{
  "abstract": "Designing solid-state spin-qubit arrays that retain long coherence at high spin density remains a central challenge in quantum information materials. In molecular qubits, this challenge arises because the same local coordination environment and lattice architecture that define the spin array also control the dominant decoherence channels, most notably nuclear-spin spectral diffusion and coupling to low-frequency phonons. Metal–organic frameworks (MOFs) are therefore especially attractive because they combine dense, crystalline spin arrays with chemically programmable control over the coordination environment, framework connectivity, and supramolecular packing, yet a fundamental understanding of how specific structural changes translate into predictable relaxation behavior remains underdeveloped. Here we compare two closely related oxygen-coordinated Cu(II) frameworks, Cu-TPTC and Cu-TPTriC, that preserve the same first-sphere donor set while changing connectivity and supramolecular packing. Cu-TPTC comprises one-dimensional Cu–O chains assembled into hydrogen-bonded rods, whereas Cu-TPTriC forms coordination-connected Cu–O–Cu two-dimensional sheets that stack through interlayer aromatic contacts in the absence of hydrogen-bond stitching. Continuous-wave electron paramagnetic resonance (CW-EPR) spectroscopy shows that both lattices exhibit relatively narrow linewidths compared with a Cu–N porphyrinic benchmark, consistent with reduced ligand-derived superhyperfine broadening in an oxygenonly coordination sphere. Pulsed electron paramagnetic resonance measurements establish coherent spin control and reveal systematically longer spin–lattice relaxation times (T1) and phase-memory times (Tm) in Cu-TPTriC over 5–25 K, with Tm≈4.8 ± 0.011 μs at 5 K. This coherence gain persists despite substantially shorter Cu···Cu separations in Cu-TPTriC and is consistent with a reduced proton-bath density and modified lattice dynamics, as reflected in the weaker electron spin echo envelope modulation (ESEEM) observed for Cu-TPTriC. Together, these results suggest that within dense oxygen-coordinated Cu(II) framework lattices, the secondary-sphere nuclear-spin environment and lattice dynamics can play an important role in governing decoherence, potentially outweighing spin spacing alone.",
  "abstract_shown": true,
  "affiliations": [
    "Department of Chemistry and Biochemistry",
    "University of Texas at El Paso",
    "Department of Physics & Astronomy, University of Utah, 115S, 1400E, Salt Lake City, UT, 84112",
    "Center for Integrated Nanotechnologies, Sandia National Laboratories",
    "Department of Materials Science and Engineering",
    "University of Florida",
    "Bruker Biospin Corporation"
  ],
  "article_type": null,
  "arxiv": null,
  "author_total": 12,
  "authors": [
    {
      "affs": [
        0,
        1
      ],
      "name": "Kavish Saini"
    },
    {
      "affs": [
        0,
        1
      ],
      "name": "Sisheed Sivaraman"
    },
    {
      "affs": [
        2
      ],
      "name": "Prashanna Poudel"
    },
    {
      "affs": [
        2
      ],
      "name": "Bonaventure A. Odeke"
    },
    {
      "affs": [
        3
      ],
      "name": "Gajadhar Joshi"
    },
    {
      "affs": [
        3,
        4,
        5
      ],
      "name": "Manny de Jesus Lopez"
    },
    {
      "affs": [
        6
      ],
      "name": "Alvaro Montoya"
    },
    {
      "affs": [
        6
      ],
      "name": "Kalina Ranguelova"
    },
    {
      "affs": [
        3
      ],
      "name": "C. Thomas Harris"
    },
    {
      "affs": [
        3
      ],
      "name": "Ezra Bussmann"
    },
    {
      "affs": [
        2
      ],
      "name": "Christoph Boehme"
    },
    {
      "name": "Sreeprasad T Sreenivasan",
      "orcid": "0000-0002-5728-0512"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/cyvzgd0b683n1.bib",
  "cited_by": 0,
  "doi": "10.26434/chemrxiv.15009351/v1",
  "fulltext_url": null,
  "id": "cyvzgd0b683n1",
  "issns": [],
  "landing_url": "https://chemrxiv.org/doi/full/10.26434/chemrxiv.15009351/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",
      "2504|Magnetism in coordination complexes"
    ]
  ],
  "openalex": "W7214109021",
  "pdf_url": "https://chemrxiv.org/doi/pdf/10.26434/chemrxiv.15009351/v1",
  "pmcid": null,
  "pmid": null,
  "published": "2026-09-23",
  "publisher": "American Chemical Society (ACS)",
  "ris": "https://research.draconitic.com/paper/cyvzgd0b683n1.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:17:21Z",
      "native_id": "10.26434/chemrxiv.15009351",
      "source": "chemrxiv",
      "url": "https://chemrxiv.org/doi/full/10.26434/chemrxiv.15009351/v1"
    }
  ],
  "subjects": [
    {
      "field": "chemistry",
      "origin": "openalex:2504|Magnetism in coordination complexes",
      "subfield": "materials-polymers"
    }
  ],
  "title": "Framework Connectivity Tunes the Nuclear Spin Bath and Extends Coherence in Cu(II) Metal–Organic Framework Qubit Lattices",
  "title_text": "Framework Connectivity Tunes the Nuclear Spin Bath and Extends Coherence in Cu(II) Metal–Organic Framework Qubit Lattices",
  "type": "preprint",
  "updated_at": "2026-10-30T12:17:21Z",
  "url": "https://research.draconitic.com/paper/cyvzgd0b683n1",
  "venue": "ChemRxiv",
  "versions": []
}