{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,9,30]],"date-time":"2025-09-30T04:40:38Z","timestamp":1759207238845,"version":"3.44.0"},"reference-count":46,"publisher":"MDPI AG","issue":"19","license":[{"start":{"date-parts":[[2025,9,27]],"date-time":"2025-09-27T00:00:00Z","timestamp":1758931200000},"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","award":["UIDB\/00100\/2020","UIDB\/04565\/2020","LA\/P\/0056\/2020"],"award-info":[{"award-number":["UIDB\/00100\/2020","UIDB\/04565\/2020","LA\/P\/0056\/2020"]}]}],"content-domain":{"domain":["www.mdpi.com"],"crossmark-restriction":true},"short-container-title":["Molecules"],"abstract":"<jats:p>Two fluorescent ureido-dihomooxacalix[4]arene derivatives containing naphthyl residues at the lower rim (1 and 2) were studied for the detection of nitroaromatic compounds (NACs) in solution and in vapour phases. Their affinity in solution was determined by UV-Vis absorption, fluorescence and NMR spectroscopy. For NAC vapour sensing, calixarenes were dispersed in a polytetrafluoroethylene (PTFE) matrix. Four new solvated crystals of dihomooxacalix[4]arene 2 were obtained and the solvent\u2019s influence on its structural characteristics was investigated. The solvent-dependent structural variations observed in the crystal structures highlight the intrinsic flexibility of the calixarene framework. Such conformational adaptability, evident in the disruption and reorganization of hydrogen bonding and \u03c0\u2013\u03c0 interactions, is directly relevant to nitroaromatic sensing, where a rapid and reversible host response is crucial for effective detection. Theoretical calculations were also performed to provide further insights on the binding process. The corrected Stern\u2013Volmer constants (KSV) obtained showed that both receptors present selectivity for TNP and follow the same quenching order (TNP &gt; NT &gt; NB &gt; DNT &gt; TNT &gt; DNB). Factors other than electron density distribution should dominate the quenching extent and therefore the values of the SV constants, which will be greatly overestimated if no correction to the inner filter effect is applied. Detection of NB and NT and vapours by both calixarenes produced a complete, very fast (2 to 5 s), and reversible quenching, indicating the potential use of this porous PTFE\u2013calixarene matrix for the sensing of volatile NACs.<\/jats:p>","DOI":"10.3390\/molecules30193901","type":"journal-article","created":{"date-parts":[[2025,9,29]],"date-time":"2025-09-29T12:59:46Z","timestamp":1759150786000},"page":"3901","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Fluorescent Dihomooxacalix[4]arenes for the Detection of Nitroaromatic Compounds in Solution and in the Vapour Phase: Structural and Supramolecular Insights"],"prefix":"10.3390","volume":"30","author":[{"given":"Beatriz V.","family":"Gil","sequence":"first","affiliation":[{"name":"Centro de Qu\u00edmica Estrutural, Institute of Molecular Sciences, Faculdade de Ci\u00eancias, Universidade de Lisboa, Edif\u00edcio C8, 1749-016 Lisboa, Portugal"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-8727-7077","authenticated-orcid":false,"given":"Alexandre S.","family":"Miranda","sequence":"additional","affiliation":[{"name":"Centro de Qu\u00edmica Estrutural, Institute of Molecular Sciences, Faculdade de Ci\u00eancias, Universidade de Lisboa, Edif\u00edcio C8, 1749-016 Lisboa, Portugal"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-7297-5139","authenticated-orcid":false,"given":"Paula M.","family":"Marcos","sequence":"additional","affiliation":[{"name":"Centro de Qu\u00edmica Estrutural, Institute of Molecular Sciences, Faculdade de Ci\u00eancias, Universidade de Lisboa, Edif\u00edcio C8, 1749-016 Lisboa, Portugal"},{"name":"Faculdade de Farm\u00e1cia, Universidade de Lisboa, Av. Prof. Gama Pinto, 1649-003 Lisboa, Portugal"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-5535-2500","authenticated-orcid":false,"given":"Jos\u00e9 R.","family":"Ascenso","sequence":"additional","affiliation":[{"name":"Centro de Qu\u00edmica Estrutural, Institute of Molecular Sciences, Instituto Superior T\u00e9cnico, Universidade de Lisboa, Complexo I, Av. Rovisco Pais, 1049-001 Lisboa, Portugal"}]},{"given":"Tiago","family":"Palmeira","sequence":"additional","affiliation":[{"name":"Centro de Qu\u00edmica Estrutural, Institute of Molecular Sciences, Instituto Superior T\u00e9cnico, Universidade de Lisboa, Complexo I, Av. Rovisco Pais, 1049-001 Lisboa, Portugal"},{"name":"IBB-Institute for Bioengineering and Biosciences, Instituto Superior T\u00e9cnico, Universidade de Lisboa, 1049-001 Lisboa, Portugal"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-2946-1498","authenticated-orcid":false,"given":"M\u00e1rio N.","family":"Berberan-Santos","sequence":"additional","affiliation":[{"name":"IBB-Institute for Bioengineering and Biosciences, Instituto Superior T\u00e9cnico, Universidade de Lisboa, 1049-001 Lisboa, Portugal"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-2433-8773","authenticated-orcid":false,"given":"Rachel","family":"Schurhammer","sequence":"additional","affiliation":[{"name":"Laboratoire de Mod\u00e9lisation et Simulations Mol\u00e9culaires, Universit\u00e9 de Strasbourg, UMR 7140, F-67000 Strasbourg, France"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-1271-5719","authenticated-orcid":false,"given":"Neal","family":"Hickey","sequence":"additional","affiliation":[{"name":"Centre of Excellence in Biocrystallography, Department of Chemical and Pharmaceutical Sciences, University of Trieste, via L. Giorgieri 1, 34127 Trieste, Italy"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-2182-6074","authenticated-orcid":false,"given":"Siddharth","family":"Joshi","sequence":"additional","affiliation":[{"name":"Centre of Excellence in Biocrystallography, Department of Chemical and Pharmaceutical Sciences, University of Trieste, via L. Giorgieri 1, 34127 Trieste, Italy"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-0711-5113","authenticated-orcid":false,"given":"Silvano","family":"Geremia","sequence":"additional","affiliation":[{"name":"Centre of Excellence in Biocrystallography, Department of Chemical and Pharmaceutical Sciences, University of Trieste, via L. Giorgieri 1, 34127 Trieste, Italy"}]}],"member":"1968","published-online":{"date-parts":[[2025,9,27]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"8019","DOI":"10.1039\/C5CS00496A","article-title":"Fluorescence based explosive detection: From mechanisms to sensory materials","volume":"44","author":"Sun","year":"2015","journal-title":"Chem. Soc. Rev."},{"key":"ref_2","doi-asserted-by":"crossref","unstructured":"Pedras, B. (2019). Explosive detection: From sensing to response. Fluorescence in Industry, Springer.","DOI":"10.1007\/978-3-030-20033-6"},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"112685","DOI":"10.1016\/j.jenvman.2021.112685","article-title":"Environmental occurrence, toxicity concerns, and remediation of recalcitrant nitroaromatic compounds","volume":"291","author":"Bilal","year":"2021","journal-title":"J. Environ. 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