Nonheme Mononuclear and Dinuclear Iron(II) and Iron(III) Fluoride Complexes and Their Fluorine Radical Transfer Reactivity
Year: 2024
Type: article
Abstract: The nonheme iron(II) complexes containing a fluoride anion, Fe II (BNPA Ph2 O)(F) ( 1 ) and [Fe II (BNPA Ph2 OH)(F)(THF)](BF 4 ) ( 2 ), were synthesized and structurally characterized. Addition of dioxygen to either 1 or 2 led to the formation of a fluoride-bridged, dinuclear iron(III) complex [Fe 2 III (BNPA Ph2 O) 2 (F) 2 (μ-F)] + ( 4 ), which was characterized by single-crystal X-ray diffraction, 1 H NMR, and elemental analysis. An iron(II)(iodide) complex, Fe II (BNPA Ph2 O)(I) ( 3 ), was prepared and reacted with O 2 to give the mononuclear complex cis -Fe III (BNPA Ph2 O)(OH)(I) ( 5 ). Addition of excess fluoride to 5 led to the formation of the oxo-bridged, dinuclear iron(III) complex [Fe 2 III (BNPA Ph2 O) 2 (F) 2 (μ-O)] ( 6 ), while the mononuclear iron(III)(fluoride) complex cis -Fe III (BNPA Ph2 O)(F)(Cl) ( 7 ) was prepared from the addition of excess F – to Fe III (BNPA Ph2 O)Cl 2 . The dinuclear complexes 4 and 6 were unreactive to fluorine radical transfer, but mononuclear 7 reacts with the radical substrate ( p -MeO-C 6 H 4 ) 3 C • to give the fluorine radical transfer products Fe II (BNPA Ph2 O)(Cl) and ( p -OMe-C 6 H 4 ) 3 CF. These results show that a mononuclear Fe III (F) complex is capable of mediating fluorine radical transfer, even in the presence of second coordination sphere hydrogen bonds to the F – ligand. These findings are placed in context with what is known about the nonheme iron halogenases and related synthetic catalysts regarding their ability, or lack thereof, to mediate fluorine radical transfer reactions.
Source: Inorganic Chemistry
Institution: Johns Hopkins University
Language: English
Subfield: Inorganic Chemistry
Field: Chemistry
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W4405838702