{
  "abstract": "Endohedral nitrogen fullerenes are promising candidates for molecular spin qubits and quantum sensing. We compare nitrogen spin localization and N···C contact topology in N@C60 and N@C70. Baseline structural, vibrational, electronic, population, spin density, noncovalent interaction (NCI), and quantum theory of atoms in molecules (QTAIM) analyses used UB3LYP/6-31G(d). Counterpoise-corrected interaction energies were calculated using UB3LYP-D3(BJ)/def2-TZVP, with def2-QZVP checks. QTAIM sensitivity was assessed at fixed geometries using UB3LYP/def2-TZVP and UωB97X-D/def2-TZVP. Encapsulation leaves both cages essentially unperturbed: selected vibrational shifts are ≤0.8 cm−1 and HOMO–LUMO gap changes are ≤0.007 eV. Frontier orbitals remain cage-dominated, whereas Mulliken and Hirshfeld analyses assign 94–99% of the spin population to nitrogen, without substantial charge transfer. Counterpoise-corrected def2-TZVP interaction energies are −9.09 and −8.55 kcal mol−1, respectively; def2-QZVP changes each by <0.05 kcal mol−1. NCI/QTAIM descriptors indicate weak, low-density N···C contacts. N@C60 retains 60 connections across all three tested levels; N@C70 has eight at baseline and the same six in both def2-TZVP calculations. Thus, extensive and restricted contact networks remain distinct, although the exact N@C70 count and local descriptors depend on computational level. Predominantly nitrogen-centered spin therefore accompanies different surrounding contact topologies in cages that differ in size and shape.",
  "abstract_shown": true,
  "affiliations": [
    "Ahmet Erdoğan Vocational School of Health Services, Zonguldak Bülent Ecevit University, İbn-i Sina Campus, 67600 Zonguldak, Türkiye",
    "Department of Physics Engineering, Faculty of Engineering, Hacettepe University, 06800 Ankara, Türkiye"
  ],
  "article_type": null,
  "arxiv": null,
  "author_total": 2,
  "authors": [
    {
      "affs": [
        0
      ],
      "name": "Tuğba Göcen",
      "orcid": "0000-0003-0078-8531"
    },
    {
      "affs": [
        1
      ],
      "name": "Sevgi Haman Bayarı",
      "orcid": "0000-0001-9265-1414"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/4xvsc8h8v06c8.bib",
  "cited_by": 0,
  "doi": "10.3390/nano16211349",
  "fulltext_url": null,
  "id": "4xvsc8h8v06c8",
  "issns": [
    "2079-4991"
  ],
  "landing_url": "https://www.mdpi.com/2079-4991/16/21/1349",
  "language": null,
  "licence": "CC-BY-4.0",
  "licence_label": "CC BY 4.0",
  "licence_source": "article",
  "licence_url": "https://creativecommons.org/licenses/by/4.0/",
  "metadata_licence": null,
  "native_subjects": [
    [
      "openalex",
      "1605|Fullerene Chemistry and Applications"
    ]
  ],
  "openalex": "W7223574005",
  "pdf_url": null,
  "pmcid": null,
  "pmid": null,
  "published": "2026-10-24",
  "publisher": "MDPI AG",
  "ris": "https://research.draconitic.com/paper/4xvsc8h8v06c8.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:18:45Z",
      "native_id": "10.3390/nano16211349",
      "source": "crossref",
      "url": "https://www.mdpi.com/2079-4991/16/21/1349"
    }
  ],
  "subjects": [
    {
      "field": "chemistry",
      "origin": "openalex:1605|Fullerene Chemistry and Applications",
      "subfield": "organic"
    }
  ],
  "title": "Cage Geometry Reorganizes N···C Contacts While Preserving Nitrogen Spin Localization in N@C60 and N@C70: A DFT Study",
  "title_text": "Cage Geometry Reorganizes N···C Contacts While Preserving Nitrogen Spin Localization in N@C60 and N@C70: A DFT Study",
  "type": "peer-reviewed",
  "updated_at": "2026-10-30T12:18:45Z",
  "url": "https://research.draconitic.com/paper/4xvsc8h8v06c8",
  "venue": "Nanomaterials",
  "versions": []
}