{
  "abstract": "Optical initialization and readout of molecular electron spins in water remains challenging for 3d transition-metal complexes. Their Laporte-forbidden d-d transitions yield weak transition dipole moments, so optical spin detection in aqueous Cu(II) previously required ~1 M concentrations. Here we overcome this constraint through symmetry-breaking chelation. Coordinating Cu(II) with EDTA imposes a non-centrosymmetric ligand field with enhanced metal-ligand covalency, relaxing Laporte restrictions and amplifying d-d transition dipole moments. This design enhances absorption and magnetic circular dichroism by 7.3- and 5.6-fold, enabling ultrafast spin readout down to 100 μM with an apparent dephasing time T2^*~0.54 ns. As a proof-of-concept for selective molecular-spin sensing, histidine addition extends T_2^* to ~0.8 ns in a concentration-dependent manner, whereas glycine produces no measurable effect. These results show that symmetry breaking provides a strategy to create molecular spin-photon interfaces, opening avenues toward all-optical, analyte-responsive quantum sensing in water.",
  "abstract_shown": true,
  "affiliations": [],
  "article_type": null,
  "arxiv": "2610.24925",
  "author_total": 7,
  "authors": [
    {
      "name": "Jinlei Li"
    },
    {
      "name": "Qiaoyun Wu"
    },
    {
      "name": "Qiaoqiao Shao"
    },
    {
      "name": "Zhubin Hu"
    },
    {
      "name": "Haitao Sun"
    },
    {
      "name": "Zhenrong Sun"
    },
    {
      "name": "Donghai Feng"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/6v0ztbh8vrt62.bib",
  "cited_by": 0,
  "doi": "10.48550/arxiv.2610.24925",
  "fulltext_url": null,
  "id": "6v0ztbh8vrt62",
  "issns": [],
  "landing_url": "https://arxiv.org/abs/2610.24925",
  "language": null,
  "licence": "LicenseRef-arXiv-nonexclusive-1.0",
  "licence_label": "arXiv licence",
  "licence_source": "article",
  "licence_url": "http://arxiv.org/licenses/nonexclusive-distrib/1.0/",
  "metadata_licence": "CC0-1.0",
  "native_subjects": [
    [
      "arxiv",
      "quant-ph"
    ],
    [
      "openalex",
      "2504|Magnetism in coordination complexes"
    ]
  ],
  "openalex": "W7223004325",
  "pdf_url": "https://arxiv.org/pdf/2610.24925",
  "pmcid": null,
  "pmid": null,
  "published": "2026-10-18",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/6v0ztbh8vrt62.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:30:52Z",
      "native_id": "2610.24925",
      "source": "arxiv",
      "url": "https://arxiv.org/abs/2610.24925"
    }
  ],
  "subjects": [
    {
      "field": "physics",
      "origin": "arxiv:quant-ph",
      "subfield": "quantum"
    }
  ],
  "title": "Symmetry-breaking chelation enables room-temperature all-optical spin coherence readout of aqueous Cu(II) for chemoselective discrimination",
  "title_text": "Symmetry-breaking chelation enables room-temperature all-optical spin coherence readout of aqueous Cu(II) for chemoselective discrimination",
  "type": "preprint",
  "updated_at": "2026-11-06T18:21:01Z",
  "url": "https://research.draconitic.com/paper/6v0ztbh8vrt62",
  "venue": "arXiv",
  "versions": []
}