{
  "abstract": "The photochemistry of 2-benzo[b]thienyl diazomethane (1) and 3-benzo[b]thienyl diazomethane (3), matrix-isolated in Ar or N2 at 10 K, was studied by IR, UV/vis, and EPR spectroscopy. Although the corresponding 2- and 3-benzo[b]thienyl carbenes (16, 17) were not observed, several interesting rearrangement products (C9H6S isomers) were characterized by IR and UV/vis spectroscopy. 2-Benzo[b]thienyl diazomethane (1) undergoes ring expansion (λ > 534 nm) to form the strained allene 5,6-benzo-1-thiacyclohexa-2,3-diene (8). 3-Benzo[b]thienyl diazomethane (3) undergoes cyclization (λ > 472 nm) to form 2-thia-3,4-benzobicyclo[3.1.0]-hexa-3,5-diene (13). Irradiation of 13 (λ = 340 nm ± 10 nm) results in ring-opening to form a dark purple quinoid thione intermediate (19), which reverts to cyclopropene 13 upon visible light irradiation (λ = 540 nm ± 10 nm). Structural assignments were confirmed by isotope labeling and comparison of experimental spectra with those predicted using anharmonic density functional theory calculations.",
  "abstract_shown": true,
  "affiliations": [
    "Department of Chemistry, University of Wisconsin-Madison, 1101 University Avenue, Madison, Wisconsin53706-1322, United States."
  ],
  "article_type": "research article",
  "arxiv": null,
  "author_total": 3,
  "authors": [
    {
      "affs": [
        0
      ],
      "name": "Laura A Kopff",
      "orcid": "0009-0002-2800-2393"
    },
    {
      "affs": [
        0
      ],
      "name": "Brian J Esselman",
      "orcid": "0000-0002-9385-8078"
    },
    {
      "affs": [
        0
      ],
      "name": "Robert J McMahon",
      "orcid": "0000-0003-1377-5107"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/137w5tzcwwm53.bib",
  "cited_by": 0,
  "doi": "10.1021/acs.jpca.6c04620",
  "fulltext_url": "https://europepmc.org/articles/PMC13618054",
  "id": "137w5tzcwwm53",
  "issns": [
    "1089-5639",
    "1520-5215"
  ],
  "landing_url": "https://europepmc.org/article/MED/42917528",
  "language": "eng",
  "licence": "CC-BY",
  "licence_label": "CC BY",
  "licence_source": "article",
  "licence_url": "https://creativecommons.org/licenses/by/4.0/",
  "metadata_licence": null,
  "native_subjects": [
    [
      "openalex",
      "1606|Chemical Reactions and Mechanisms"
    ]
  ],
  "openalex": "W7212635130",
  "pdf_url": "https://europepmc.org/articles/PMC13618054?pdf=render",
  "pmcid": "PMC13618054",
  "pmid": "42917528",
  "published": "2026-09-01",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/137w5tzcwwm53.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:21:02Z",
      "native_id": "MED:42917528",
      "source": "europepmc",
      "url": "https://europepmc.org/article/MED/42917528"
    }
  ],
  "subjects": [
    {
      "field": "chemistry",
      "origin": "openalex:1606|Chemical Reactions and Mechanisms",
      "subfield": "physical"
    }
  ],
  "title": "Photochemistry and Spectroscopy of 2- and 3-Benzo[b]thienyl Diazomethane.",
  "title_text": "Photochemistry and Spectroscopy of 2- and 3-Benzo[b]thienyl Diazomethane.",
  "type": "peer-reviewed",
  "updated_at": "2026-10-30T12:21:02Z",
  "url": "https://research.draconitic.com/paper/137w5tzcwwm53",
  "venue": "The journal of physical chemistry. A",
  "versions": []
}