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Masked Radicals: Iron Complexes of Trityl, Benzophenone, and Phenylacetylene.

ABSTRACT: We report the first Fe─CPh₃ complex, and show that the long Fe─C bond can be disrupted by neutral π-acceptor ligands (benzophenone and phenylacetylene) to release the triphenylmethyl radical. The products are formally iron(I) complexes, but X-ray absorption spectroscopy coupled with density functional and multireference ab initio calculations indicates that the best description of all the complexes is iron(II). In the formally iron(I) complexes, this does not imply that the π-acceptor ligand has radical character, because the iron(II) description arises from doubly-occupied frontier molecular orbitals that are shared equitably by the iron and the π-acceptor ligand, and the unpaired electrons lie on the metal. Despite the lack of substantial radical character on the ligands, alkyne and ketone fragments can couple to form a high-spin iron(III) complex with a cyclized metalladihydrofuran core.

SUBMITTER: MacLeod KC

PROVIDER: S-EPMC8184022 | biostudies-literature | 2019 Nov

REPOSITORIES: biostudies-literature

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Masked Radicals: Iron Complexes of Trityl, Benzophenone, and Phenylacetylene.

MacLeod K Cory KC DiMucci Ida M IM Zovinka Edward P EP McWilliams Sean F SF Mercado Brandon Q BQ Lancaster Kyle M KM Holland Patrick L PL

Organometallics 20191010 21

We report the first Fe─CPh<sub>3</sub> complex, and show that the long Fe─C bond can be disrupted by neutral π-acceptor ligands (benzophenone and phenylacetylene) to release the triphenylmethyl radical. The products are formally iron(I) complexes, but X-ray absorption spectroscopy coupled with density functional and multireference <i>ab initio</i> calculations indicates that the best description of all the complexes is iron(II). In the formally iron(I) complexes, this does not imply that the π-a ...[more]

PMID: 34103782

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