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Tripodi G, Roithová J. Unmasking the Iron-Oxo Bond of the [(Ligand)Fe-OIAr] 2+/+ Complexes. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2022; 33:1636-1643. [PMID: 35920859 PMCID: PMC9460779 DOI: 10.1021/jasms.2c00094] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/31/2022] [Revised: 07/26/2022] [Accepted: 07/26/2022] [Indexed: 06/15/2023]
Abstract
ArIO (ArI = 2-(tBuSO2)C6H4I) is an oxidant used to oxidize FeII species to their FeIV-oxo state, enabling hydrogen-atom transfer (HAT) and oxygen-atom transfer (OAT) reactions at low energy barriers. ArIO, as a ligand, generates masked Fen═O species of the type Fe(n-2)-OIAr. Herein, we used gas-phase ion-molecule reactions and DFT calculations to explore the properties of masked iron-oxo species and to understand their unmasking mechanisms. The theory shows that the I-O bond cleavage in [(TPA)FeIVO(ArIO)]2+ (12+, TPA = tris(2-pyridylmethyl)amine)) is highly endothermic; therefore, it can be achieved only in collision-induced dissociation of 12+ leading to the unmasked iron(VI) dioxo complex. The reduction of 12+ by HAT leads to [(TPA)FeIIIOH(ArIO)]2+ with a reduced energy demand for the I-O bond cleavage but is, however, still endothermic. The exothermic unmasking of the Fe═O bond is predicted after one-electron reduction of 12+ or after OAT reactivity. The latter leads to the 4e- oxidation of unsaturated hydrocarbons: The initial OAT from [(TPA)FeIVO(ArIO)]2+ leads to the epoxidation of an alkene and triggers the unmasking of the second Fe═O bond still within one collisional complex. The second oxidation step starts with HAT from a C-H bond and follows with the rebound of the C-radical and the OH group. The process starting with the one-electron reduction could be studied with [(TQA)FeIVO(ArIO)]2+ (22+, TQA = tris(2-quinolylmethyl)amine)) because it has a sufficient electron affinity for electron transfer with alkenes. Accordingly, the reaction of 22+ with 2-carene leads to [(TQA)FeIIIO(ArIO)]2+ that exothermically eliminates ArI and unmasks the reactive FeV-dioxo species.
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Kephart JA, Hecht Z, Livesay BN, Bhowmick I, Shores MP, Popescu VC, Arulsamy N, Hulley EB. Self-assembly of an organometallic Fe 9O 6 cluster from aerobic oxidation of (tmeda)Fe(CH 2tBu) 2. Chem Commun (Camb) 2020; 56:4994-4997. [PMID: 32239066 DOI: 10.1039/d0cc00011f] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Aerobic oxidation of (tmeda)Fe(CH2tBu)2 in toluene or THF solution leads to the self-assembly of a magic-sized all-ferrous oxide cluster containing the Fe9O6 subunit and bearing organometallic and diamine ligands. Mössbauer studies of the cluster are consistent with an all-ferrous assignment and magnetometry reveals complex intracluster and intercluster magnetic interactions.
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Parchomyk T, Koszinowski K. Solution and Gas-Phase Reactivity of Me12
Fe8
−
and Related Cluster Ions. Chemistry 2017; 23:3213-3219. [DOI: 10.1002/chem.201605602] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2016] [Indexed: 11/05/2022]
Affiliation(s)
- Tobias Parchomyk
- Institut für Organische und Biomolekulare Chemie; Georg-August-Universität Göttingen; Tammannstr. 2 37077 Göttingen Germany
| | - Konrad Koszinowski
- Institut für Organische und Biomolekulare Chemie; Georg-August-Universität Göttingen; Tammannstr. 2 37077 Göttingen Germany
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Zhao P, Lei H, Ni C, Guo JD, Kamali S, Fettinger JC, Grandjean F, Long GJ, Nagase S, Power PP. Quasi-three-coordinate iron and cobalt terphenoxide complexes {Ar(iPr8)OM(μ-O)}2 (Ar(iPr8) = C6H-2,6-(C6H2-2,4,6-(i)Pr3)2-3,5-(i)Pr2; M = Fe or Co) with M(III)2(μ-O)2 core structures and the peroxide dimer of 2-oxepinoxy relevant to benzene oxidation. Inorg Chem 2015; 54:8914-22. [PMID: 26331405 DOI: 10.1021/acs.inorgchem.5b00930] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The bis(μ-oxo) dimeric complexes {Ar(iPr8)OM(μ-O)}2 (Ar(iPr8) = C6H-2,6-(C6H2-2,4,6-(i)Pr3)2-3,5-(i)Pr2; M = Fe (1), Co (2)) were prepared by oxidation of the M(I) half-sandwich complexes {Ar(iPr8)M(η(6)-arene)} (arene = benzene or toluene). Iron species 1 was prepared by reacting {Ar(iPr8)Fe(η(6)-benzene)} with N2O or O2, and cobalt species 2 was prepared by reacting {Ar(iPr8)Co(η(6)-toluene)} with O2. Both 1 and 2 were characterized by X-ray crystallography, UV-vis spectroscopy, magnetic measurements, and, in the case of 1, Mössbauer spectroscopy. The solid-state structures of both compounds reveal unique M2(μ-O)2 (M = Fe (1), Co(2)) cores with formally three-coordinate metal ions. The Fe···Fe separation in 1 bears a resemblance to that in the Fe2(μ-O)2 diamond core proposed for the methane monooxygenase intermediate Q. The structural differences between 1 and 2 are reflected in rather differing magnetic behavior. Compound 2 is thermally unstable, and its decomposition at room temperature resulted in the oxidation of the Ar(iPr8) ligand via oxygen insertion and addition to the central aryl ring of the terphenyl ligand to produce the 5,5'-peroxy-bis[4,6-(i)Pr2-3,7-bis(2,4,6-(i)Pr3-phenyl)oxepin-2(5H)-one] (3). The structure of the oxidized terphenyl species is closely related to that of a key intermediate proposed for the oxidation of benzene.
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Affiliation(s)
- Pei Zhao
- Department of Chemistry, University of California , Davis, California 95616, United States
| | - Hao Lei
- Department of Chemistry, University of California , Davis, California 95616, United States
| | - Chengbao Ni
- Department of Chemistry, University of California , Davis, California 95616, United States
| | - Jing-Dong Guo
- Fukui Institute for Fundamental Chemistry, Kyoto University , Takano-Nishihiraki-cho, Sakyo-ku, Kyoto 606-8103, Japan
| | - Saeed Kamali
- Department of Chemistry, University of California , Davis, California 95616, United States
| | - James C Fettinger
- Department of Chemistry, University of California , Davis, California 95616, United States
| | - Fernande Grandjean
- Department of Chemistry, Missouri University of Science and Technology, University of Missouri , Rolla, Missouri 65409-0010, United States
| | - Gary J Long
- Department of Chemistry, Missouri University of Science and Technology, University of Missouri , Rolla, Missouri 65409-0010, United States
| | - Shigeru Nagase
- Fukui Institute for Fundamental Chemistry, Kyoto University , Takano-Nishihiraki-cho, Sakyo-ku, Kyoto 606-8103, Japan
| | - Philip P Power
- Department of Chemistry, University of California , Davis, California 95616, United States
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