{
  "abstract": "Radical–radical reactions of resonantly stabilized species such as propargyl (C3H3˙) and benzyl (C7H7˙) efficiently generate polycyclic aromatic hydrocarbons (PAHs). Key mechanisms—propargyl addition–benzannulation (PABA), methyl addition–ring expansion (MARE), and cyclopentadienyl addition–naphthylization (CPAN)—govern early-stage aromatic growth, but transforming these mechanisms to larger PAHs is computationally challenging due to combinatorial intermediates and reactions on excited state triplet surfaces. Here, we introduce a “periodic system” of PAHs that organizes aromatic growth according to transferable radical–radical motifs, enabling prediction of molecular evolution across the size regime. Using (2-naphthyl)-methyl (2-C11H9˙) and benzyl (C7H7˙) radicals as benchmarks, we experimentally demonstrate the predicted gas-phase formation of four- and five-ring PAHs, including (1) C18H12 isomers: tetracene, benz[a]anthracene, and [4]helicene; (2) C22H14 isomers: benzo[a]tetracene, benzo[a]tetraphene, and [5]helicene. Secondary hydrogen-loss and successive reactions produce even larger 2D and 3D aromatics, such as nanobowls and fullerenes, and their building blocks (corannulene and coronene). This framework provides a unifying and predictive description of PAH growth across combustion and circumstellar environments such as carbon-rich envelopes of late-type Asymptotic Giant Branch (AGB) stars and planetary nebulae.",
  "abstract_shown": true,
  "affiliations": [
    "National Synchrotron Radiation Laboratory, University of Science and Technology of China Hefei Anhui 230029 China",
    "School of New Energy Engineering, Hefei Institute of Technology Hefei Anhui 238076 China",
    "Department of Chemistry, University of Hawaii at Manoa Honolulu HI 96822 USA",
    "School of Nuclear Science and Technology, University of Science and Technology of China Hefei Anhui 230027 China"
  ],
  "article_type": "research article",
  "arxiv": null,
  "author_total": 7,
  "authors": [
    {
      "affs": [
        0,
        1
      ],
      "name": "Wang Li",
      "orcid": "0009-0006-1683-9320"
    },
    {
      "affs": [
        0
      ],
      "name": "Hu Ju"
    },
    {
      "affs": [
        0
      ],
      "name": "Ming-Gao Xu"
    },
    {
      "affs": [
        2
      ],
      "name": "Shane J. Goettl",
      "orcid": "0000-0003-1796-5725"
    },
    {
      "affs": [
        0
      ],
      "name": "Jiu-Zhong Yang",
      "orcid": "0000-0002-7076-3412"
    },
    {
      "affs": [
        0,
        3
      ],
      "name": "Long Zhao",
      "orcid": "0000-0002-6585-0028"
    },
    {
      "affs": [
        2
      ],
      "name": "Ralf I. Kaiser",
      "orcid": "0000-0002-7233-7206"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/2wjbnqeg09r3w.bib",
  "cited_by": 0,
  "doi": "10.1039/d6sc05859k",
  "fulltext_url": "https://pmc.ncbi.nlm.nih.gov/articles/PMC13548009/",
  "id": "2wjbnqeg09r3w",
  "issns": [
    "2041-6520",
    "2041-6539"
  ],
  "landing_url": "https://doi.org/10.1039/d6sc05859k",
  "language": "en",
  "licence": "CC-BY-NC-3.0",
  "licence_label": "CC BY-NC 3.0",
  "licence_source": "article",
  "licence_url": "https://creativecommons.org/licenses/by-nc/3.0/",
  "metadata_licence": null,
  "native_subjects": [
    [
      "heading",
      "Chemistry"
    ],
    [
      "openalex",
      "1605|Synthesis and Properties of Aromatic Compounds"
    ]
  ],
  "openalex": "W7211919198",
  "pdf_url": null,
  "pmcid": "PMC13548009",
  "pmid": "42707744",
  "published": "2026-09-07",
  "publisher": "Royal Society of Chemistry",
  "ris": "https://research.draconitic.com/paper/2wjbnqeg09r3w.ris",
  "sources": [
    {
      "first_seen": "2026-10-31T12:23:45Z",
      "native_id": "PMC13548009",
      "source": "pmc",
      "url": "https://doi.org/10.1039/d6sc05859k"
    }
  ],
  "subjects": [
    {
      "field": "chemistry",
      "origin": "openalex:1605|Synthesis and Properties of Aromatic Compounds",
      "subfield": "organic"
    }
  ],
  "title": "A periodic system of polycyclic aromatic hydrocarbons for predictive molecular growth processes",
  "title_text": "A periodic system of polycyclic aromatic hydrocarbons for predictive molecular growth processes",
  "type": "peer-reviewed",
  "updated_at": "2026-11-01T12:20:52Z",
  "url": "https://research.draconitic.com/paper/2wjbnqeg09r3w",
  "venue": "Chemical Science",
  "versions": []
}