{
  "abstract": "The intense near-infrared band (700–1250 nm) of dioxidized porphyrin double-decker complexes, characterized by a metal ion sandwiched between two porphyrinato ligands bearing two holes in total, has been assigned to the HOMO→LUMO transition for three decades. Herein, we demonstrate that this band does not correspond to the lowest excited state. In the spectra of [Y(oep) 2 ] + and [Tb(oep) 2 ] + (oep = octaethylporphyrinato), we observed a weak band near 1430 nm, with 2–3% of the absorbance of the intense band (at 812 nm and 830 nm) and a much smaller dependence on the metal. Time-dependent density functional theory calculations with an optimally tuned functional assigned the weak and intense bands to S 1 and S 3 , respectively, i.e., a configuration-interaction pair of the HOMO→LUMO and HOMO−1→LUMO excitations. As observed in crystal structures reported earlier, the two rings are twisted by 30–36°, which lowers the symmetry from D 4d (45°) to D 4 . The weak band S 1 is symmetry-forbidden in D 4d and owes its low intensity to this twist. The calculated slope of S 3 against the ionic radius was within 3% of the experimental value, whereas S 1 was nearly independent of the metal. Therefore, the lowest excited states of these strongly coupled π dimers are nearly dark.",
  "abstract_shown": true,
  "affiliations": [
    "Department of Chemistry, Graduate School of Science, The University of Osaka, 1-1 Machikaneyama, Toyonaka, Osaka, Japan, 560-0043",
    "Innovative Catalysis Science Division, Institute for Open and Transdisciplinary Research Initiatives (ICS-OTRI)",
    "The University of Osaka"
  ],
  "article_type": null,
  "arxiv": null,
  "author_total": 2,
  "authors": [
    {
      "affs": [
        0
      ],
      "name": "Wataru Imanaka",
      "orcid": "0009-0005-0873-1558"
    },
    {
      "affs": [
        0,
        1,
        2
      ],
      "name": "Ken-ichi Yamashita",
      "orcid": "0000-0001-7270-1234"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/1zqgecq0d2r2j.bib",
  "cited_by": 0,
  "doi": "10.26434/chemrxiv.15010956/v1",
  "fulltext_url": null,
  "id": "1zqgecq0d2r2j",
  "issns": [],
  "landing_url": "https://chemrxiv.org/doi/full/10.26434/chemrxiv.15010956/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",
      "2505|Porphyrin and Phthalocyanine Chemistry"
    ]
  ],
  "openalex": "W7223296519",
  "pdf_url": "https://chemrxiv.org/doi/pdf/10.26434/chemrxiv.15010956/v1",
  "pmcid": null,
  "pmid": null,
  "published": "2026-10-23",
  "publisher": "American Chemical Society (ACS)",
  "ris": "https://research.draconitic.com/paper/1zqgecq0d2r2j.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:17:26Z",
      "native_id": "10.26434/chemrxiv.15010956",
      "source": "chemrxiv",
      "url": "https://chemrxiv.org/doi/full/10.26434/chemrxiv.15010956/v1"
    }
  ],
  "subjects": [
    {
      "field": "chemistry",
      "origin": "openalex:2505|Porphyrin and Phthalocyanine Chemistry",
      "subfield": "materials-polymers"
    }
  ],
  "title": "Reassignment of the Near-Infrared Absorption of Dioxidized Rare-Earth Porphyrin Double-Decker Complexes: Identification of a Nearly Dark Lowest Excited State",
  "title_text": "Reassignment of the Near-Infrared Absorption of Dioxidized Rare-Earth Porphyrin Double-Decker Complexes: Identification of a Nearly Dark Lowest Excited State",
  "type": "preprint",
  "updated_at": "2026-10-30T12:17:26Z",
  "url": "https://research.draconitic.com/paper/1zqgecq0d2r2j",
  "venue": "ChemRxiv",
  "versions": []
}