{
  "abstract": "Azulene, a non-benzenoid aromatic system, exhibits a unique electronic structure that gives rise to unconventional excited-state dynamics. Here, we investigate a series of halogenated and carbonylated azulenes using ultrafast spectroscopy and quantum chemical calculations. Despite incorporating substituents that are known to enhance intersystem crossing (ISC), halogenated/carbonylated azulenes exclusively display singlet excited-state dynamics. Femtosecond and nanosecond transient absorption measurements reveal rapid internal conversion without any detectable triplet population. Computational analysis using the Marcus formalism confirms that, although spin–orbit coupling increases upon bromination/carbonylation, ISC remains orders of magnitude too slow to compete with fast internal conversion. These findings highlight the intrinsic resistance of azulene derivatives to triplet-state formation, challenging established strategies for promoting ISC and offering new insights into substitution-dependent excited-state pathways in non-benzenoid aromatics.",
  "abstract_shown": true,
  "affiliations": [
    "School of Chemistry, Indian Institute of Science Education and Research Thiruvananthapuram (IISER TVM) Maruthamala P.O., Vithura Thiruvananthapuram 695551 Kerala India",
    "Donostia International Physics Center (DIPC) 20018 Donostia Euskadi Spain",
    "IKERBASQUE− Basque Foundation for Science 48009 Bilbao Euskadi Spain",
    "Department of Chemistry - Ångström Laboratory, Uppsala University Box 523 Uppsala 751 20 Sweden"
  ],
  "article_type": "research article",
  "arxiv": null,
  "author_total": 9,
  "authors": [
    {
      "affs": [
        0
      ],
      "name": "Kavya Vinod",
      "orcid": "0000-0002-7537-0335"
    },
    {
      "affs": [
        1,
        2
      ],
      "name": "Claire Tonnelé",
      "orcid": "0000-0003-0791-8239"
    },
    {
      "affs": [
        3
      ],
      "name": "Anup Rana"
    },
    {
      "affs": [
        0
      ],
      "name": "T. Amalnadh"
    },
    {
      "affs": [
        0
      ],
      "name": "P. E. Swathi Krishna"
    },
    {
      "affs": [
        1
      ],
      "name": "Juan Carlos Roldao"
    },
    {
      "affs": [
        3
      ],
      "name": "Henrik Ottosson",
      "orcid": "0000-0001-8076-1165"
    },
    {
      "affs": [
        1,
        2
      ],
      "name": "David Casanova",
      "orcid": "0000-0002-8893-7089"
    },
    {
      "affs": [
        0
      ],
      "name": "Mahesh Hariharan",
      "orcid": "0000-0002-3237-6235"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/5ch7kfz6x1mrr.bib",
  "cited_by": 0,
  "doi": "10.1039/d6sc00694a",
  "fulltext_url": "https://pmc.ncbi.nlm.nih.gov/articles/PMC13576160/",
  "id": "5ch7kfz6x1mrr",
  "issns": [
    "2041-6520",
    "2041-6539"
  ],
  "landing_url": "https://doi.org/10.1039/d6sc00694a",
  "language": "en",
  "licence": "CC-BY-NC-3.0",
  "licence_label": "CC BY-NC 3.0",
  "licence_source": "article",
  "licence_url": "https://creativecommons.org/licenses/by-nc/3.0/",
  "metadata_licence": null,
  "native_subjects": [
    [
      "heading",
      "Chemistry"
    ],
    [
      "openalex",
      "1606|Photochemistry and Electron Transfer Studies"
    ]
  ],
  "openalex": "W7211893106",
  "pdf_url": "https://pubs.rsc.org/sc/article-pdf/doi/10.1039/D6SC00694A/13759693/d6sc00694a.pdf",
  "pmcid": "PMC13576160",
  "pmid": "42746194",
  "published": "2026-09-07",
  "publisher": "Royal Society of Chemistry",
  "ris": "https://research.draconitic.com/paper/5ch7kfz6x1mrr.ris",
  "sources": [
    {
      "first_seen": "2026-11-07T12:23:29Z",
      "native_id": "PMC13576160",
      "source": "pmc",
      "url": "https://doi.org/10.1039/d6sc00694a"
    }
  ],
  "subjects": [
    {
      "field": "chemistry",
      "origin": "openalex:1606|Photochemistry and Electron Transfer Studies",
      "subfield": "physical"
    }
  ],
  "title": "Azulene as an anomaly in triplet-state engineering via bromination and/or carbonylation: internal conversion overrides intersystem crossing",
  "title_text": "Azulene as an anomaly in triplet-state engineering via bromination and/or carbonylation: internal conversion overrides intersystem crossing",
  "type": "peer-reviewed",
  "updated_at": "2026-11-08T12:20:58Z",
  "url": "https://research.draconitic.com/paper/5ch7kfz6x1mrr",
  "venue": "Chemical Science",
  "versions": []
}