{
  "abstract": "Nuclear-spin quantum sensing requires coherent molecular electron spin qubits embedded in analyte-recognizing local environments that bring target nuclei into their short-range hyperfine detection volume. Here, we introduce TA-TEMPO, a covalent organic framework in which dilute nitroxide radicals and Li + -binding triazine moieties form defect-engineered recognition pockets for room-temperature 7 Li sensing. Optimizing radical density preserves spin coherence while maximizing the 7 Li/ 1 H response acquired by hyperfine spectroscopy. TA-TEMPO detects Li + in a tetrahydrofuran solution of LiBr with a sensitivity of 1.0 × 10 −4 mol·L −1 at room temperature, a 50-fold improvement over the previous benchmark, and enables quantum sensing across several lithium-based electrolytes. Control experiments and density functional theory calculations show that triazine sites preferentially bind Li + over Na + and position it near nitroxide radicals, accounting for selective detection in a large excess of Na + . These results establish chemically programmed host-guest recognition as a strategy to integrate sensitivity, selectivity, and coherent spin readout in porous molecular quantum sensors.",
  "abstract_shown": true,
  "affiliations": [
    "Department of Chemistry, School of Science and Research Center for Industries of the Future",
    "Westlake University",
    "Institute of Natural Sciences",
    "Westlake Institute for Advanced Study",
    "Department of Materials Science and Engineering and Research Center for Industries of the Future",
    "School of Science and Research Center for Industries of the Future"
  ],
  "article_type": null,
  "arxiv": null,
  "author_total": 5,
  "authors": [
    {
      "affs": [
        0,
        1,
        2,
        3
      ],
      "name": "Zhecheng Sun"
    },
    {
      "affs": [
        4,
        1
      ],
      "name": "Chang Tang"
    },
    {
      "affs": [
        5,
        1
      ],
      "name": "Guangfu Ni"
    },
    {
      "affs": [
        4,
        1
      ],
      "name": "Zexin Jin"
    },
    {
      "affs": [
        0,
        1,
        2,
        3,
        5
      ],
      "name": "Lei Sun",
      "orcid": "0000-0001-8467-6750"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/cap8e8q1w3sx6.bib",
  "cited_by": 0,
  "doi": "10.26434/chemrxiv.15007348/v2",
  "fulltext_url": null,
  "id": "cap8e8q1w3sx6",
  "issns": [],
  "landing_url": "https://chemrxiv.org/doi/full/10.26434/chemrxiv.15007348/v2",
  "language": null,
  "licence": "CC-BY-NC-ND",
  "licence_label": "CC BY-NC-ND",
  "licence_source": "journal",
  "licence_url": "https://creativecommons.org/licenses/by-nc-nd/4.0/",
  "metadata_licence": null,
  "native_subjects": [
    [
      "openalex",
      "1304|Electron Spin Resonance Studies"
    ]
  ],
  "openalex": "W7220416114",
  "pdf_url": "https://chemrxiv.org/doi/pdf/10.26434/chemrxiv.15007348/v2",
  "pmcid": null,
  "pmid": null,
  "published": "2026-10-04",
  "publisher": "American Chemical Society (ACS)",
  "ris": "https://research.draconitic.com/paper/cap8e8q1w3sx6.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:17:22Z",
      "native_id": "10.26434/chemrxiv.15007348",
      "source": "chemrxiv",
      "url": "https://chemrxiv.org/doi/full/10.26434/chemrxiv.15007348/v2"
    }
  ],
  "subjects": [
    {
      "field": "biochemistry",
      "origin": "openalex:1304|Electron Spin Resonance Studies",
      "subfield": "biophysics"
    }
  ],
  "title": "Quantum Sensing of Lithium Ions with Defect-Engineered Recognition Pockets in a TEMPO-Modified Covalent Organic Framework",
  "title_text": "Quantum Sensing of Lithium Ions with Defect-Engineered Recognition Pockets in a TEMPO-Modified Covalent Organic Framework",
  "type": "preprint",
  "updated_at": "2026-10-30T12:17:22Z",
  "url": "https://research.draconitic.com/paper/cap8e8q1w3sx6",
  "venue": "ChemRxiv",
  "versions": []
}