{
  "abstract": "Artificial metalloenzymes (ArMs) that incorporate organometallic fragments through direct metal–protein coordination open the door to unlock the full evolutionary potential of the protein scaffold to modulate catalysis. This work builds on our previously published work, in which Ru(II) piano stool complexes bearing bipyridyl ligands were used to deliver [Ru(Arene)]2+ fragments into a naïve protein scaffold, generating a transfer-hydrogenase artificial metalloenzyme. Here we systematically explore Ru(II) piano stool complexes bearing pyridyl–N-heterocyclic carbene (Pyr–NHC) bidentate ligands as active-site precursors for metathases and transfer hydrogenases. In this work we describe the synthesis and characterisation of five novel Ru(II) piano stool complexes bearing a hexamethylbenzene (HMB) arene cap and Pyr–NHC bidentate ligands, in which systematic variation of the NHC wingtip substituent (R′ = Me, Et, iPr, Ph) and the pyridine ring substituent (R = H, F) tunes the steric and electronic properties of the complex. Single-crystal X-ray analysis and electrochemical studies show that the strong σ-donation from the carbene lowers the Ru(II/III) redox potential and elongates the Ru–HMB bond relative to their bipyridyl counterparts. This supports displacement of the arene as opposed to the bidentate ligand in the presence of protein. Systematic comparison between Pyr–NHC and bipyridyl complexes also provided an insight into the influence of the arene and the bidentate ligand on the structural and electrochemical properties of these complexes.",
  "abstract_shown": true,
  "affiliations": [
    "Yusuf Hamied Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge, United Kingdom, CB2 1EW"
  ],
  "article_type": null,
  "arxiv": null,
  "author_total": 12,
  "authors": [
    {
      "affs": [
        0
      ],
      "name": "Armando Albert Flores",
      "orcid": "0000-0002-3996-5155"
    },
    {
      "affs": [
        0
      ],
      "name": "Matthew G. Wheeler"
    },
    {
      "affs": [
        0
      ],
      "name": "Oskar James Klein"
    },
    {
      "affs": [
        0
      ],
      "name": "George S. Biggs"
    },
    {
      "affs": [
        0
      ],
      "name": "Jonathan Shaw"
    },
    {
      "affs": [
        0
      ],
      "name": "Jonathan Bostock"
    },
    {
      "affs": [
        0
      ],
      "name": "Victoria Daramy-Williams"
    },
    {
      "affs": [
        0
      ],
      "name": "Max Lambert"
    },
    {
      "affs": [
        0
      ],
      "name": "Natasha Usselmann"
    },
    {
      "affs": [
        0
      ],
      "name": "Andrew D. Bond"
    },
    {
      "affs": [
        0
      ],
      "name": "Sally R. Boss",
      "orcid": "0000-0002-6194-1889"
    },
    {
      "affs": [
        0
      ],
      "name": "Paul D. Barker",
      "orcid": "0000-0003-0094-0054"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/70szz6r5d9hhw.bib",
  "cited_by": 0,
  "doi": "10.26434/chemrxiv.15010193/v1",
  "fulltext_url": null,
  "id": "70szz6r5d9hhw",
  "issns": [],
  "landing_url": "https://chemrxiv.org/doi/full/10.26434/chemrxiv.15010193/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",
      "1605|N-Heterocyclic Carbenes in Organic and Inorganic Chemistry"
    ]
  ],
  "openalex": "W7221186312",
  "pdf_url": "https://chemrxiv.org/doi/pdf/10.26434/chemrxiv.15010193/v1",
  "pmcid": null,
  "pmid": null,
  "published": "2026-10-09",
  "publisher": "American Chemical Society (ACS)",
  "ris": "https://research.draconitic.com/paper/70szz6r5d9hhw.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:17:22Z",
      "native_id": "10.26434/chemrxiv.15010193",
      "source": "chemrxiv",
      "url": "https://chemrxiv.org/doi/full/10.26434/chemrxiv.15010193/v1"
    }
  ],
  "subjects": [
    {
      "field": "chemistry",
      "origin": "openalex:1605|N-Heterocyclic Carbenes in Organic and Inorganic Chemistry",
      "subfield": "organic"
    }
  ],
  "title": "Selective Ligand Replacement Leads to Carbene Complexes as Catalysts in Proteins",
  "title_text": "Selective Ligand Replacement Leads to Carbene Complexes as Catalysts in Proteins",
  "type": "preprint",
  "updated_at": "2026-10-30T12:17:22Z",
  "url": "https://research.draconitic.com/paper/70szz6r5d9hhw",
  "venue": "ChemRxiv",
  "versions": []
}