{
  "abstract": "Antiaromatic 4nπ-electron circuits provide a powerful strategy for narrowing the HOMO–LUMO gaps of π-conjugated molecules, yet their contribution is often attenuated or obscured in stable polycyclic frameworks by competing local aromatic stabilization. Here we report a systematic series of thienocyclopenta-fused pyrenes containing one ( 1TP ), two ( trans -2TP and cis -2TP ), or four ( 4TP ) fused thienocyclopentadiene units, designed to evaluate the stepwise contributions of embedded 16π-electron circuits. The molecules were synthesized through Suzuki–Miyaura coupling followed by palladium-mediated annulation. Notably, 4TP was isolated as an air- and ambient-light-stable green solid, and its structure was confirmed by single-crystal X-ray diffraction. Comparative 1 H NMR analysis revealed a progressive upfield shift of diagnostic protons upon increasing the number of fused thienocyclopentadiene units, indicating the emergence and amplification of a paratropic ring-current effect. Theoretical calculations supported the emergence and strengthening of 16π-electron antiaromatic contributions in the two 2TP isomers and 4TP . Frontierorbital calculations and cyclic voltammetry further showed that the LUMO level is substantially stabilized whereas the HOMO level remains nearly unchanged, resulting in a systematic decrease in the HOMO–LUMO gaps. These results establish thienocyclopenta fusion as an effective molecular design strategy for controlling the antiaromatic contribution of 16π-electron circuits within a stable carbon-rich π-framework.",
  "abstract_shown": true,
  "affiliations": [
    "Institute for Molecular Science",
    "Graduate School of Engineering, Nagoya Institute of Technology, Gokiso-cho, Showa-ku, Aichi, Japan, 466-8555",
    "Graduate University for Advanced Studies, SOKENDAI"
  ],
  "article_type": null,
  "arxiv": null,
  "author_total": 3,
  "authors": [
    {
      "affs": [
        0,
        1
      ],
      "name": "Kenji Tsukamoto"
    },
    {
      "affs": [
        1
      ],
      "name": "Koji Takagi"
    },
    {
      "affs": [
        0,
        2
      ],
      "name": "Yasutomo Segawa",
      "orcid": "0000-0001-6439-8546"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/7hhdeqhhv7jrf.bib",
  "cited_by": 0,
  "doi": "10.26434/chemrxiv.15009883/v1",
  "fulltext_url": null,
  "id": "7hhdeqhhv7jrf",
  "issns": [],
  "landing_url": "https://chemrxiv.org/doi/full/10.26434/chemrxiv.15009883/v1",
  "language": null,
  "licence": "CC-BY",
  "licence_label": "CC BY",
  "licence_source": "journal",
  "licence_url": "https://creativecommons.org/licenses/by/4.0/",
  "metadata_licence": null,
  "native_subjects": [
    [
      "openalex",
      "1605|Synthesis and Properties of Aromatic Compounds"
    ]
  ],
  "openalex": "W7220434119",
  "pdf_url": "https://chemrxiv.org/doi/pdf/10.26434/chemrxiv.15009883/v1",
  "pmcid": null,
  "pmid": null,
  "published": "2026-10-05",
  "publisher": "American Chemical Society (ACS)",
  "ris": "https://research.draconitic.com/paper/7hhdeqhhv7jrf.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:17:22Z",
      "native_id": "10.26434/chemrxiv.15009883",
      "source": "chemrxiv",
      "url": "https://chemrxiv.org/doi/full/10.26434/chemrxiv.15009883/v1"
    }
  ],
  "subjects": [
    {
      "field": "chemistry",
      "origin": "openalex:1605|Synthesis and Properties of Aromatic Compounds",
      "subfield": "organic"
    }
  ],
  "title": "Fusion-Number-Dependent Emergence of 16π-Electron Antiaromatic Circuits in Thienocyclopenta-Fused Pyrenes",
  "title_text": "Fusion-Number-Dependent Emergence of 16π-Electron Antiaromatic Circuits in Thienocyclopenta-Fused Pyrenes",
  "type": "preprint",
  "updated_at": "2026-10-30T12:17:22Z",
  "url": "https://research.draconitic.com/paper/7hhdeqhhv7jrf",
  "venue": "ChemRxiv",
  "versions": []
}