{
  "abstract": "Polymethine dyes are widely used for NIR and SWIR imaging, yet their synthesis still relies on a single coupling paradigm that limits structural diversity and functionalization. Herein, we report a versatile, modular synthesis of heptamethine dyes based on an inverse-polarity approach. Readily available building blocks are converted into a ketone intermediate, which allows independent selection of heterocycles and the central ring system, as well as installation of 4′-substituents via organolithium addition. This intermediate can also be extended by aldehyde homologation to access undecamethine and longer red-shifted scaffolds. The method enables access to polymethine dyes that were previously inaccessible or difficult to synthesize, including dyes with varied central rings, alkyl substitution, and a tri-alkyne scaffold for multivalent bioconjugation. Notably, introducing a localized positive charge on the central ring greatly reduces aggregation and enhances aqueous solubility, allowing direct administration in saline for in vivo imaging without formulation. More than a route to tailored fluorophores, this inverse-polarity platform provides a general alternative to conventional polymethine synthesis and a design framework for engineering soluble, red-shifted, and targetable imaging probes.",
  "abstract_shown": true,
  "affiliations": [],
  "article_type": null,
  "arxiv": null,
  "author_total": 7,
  "authors": [
    {
      "name": "Fung-Kit Tang"
    },
    {
      "name": "Wenjun Liu",
      "orcid": "0009-0004-9696-4732"
    },
    {
      "name": "Xinyuan Li",
      "orcid": "0009-0005-0980-0092"
    },
    {
      "name": "Lei Guo",
      "orcid": "0000-0003-0013-3236"
    },
    {
      "name": "Xuemei Chen"
    },
    {
      "name": "Kevin D. Belfield"
    },
    {
      "name": "Shang Jia",
      "orcid": "0000-0001-6285-8959"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/7jk8m85fq491b.bib",
  "cited_by": 0,
  "doi": "10.26434/chemrxiv.15004512/v2",
  "fulltext_url": null,
  "id": "7jk8m85fq491b",
  "issns": [],
  "landing_url": "https://chemrxiv.org/doi/full/10.26434/chemrxiv.15004512/v2",
  "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|Luminescence and Fluorescent Materials"
    ]
  ],
  "openalex": "W7223173907",
  "pdf_url": "https://chemrxiv.org/doi/pdf/10.26434/chemrxiv.15004512/v2",
  "pmcid": null,
  "pmid": null,
  "published": "2026-10-21",
  "publisher": "American Chemical Society (ACS)",
  "ris": "https://research.draconitic.com/paper/7jk8m85fq491b.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:17:24Z",
      "native_id": "10.26434/chemrxiv.15004512",
      "source": "chemrxiv",
      "url": "https://chemrxiv.org/doi/full/10.26434/chemrxiv.15004512/v2"
    }
  ],
  "subjects": [
    {
      "field": "chemistry",
      "origin": "openalex:2505|Luminescence and Fluorescent Materials",
      "subfield": "materials-polymers"
    }
  ],
  "title": "Inverse-Polarity Approach Towards Modular, Red-Shifted, and Soluble Polymethine Fluorophores",
  "title_text": "Inverse-Polarity Approach Towards Modular, Red-Shifted, and Soluble Polymethine Fluorophores",
  "type": "preprint",
  "updated_at": "2026-10-30T12:17:24Z",
  "url": "https://research.draconitic.com/paper/7jk8m85fq491b",
  "venue": "ChemRxiv",
  "versions": []
}