{
  "abstract": "Understanding chemical reactivity at cryogenic temperatures is essential for advancing both fundamental quantum science and next-generation catalytic technologies. At the single-atom limit, geometric confinement can promote ground-state electronic effects that drive novel chemical events without thermal activation. Using the H2 interaction with transition-metal nanocontacts as a benchmark, we report the barrierless formation of a transient tip complex characterized by a diborane-like 4-electron, 3-center bond (Pt–H ~0.17 and 0.18 nm). This 2 ground-state dissociation acts as a selective quantum channel modifier: while the intact, physisorbed molecule yields a conductance of ~0.2 G0, the dissociated transient complex results in a quantized conductance of 1 G0. This mechanism is correctly captured by mean-field orbital models when proper non-local exchange corrections are effectively considered. Furthermore, while bulk palladium is renowned for its high hydrogen affinity, our mean-field models and quantum calculations demonstrate the opposite: Pd nanocontacts merely physisorb H2 (H–H ~0.08 nm), behaving as a noble metal at this quantum limit. These findings illustrate how geometric confinement can drive novel chemical events, opening new avenues for zerotemperature catalysis at the single-atom limit.",
  "abstract_shown": true,
  "affiliations": [
    "ESIT – School of Engineering and Technology",
    "International University of La Rioja (UNIR"
  ],
  "article_type": null,
  "arxiv": null,
  "author_total": 2,
  "authors": [
    {
      "affs": [
        0,
        1
      ],
      "name": "Yamila García"
    },
    {
      "name": "Yamila Garcia-Martinez",
      "orcid": "0000-0001-8054-9877"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/eb4yra0p9zt2p.bib",
  "cited_by": 0,
  "doi": "10.26434/chemrxiv.15009624/v1",
  "fulltext_url": null,
  "id": "eb4yra0p9zt2p",
  "issns": [],
  "landing_url": "https://chemrxiv.org/doi/full/10.26434/chemrxiv.15009624/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",
      "2208|Molecular Junctions and Nanostructures"
    ]
  ],
  "openalex": "W7214768941",
  "pdf_url": "https://chemrxiv.org/doi/pdf/10.26434/chemrxiv.15009624/v1",
  "pmcid": null,
  "pmid": null,
  "published": "2026-09-29",
  "publisher": "American Chemical Society (ACS)",
  "ris": "https://research.draconitic.com/paper/eb4yra0p9zt2p.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:17:21Z",
      "native_id": "10.26434/chemrxiv.15009624",
      "source": "chemrxiv",
      "url": "https://chemrxiv.org/doi/full/10.26434/chemrxiv.15009624/v1"
    }
  ],
  "subjects": [
    {
      "field": "chemistry",
      "origin": "source:chemrxiv",
      "subfield": "general"
    }
  ],
  "title": "Confinement-Driven Transient Coordination Complexes: H2 Dissociation and Quantum Channel Modification in Single-Atom Contacts",
  "title_text": "Confinement-Driven Transient Coordination Complexes: H2 Dissociation and Quantum Channel Modification in Single-Atom Contacts",
  "type": "preprint",
  "updated_at": "2026-10-30T12:17:21Z",
  "url": "https://research.draconitic.com/paper/eb4yra0p9zt2p",
  "venue": "ChemRxiv",
  "versions": []
}