The Fe₂(NO)₂ Diamond Core: A Unique Structural Motif In Non‐Heme Iron–NO Chemistry

Abstract

This is the author manuscript accepted for publication and has undergone full peer review but has not been through the copyediting, typesetting, pagination and proofreading process, which may lead to differences between this version and the Version of Record.

Reactivity of Thiolate and Hydrosulfide with a Mononuclear {FeNO}7 Complex Featuring a Very High N–O Stretching Frequency

“…The frozen solution EPR spectrum of 2 at 80K showed a slightly rhombic S = 3/2 signal with apparent < g> values of 1.994 and 3.889 (Figure c) as expected for a {FeNO} 7 species. Very similar EPR spectra with similar g values have been reported in the literature for five-coordinate (rhombic) , and six-coordinate (rhombic [refs , ]/axial [refs ,, ]) {FeNO} 7 complexes.). The g x , g y , g z values, and zero field splitting parameters obtained from SQUID fit of 2 were used to fit the EPR spectra to the Spin Hamiltonian using “Spin Software” developed by Andrzej Ozarowski (Figure c).…”

“…Reduction potential values ranging from E pc = −1.02 V to −1.14 V (vs Cp 2 Fe + /Cp 2 Fe) for the {FeNO} 7 /{FeNO} 8 reduction events (although irreversible reduction events) have previously been reported for mono- , and dinitrosyl , diiron complexes. Nearly reversible reduction events for five-coordinate ( E 1/2 = −1.34 V; −1.38 V; −1.48 to −1.60 V vs Cp 2 Fe + /Cp 2 Fe) and six-coordinate ( E 1/2 = −0.69 V; E pc = −1.03 V and −2.0 V; vs Cp 2 Fe + /Cp 2 Fe) {FeNO} 7 complexes have also been reported and these reduction events have been attributed to the reduction of the {FeNO} 7 units to the respective {FeNO} 8 units.…”

The Fe2(NO)2 Diamond Core: A Unique Structural Motif In Non‐Heme Iron–NO Chemistry

“…[18] This indicates that the linear Fe-N-O angle in 1 originates from electronic factors,t hat is,avery covalent Fe-NO bond due to an electron-poor Fe center. [21] Angewandte Chemie Zuschriften stretch must have somehow shifted to significantly lower energy (< 1500 cm À1 ). TheU V/Vis spectroscopic titration of 1 with CoCp 2 shows acomplete transformation of 1 with one equivalent of reductant via appearance of an ew, highly intense band at 445 nm ( Figure S2).…”

“…Crystal structure of complex 2 with thermal ellipsoids set at 50 %p robability.T he triflate counter anion, solvent molecules, and hydrogen atoms are omitted for clarity [21]. …”

Nitrite Formation at a Diiron Dinitrosyl Complex

“…Analysis of the reaction mixture by EPR and IR did not show conclusive evidence for the formation of dinitrosyl iron complex (DNIC) or Fe 2 (NO) 2 diamond core species (see Supporting Information). 44 It has been previously shown by Lehnert et al 24,25,45 and Meyer et al 33 that an electron-rich environment and a close N•••N distance are crucial for efficient N 2 O production. The electron-poor nature of the Py 4 DMcT ligand as well as the long N•••N distance in {FeNO} 7 2 (4.750 Å versus 2.803 Å in the case of Lehnert et al 24,25,45 ), likely hinders the formation of the N−N bond necessary for N 2 O production.…”