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Le Dé Q, Bouammali A, Bijani C, Vendier L, Del Rosal I, Valyaev DA, Dinoi C, Simonneau A. An Experimental and Computational Investigation Rules Out Direct Nucleophilic Addition on the N 2 Ligand in Manganese Dinitrogen Complex [Cp(CO) 2 Mn(N 2 )]. Angew Chem Int Ed Engl 2023; 62:e202305235. [PMID: 37379032 DOI: 10.1002/anie.202305235] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2023] [Revised: 06/27/2023] [Accepted: 06/28/2023] [Indexed: 06/29/2023]
Abstract
We have re-examined the reactivity of the manganese dinitrogen complex [Cp(CO)2 Mn(N2 )] (1, Cp=η5 -cyclopentadienyl, C5 H5 ) with phenylithium (PhLi). By combining experiment and density functional theory (DFT), we have found that, unlike previously reported, the direct nucleophilic attack of the carbanion onto coordinated dinitrogen does not occur. Instead, PhLi reacts with one of the CO ligands to provide an anionic acylcarbonyl dinitrogen metallate [Cp(CO)(N2 )MnCOPh]Li (3) that is stable only below -40 °C. Full characterization of 3 (including single crystal X-ray diffraction) was performed. This complex decomposes quickly above -20 °C with N2 loss to give a phenylate complex [Cp(CO)2 MnPh]Li (2). The latter compound was erroneously formulated as an anionic diazenido compound [Cp(CO)2 MnN(Ph)=N]Li in earlier reports, ruling out the claimed and so-far unique behavior of the N2 ligand in 1. DFT calculations were run to explore both the hypothesized and the experimentally verified reactivity of 1 with PhLi and are fully consistent with our results. Direct attack of a nucleophile on metal-coordinated N2 remains to be demonstrated.
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Affiliation(s)
- Quentin Le Dé
- LCC-CNRS, Université de Toulouse, CNRS, UPS, 205 route de Narbonne, BP44099, 31077, Toulouse cedex 4, France
| | - Amal Bouammali
- LCC-CNRS, Université de Toulouse, CNRS, UPS, 205 route de Narbonne, BP44099, 31077, Toulouse cedex 4, France
| | - Christian Bijani
- LCC-CNRS, Université de Toulouse, CNRS, UPS, 205 route de Narbonne, BP44099, 31077, Toulouse cedex 4, France
| | - Laure Vendier
- LCC-CNRS, Université de Toulouse, CNRS, UPS, 205 route de Narbonne, BP44099, 31077, Toulouse cedex 4, France
| | - Iker Del Rosal
- LPCNO, CNRS & INSA, Université Paul Sabatier, 135 Avenue de Rangueil, 31077, Toulouse, France
| | - Dmitry A Valyaev
- LCC-CNRS, Université de Toulouse, CNRS, UPS, 205 route de Narbonne, BP44099, 31077, Toulouse cedex 4, France
| | - Chiara Dinoi
- LPCNO, CNRS & INSA, Université Paul Sabatier, 135 Avenue de Rangueil, 31077, Toulouse, France
| | - Antoine Simonneau
- LCC-CNRS, Université de Toulouse, CNRS, UPS, 205 route de Narbonne, BP44099, 31077, Toulouse cedex 4, France
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Bhutto SM, Hooper RX, Mercado BQ, Holland PL. Mechanism of Nitrogen-Carbon Bond Formation from Iron(IV) Disilylhydrazido Intermediates during N 2 Reduction. J Am Chem Soc 2023; 145:4626-4637. [PMID: 36794981 DOI: 10.1021/jacs.2c12382] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/17/2023]
Abstract
We recently reported a reaction sequence that activates C-H bonds in simple arenes as well as the N-N triple bond in N2, delivering the aryl group to N2 to form a new N-C bond (Nature 2020, 584, 221). This enables the transformation of abundant feedstocks (arenes and N2) into N-containing organic compounds. The key N-C bond forming step occurs upon partial silylation of N2. However, the pathway through which reduction, silylation, and migration occurred was unknown. Here, we describe synthetic, structural, magnetic, spectroscopic, kinetic, and computational studies that elucidate the steps of this transformation. N2 must be silylated twice at the distal N atom before aryl migration can occur, and sequential silyl radical and silyl cation addition is a kinetically competent pathway to a formally iron(IV)-NN(SiMe3)2 intermediate that can be isolated at low temperature. Kinetic studies show its first-order conversion to the migrated product, and DFT calculations indicate a concerted transition state for migration. The electronic structure of the formally iron(IV) intermediate is examined using DFT and CASSCF calculations, which reveal contributions from iron(II) and iron(III) resonance forms with oxidized NNSi2 ligands. The depletion of electron density from the Fe-coordinated N atom makes it electrophilic enough to accept the incoming aryl group. This new pathway for the N-C bond formation offers a method for functionalizing N2 using organometallic chemistry.
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Affiliation(s)
- Samuel M Bhutto
- Department of Chemistry, Yale University, 225 Prospect St., New Haven, Connecticut 06520, United States
| | - Reagan X Hooper
- Department of Chemistry, Yale University, 225 Prospect St., New Haven, Connecticut 06520, United States
| | - Brandon Q Mercado
- Department of Chemistry, Yale University, 225 Prospect St., New Haven, Connecticut 06520, United States
| | - Patrick L Holland
- Department of Chemistry, Yale University, 225 Prospect St., New Haven, Connecticut 06520, United States
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Bae DY, Lee G, Lee E. Fixation of Dinitrogen at an Asymmetric Binuclear Titanium Complex. Inorg Chem 2021; 60:12813-12822. [PMID: 34492761 DOI: 10.1021/acs.inorgchem.1c01050] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
A new type of dititanium dinitrogen complex supported by a triphenolamine (TPA) ligand is reported. Analysis by single-crystal X-ray diffraction and Raman and NMR spectroscopy reveals different coordination geometries for the two titanium centers. Hence, coordination of TPA and a nitrogen ligand results in trigonal-bipyramidal geometry, while an octahedral titanium center is obtained upon additional coordination of an ethoxide generated upon C-O bond cleavage in a diethyl ether solvent molecule. The titanium complex successfully generates ammonia in the presence of an excess amount of PCy3HI and KC8 in 154% yield (per titanium atom). A titanium complex with a bulkier TPA does not form a dinitrogen complex, and mononuclear titanium dinitrogen complexes were not accessible, presumably because of the high tendency of early transition metals to form binuclear dinitrogen complexes.
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Affiliation(s)
- Dae Young Bae
- Department of Chemistry, Pohang University of Science and Technology (POSTECH), Pohang 37673, Republic of Korea
| | - Gunhee Lee
- Department of Chemistry, Pohang University of Science and Technology (POSTECH), Pohang 37673, Republic of Korea
| | - Eunsung Lee
- Department of Chemistry, Pohang University of Science and Technology (POSTECH), Pohang 37673, Republic of Korea
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