown to promote intersystem crossing to the triplet manifold in hydroxy- and methoxy-substituted cinnamates- is strongly suppressed. These results demonstrate that amino substitution has a profound influence on the properties of cinnamate-based UV filters, providing a new molecular design approach to improve UV-absorbing molecular materials.<\/jats:p>","DOI":"10.1021\/acs.jpca.6c04208","type":"journal-article","created":{"date-parts":[[2026,8,4]],"date-time":"2026-08-04T14:05:21Z","timestamp":1785852321000},"page":"6409-6421","source":"Crossref","is-referenced-by-count":0,"title":["Jet-Cooled Spectroscopy\nof Amino-Substituted Cinnamates"],"prefix":"10.1021","volume":"130","author":[{"given":"Hugo","family":"Maurer","sequence":"first","affiliation":[{"name":"University of Amsterdam , , Science Park 904 , ,","place":["Amsterdam, The Netherlands, 1098 XH"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-1265-8016","authenticated-orcid":true,"given":"Wybren Jan","family":"Buma","sequence":"additional","affiliation":[{"name":"University of Amsterdam , , Science Park 904 , ,","place":["Amsterdam, The Netherlands, 1098 XH"]},{"name":"Radboud University, Institute for Molecules and Materials, FELIX Laboratory , Toernooiveld 7c , ,","place":["Nijmegen, The Netherlands, 6525 ED"]}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"316","published-online":{"date-parts":[[2026,8,1]]},"reference":[{"key":"2026081308271353700_cit1","doi-asserted-by":"publisher","DOI":"10.1088\/1748-9326\/8\/2\/024024","article-title":"Quantifying the consensus on anthropogenic\nglobal warming in the\nscientific literature","volume":"8","author":"Cook","year":"2013","journal-title":"Environ. 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Dermatol."},{"key":"2026081308271353700_cit15","unstructured":"U.S. Food and Drug Administration FDA Encourages\nDevelopment of New,\nReliable Alternatives to Animal Testing in Sunscreen\n          2021\n          https:\/\/www.fda.gov\/news-events\/fda-voices\/fda-encourages-development-new-reliable-alternatives-animal-testing-sunscreen. FDA Voices blog. Accessed: March 02, 2026."},{"key":"2026081308271353700_cit16","doi-asserted-by":"publisher","first-page":"834","DOI":"10.1039\/D0CP04402D","article-title":"Substitution effect on the nonradiative\ndecay and trans\u2192 cis photoisomerization route: a guideline\nto develop efficient cinnamate-based sunscreens","volume":"23","author":"Kinoshita","year":"2021","journal-title":"Phys. Chem. Chem. Phys."},{"key":"2026081308271353700_cit17","doi-asserted-by":"publisher","first-page":"9028","DOI":"10.1021\/acs.jpclett.2c02613","article-title":"Excited-state\nbarrier controls E\u2192 Z photoisomerization in p-hydroxycinnamate\nbiochromophores","volume":"13","author":"Ashworth","year":"2022","journal-title":"J. Phys. Chem. Lett."},{"key":"2026081308271353700_cit18","doi-asserted-by":"publisher","first-page":"497","DOI":"10.1021\/acs.jpca.1c08504","article-title":"Substituent and solvent\neffects on the photoisomerization of cinnamate derivatives: an XMS-CASPT2\nstudy","volume":"126","author":"Nomoto","year":"2022","journal-title":"J. Phys. Chem. A"},{"key":"2026081308271353700_cit19","doi-asserted-by":"publisher","first-page":"7375","DOI":"10.1039\/D4CP04803B","article-title":"Molecular heaters:\na green route to boosting crop yields?","volume":"27","author":"Woolley","year":"2025","journal-title":"Phys.\nChem. Chem. 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Phys."},{"key":"2026081308271353700_cit31","doi-asserted-by":"crossref","unstructured":"Ryazanov, M.\n          \n          Development and\nimplementation of methods for sliced velocity map imaging; Studies\nof overtone-induced dissociation and isomerization dynamics of hydroxymethyl\nradical (CH2OH and CD2OH). Ph.D.\nThesis; University of Southern California, 2012.","DOI":"10.1063\/1.3685899"},{"key":"2026081308271353700_cit32","volume-title":"Python 3 Reference\nManual","author":"Van Rossum","year":"2009"},{"key":"2026081308271353700_cit33","doi-asserted-by":"publisher","first-page":"357","DOI":"10.1038\/s41586-020-2649-2","article-title":"Array programming\nwith NumPy","volume":"585","author":"Harris","year":"2020","journal-title":"Nature"},{"key":"2026081308271353700_cit34","doi-asserted-by":"publisher","first-page":"261","DOI":"10.1038\/s41592-019-0686-2","article-title":"SciPy 1.0: fundamental algorithms for scientific computing\nin Python","volume":"17","author":"Virtanen","year":"2020","journal-title":"Nat. Methods"},{"key":"2026081308271353700_cit35","unstructured":"Hickstein, D. D.; Yurchak, R.; Das, D.; Shih, C.-Y.; Gibson, S. 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ACM"},{"key":"2026081308271353700_cit42","doi-asserted-by":"publisher","first-page":"4393","DOI":"10.1039\/c0cp02221g","article-title":"Spectroscopy\nand dynamics of methyl-4-hydroxycinnamate: the influence of isotopic\nsubstitution and water complexation","volume":"13","author":"Smolarek","year":"2011","journal-title":"Phys. Chem.\nChem. Phys."},{"key":"2026081308271353700_cit43","doi-asserted-by":"publisher","first-page":"5580","DOI":"10.1021\/acs.jpca.0c03646","article-title":"Electronic States and\nNonradiative Decay of Cold Gas-Phase Cinnamic Acid Derivatives Studied\nby Laser Spectroscopy with a Laser-Ablation Technique","volume":"124","author":"Iida","year":"2020","journal-title":"J. Phys. Chem. A"},{"key":"2026081308271353700_cit44","doi-asserted-by":"publisher","first-page":"199","DOI":"10.1021\/cr60240a004","article-title":"The triplet state and molecular electronic\nprocesses\nin organic molecules","volume":"66","author":"Lower","year":"1966","journal-title":"Chem. Rev."},{"key":"2026081308271353700_cit45","doi-asserted-by":"publisher","first-page":"17583","DOI":"10.1039\/C8CP00414E","article-title":"Different photoisomerization\nroutes found in the structural isomers of hydroxy methylcinnamate","volume":"20","author":"Kinoshita","year":"2018","journal-title":"Phys. Chem. Chem. Phys."}],"container-title":["The Journal of Physical\nChemistry A"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/pubs.acs.org\/doi\/pdf\/10.1021\/acs.jpca.6c04208","content-type":"application\/pdf","content-version":"vor","intended-application":"unspecified"},{"URL":"https:\/\/pubs.acs.org\/jpcafh\/article-pdf\/130\/32\/6409\/66352583\/acs.jpca.6c04208.pdf","content-type":"application\/pdf","content-version":"vor","intended-application":"syndication"},{"URL":"https:\/\/pubs.acs.org\/jpcafh\/article-pdf\/130\/32\/6409\/66352583\/acs.jpca.6c04208.pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2026,8,13]],"date-time":"2026-08-13T12:53:46Z","timestamp":1786625626000},"score":1,"resource":{"primary":{"URL":"https:\/\/pubs.acs.org\/jpcafh\/article\/130\/32\/6409\/5238199\/Jet-Cooled-Spectroscopy-of-Amino-Substituted"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2026,8,1]]},"references-count":45,"journal-issue":{"issue":"32","published-online":{"date-parts":[[2026,8,1]]},"published-print":{"date-parts":[[2026,8,13]]}},"URL":"https:\/\/doi.org\/10.1021\/acs.jpca.6c04208","relation":{},"ISSN":["1089-5639","1520-5215"],"issn-type":[{"value":"1089-5639","type":"print"},{"value":"1520-5215","type":"electronic"}],"subject":[],"published":{"date-parts":[[2026,8,1]]}}}