1
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Paschai Darian LK, Ballmann J, Gade LH. T-shaped 14 Electron Rhodium Complexes: Potential Active Species in C-H Activation. Angew Chem Int Ed Engl 2024; 63:e202416814. [PMID: 39545723 DOI: 10.1002/anie.202416814] [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: 09/02/2024] [Revised: 11/12/2024] [Accepted: 11/12/2024] [Indexed: 11/17/2024]
Abstract
Two T-shaped 14-electron rhodium complexes 2 a and 2 b, "framed" and thus stabilized by PNP pincer ligands have been synthesized. The bis(t-butyl)phosphine derived PNPtBu-rhodium complex 2 a was isolated from pentane as the more stable cyclometalated Rh(III) hydrido complex and found to be in equilibrium with the T-shaped 14e- Rh(I) complex 2 aT which itself could be directly crystallized upon change of the solvent. The cyclometallation is suppressed using an adamantyl substituted PNPAd ligand to give the analogous T-shaped Rh(I) species 2 b, stabilized through an agostic interaction with one of the adamantyl C-Hs. Depending on the solvent, complex 2 a reacted with ethylene either by π-coordination (4 a) or C-H activation giving a hydrido-vinyl Rh(III) species 4 b, both isomers being in equilibrium in solution. Complex 2 b was found to reversibly C-H activate arenes to form the hydrido-aryl Rh(III) complexes.
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Affiliation(s)
- Leon K Paschai Darian
- Anorganisch-Chemisches Institut, Universität Heidelberg, Im Neuenheimer Feld 270, 69120, Heidelberg, Germany
| | - Joachim Ballmann
- Anorganisch-Chemisches Institut, Universität Heidelberg, Im Neuenheimer Feld 270, 69120, Heidelberg, Germany
| | - Lutz H Gade
- Anorganisch-Chemisches Institut, Universität Heidelberg, Im Neuenheimer Feld 270, 69120, Heidelberg, Germany
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2
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Braun F, Bruckhoff T, Ott JC, Ballmann J, Gade LH. Carbon-Carbon Bond Activation at Chromium(I): An 11-Electron Complex Cleaving Dialkynes. Angew Chem Int Ed Engl 2024; 63:e202418646. [PMID: 39467298 DOI: 10.1002/anie.202418646] [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: 09/27/2024] [Revised: 10/23/2024] [Accepted: 10/23/2024] [Indexed: 10/30/2024]
Abstract
An 11-electron T-shaped chromium(I) complex was obtained by reduction of a PNP-supported chromium(II) iodide complex. Its d5 high-spin electronic structure was characterized employing paramagnetic NMR, EPR, UV/Vis and magnetic measurements (SQUID). The complex readily reacts with conjugated dialkynes to cleave the internal C-C bond, forming the respective acetylide complexes. Varying the alkyne substituents enabled the isolation and characterization of dinuclear dialkynedichromium intermediates which thermally convert to the products.
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Affiliation(s)
- Felix Braun
- Anorganisch-Chemisches Institut, Ruprecht-Karls-Universität Heidelberg, Im Neuenheimer Feld 276, 69120, Heidelberg, Germany
| | - Tim Bruckhoff
- Anorganisch-Chemisches Institut, Ruprecht-Karls-Universität Heidelberg, Im Neuenheimer Feld 276, 69120, Heidelberg, Germany
| | - Jonas C Ott
- Anorganisch-Chemisches Institut, Ruprecht-Karls-Universität Heidelberg, Im Neuenheimer Feld 276, 69120, Heidelberg, Germany
| | - Joachim Ballmann
- Anorganisch-Chemisches Institut, Ruprecht-Karls-Universität Heidelberg, Im Neuenheimer Feld 276, 69120, Heidelberg, Germany
| | - Lutz H Gade
- Anorganisch-Chemisches Institut, Ruprecht-Karls-Universität Heidelberg, Im Neuenheimer Feld 276, 69120, Heidelberg, Germany
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3
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Sila N, Dürrmann A, Weber B, Heinemann FW, Irrgang T, Kempe R. A Selective Iron(I) Hydrogenation Catalyst. J Am Chem Soc 2024; 146:26877-26883. [PMID: 39308226 DOI: 10.1021/jacs.4c07959] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/03/2024]
Abstract
Iron is the most abundant transition metal of the Earth's crust, and the understanding of its function in key technologies, such as catalysis, is highly important. We report here on an iron(I) hydrogenation catalyst. Our catalyst activates hydrogen via heterolytic bond cleavage, forms a monohydride, and hydrogenates polar double bonds via a bimetallic pathway (potassium-assisted hydride transfer). The mechanism observed seems to exclude oxidative addition and reductive elimination pathways, permitting the tolerance of numerous hydrogenation-sensitive functional groups, as demonstrated for the hydrogenation of C═O bonds.
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Affiliation(s)
- Niko Sila
- Inorganic Chemistry II-Catalyst Design, Sustainable Chemistry Center, University of Bayreuth, 95440 Bayreuth, Germany
| | - Andreas Dürrmann
- Institute for Inorganic and Analytical Chemistry, Friedrich Schiller University Jena, Humboldtstraße 8, 07743 Jena, Germany
| | - Birgit Weber
- Institute for Inorganic and Analytical Chemistry, Friedrich Schiller University Jena, Humboldtstraße 8, 07743 Jena, Germany
| | - Frank W Heinemann
- Department of Chemistry and Pharmacy, Inorganic Chemistry, Friedrich Alexander University Erlangen-Nürnberg, Egerlandstraße 1, 91058 Erlangen, Germany
| | - Torsten Irrgang
- Inorganic Chemistry II-Catalyst Design, Sustainable Chemistry Center, University of Bayreuth, 95440 Bayreuth, Germany
| | - Rhett Kempe
- Inorganic Chemistry II-Catalyst Design, Sustainable Chemistry Center, University of Bayreuth, 95440 Bayreuth, Germany
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4
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Gravogl L, Keilwerth M, Körber E, Heinemann FW, Meyer K. From d 8 to d 1: Iron(0) and Iron(I) Complexes Complete the Series of Eight Fe Oxidation States within the TIMMN Mes Ligand Framework. Inorg Chem 2024; 63:15888-15905. [PMID: 39145894 DOI: 10.1021/acs.inorgchem.4c02129] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/16/2024]
Abstract
Reduction of the ferrous precursor [(TIMMNMes)Fe(Cl)]+ (1) (TIMMNMes = tris-[(3-mesitylimidazol-2-ylidene)methyl]amine) to the low-valent iron(0) complex [(TIMMNMes)Fe(CO)3] (2) is presented, where the tris(N-heterocyclic carbene) (NHC) ligand framework remains intact, yet the coordination mode changed from 3-fold to 2-fold coordination of the carbene arms. Further, the corresponding iron(I) complexes [(TIMMNMes)Fe(L)]+ (L = free site, η1-N2, CO, py) (3) are synthesized and fully characterized. Complexes 1-3 demonstrate the notable steric and electronic flexibility of the TIMMNMes ligand framework by variation of the Fe-N anchor and Fe-carbene distances and the variable size of the axial cavity occupation. This is further underpinned by the oxidation of 3-N2 in a reaction with benzophenone to yield the corresponding, charge-separated iron(II) radical complex [(TIMMNMes)Fe(OCPh2)]+ (4). We found rather surprising similarities in the reactivity behavior when going to low- or high-valent oxidation states of the central iron ion. This is demonstrated by the closely related reactivity of 3-N2, where H atom abstraction with TEMPO triggers the formation of the metallacycle [(TIMMNMes*)Fe(py)]+ (5), and the reactivity of the highly unstable Fe(VII) nitride complex [(TIMMNMes)Fe(N)(F)]3+ to give the metallacyclic Fe(V) imido complex [(TIMMNMesN)Fe(NMes)(MeCN)]3+ (6) upon warming. Thus, the employed tris(carbene) chelate is not only capable of stabilizing the superoxidized Fe(VI) and Fe(VII) nitrides but equally supports the iron center in its low oxidation states 0 and +1. Isolation and characterization of these zero- and monovalent iron complexes demonstrate the extraordinary capability of the tris(carbene) chelate TIMMN to support iron in eight different oxidation states within the very same ligand platform.
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Affiliation(s)
- Lisa Gravogl
- Department of Chemistry and Pharmacy, Inorganic Chemistry, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Egerlandstraße 1, 91058 Erlangen, Germany
| | - Martin Keilwerth
- Department of Chemistry and Pharmacy, Inorganic Chemistry, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Egerlandstraße 1, 91058 Erlangen, Germany
| | - Eva Körber
- Department of Chemistry and Pharmacy, Inorganic Chemistry, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Egerlandstraße 1, 91058 Erlangen, Germany
| | - Frank W Heinemann
- Department of Chemistry and Pharmacy, Inorganic Chemistry, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Egerlandstraße 1, 91058 Erlangen, Germany
| | - Karsten Meyer
- Department of Chemistry and Pharmacy, Inorganic Chemistry, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Egerlandstraße 1, 91058 Erlangen, Germany
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5
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Liu R, Qu Y, Sun Z, Yang L, Xi Z, Dong B, Guo M, Fedushkin IL, Yang XJ. Reduction of Ketones and Coupling of Ketyls by a Zn-Zn-Bonded Compound. Inorg Chem 2024; 63:13558-13567. [PMID: 38962945 DOI: 10.1021/acs.inorgchem.4c01669] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/05/2024]
Abstract
The α-diimine-ligated Zn-Zn-bonded compound [K(THF)2]2[LZn-ZnL] (1, L = [(2,6-iPr2C6H3)NC(Me)]22-) displays diverse reactivities toward a variety of ketones. In the reaction of 1 with benzophenone or 4,4'-di-tert-butylbenzophenone, a multielectron transfer process was observed to give bimetallic (Zn/K) complexes with both ketyl radical fragments and C-C coupled pinacolate moieties (products 2 and 3). In contrast, treating 1 with 9-fluorenone only afforded pinacolate complex 5. Moreover, the reactions of 1 with N- or O-heterocycle-functionalized ketones, i.e., di(2-pyridyl)ketone, 2,2-pyrrolidinone, 9-xanthenone, or 10-methyl-9(10H)-acridone, were also carried out. Besides different transformations of the ketone moiety, the heteroatoms (nitrogen or oxygen) are also involved in coordination with zinc or potassium ions, yielding discrete aggregates or polymeric structures of products 6-9.
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Affiliation(s)
- Rui Liu
- Key Laboratory of Medicinal Molecule Science and Pharmaceutics Engineering, Ministry of Industry and Information Technology, School of Chemistry and Chemical Engineering, Beijing Institute of Technology, Beijing 100081, China
| | - Yao Qu
- Key Laboratory of Medicinal Molecule Science and Pharmaceutics Engineering, Ministry of Industry and Information Technology, School of Chemistry and Chemical Engineering, Beijing Institute of Technology, Beijing 100081, China
| | - Zhenzhou Sun
- Key Laboratory of Medicinal Molecule Science and Pharmaceutics Engineering, Ministry of Industry and Information Technology, School of Chemistry and Chemical Engineering, Beijing Institute of Technology, Beijing 100081, China
| | - Li Yang
- Key Laboratory of Medicinal Molecule Science and Pharmaceutics Engineering, Ministry of Industry and Information Technology, School of Chemistry and Chemical Engineering, Beijing Institute of Technology, Beijing 100081, China
| | - Zhixian Xi
- Key Laboratory of Medicinal Molecule Science and Pharmaceutics Engineering, Ministry of Industry and Information Technology, School of Chemistry and Chemical Engineering, Beijing Institute of Technology, Beijing 100081, China
| | - Ben Dong
- Key Laboratory of Medicinal Molecule Science and Pharmaceutics Engineering, Ministry of Industry and Information Technology, School of Chemistry and Chemical Engineering, Beijing Institute of Technology, Beijing 100081, China
| | - Meng Guo
- Key Laboratory of Medicinal Molecule Science and Pharmaceutics Engineering, Ministry of Industry and Information Technology, School of Chemistry and Chemical Engineering, Beijing Institute of Technology, Beijing 100081, China
| | - Igor L Fedushkin
- G. A. Razuvaev Institute of Organometallic Chemistry of Russian Academy of Sciences (IOMC RAS), Nizhny Novgorod 603950, Russian Federation
| | - Xiao-Juan Yang
- Key Laboratory of Medicinal Molecule Science and Pharmaceutics Engineering, Ministry of Industry and Information Technology, School of Chemistry and Chemical Engineering, Beijing Institute of Technology, Beijing 100081, China
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6
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Bruckhoff T, Ballmann J, Gade LH. Radicalizing CO by Mononuclear Palladium(I). Angew Chem Int Ed Engl 2024; 63:e202320064. [PMID: 38498121 DOI: 10.1002/anie.202320064] [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: 12/26/2023] [Revised: 03/06/2024] [Accepted: 03/12/2024] [Indexed: 03/20/2024]
Abstract
A mononuclear, T-shaped palladium(I) d9 metalloradical (3), stabilized by a bulky carbazole-based PNP-ligand, was obtained by reduction of palladium chloride or thermal Pd-C bond homolysis of the corresponding neopentyl complex. Pressurizing with CO gave the Pd(I) carbonyl complex, which was structurally characterized by X-ray diffraction. Delocalization of the unpaired electron to the carbonyl carbon was detected by EPR spectroscopy and theoretically modeled by DFT and ab initio methods. The partially reduced and radicalized CO slowly reacts with di(tert-butyl) disulfide under homolytic S-S cleavage and C-S bond formation to give the corresponding metallathioester.
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Affiliation(s)
- Tim Bruckhoff
- Anorganisch-Chemisches Institut, Universität Heidelberg, Im Neuenheimer Feld 276, 69120, Heidelberg, Germany
| | - Joachim Ballmann
- Anorganisch-Chemisches Institut, Universität Heidelberg, Im Neuenheimer Feld 276, 69120, Heidelberg, Germany
| | - Lutz H Gade
- Anorganisch-Chemisches Institut, Universität Heidelberg, Im Neuenheimer Feld 276, 69120, Heidelberg, Germany
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7
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Pahar S, Sharma V, Raj KV, Sangole MP, George CP, Singh K, Vanka K, Gonnade RG, Sen SS. Tridentate NacNac Tames T-Shaped Nickel(I) Radical. Chemistry 2024; 30:e202303957. [PMID: 38051591 DOI: 10.1002/chem.202303957] [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: 12/04/2023] [Revised: 12/05/2023] [Accepted: 12/05/2023] [Indexed: 12/07/2023]
Abstract
The reaction of a nickel(II) chloride complex containing a tridentate β-diketiminato ligand with a picolyl group [2,6-iPr2 -C6 H3 NC(Me)CHC(Me)NH(CH2 py)]Ni(II)Cl (1)] with KSi(SiMe3 )3 conveniently afforded a nickel(I) radical with a T-shaped geometry (2). The compound's metalloradical nature was confirmed through electron paramagnetic resonance (EPR) studies and its reaction with TEMPO, resulting in the formation of a highly unusual three-membered nickeloxaziridine complex (3). When reacted with disulfide and diselenide, the S-S and Se-Se bonds were cleaved, and a coupled product was formed through carbon atom of the pyridine-imine group. The nickel(I) radical activates dihydrogen at room temperature and atmospheric pressure to give the monomeric nickel hydride.
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Affiliation(s)
- Sanjukta Pahar
- Inorganic Chemistry and Catalysis Division, CSIR-National Chemical Laboratory, Dr. Homi Bhabha Road, Pashan, Pune, 411008, India
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, 201002, India
| | - Vishal Sharma
- Inorganic Chemistry and Catalysis Division, CSIR-National Chemical Laboratory, Dr. Homi Bhabha Road, Pashan, Pune, 411008, India
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, 201002, India
| | - K Vipin Raj
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, 201002, India
- Physical and Materials Chemistry Division, CSIR-National Chemical Laboratory, Dr. Homi Bhabha Road, Pashan, Pune, 411008, India
| | - Mayur P Sangole
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, 201002, India
- Physical and Materials Chemistry Division, CSIR-National Chemical Laboratory, Dr. Homi Bhabha Road, Pashan, Pune, 411008, India
| | - Christy P George
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, 201002, India
- Physical and Materials Chemistry Division, CSIR-National Chemical Laboratory, Dr. Homi Bhabha Road, Pashan, Pune, 411008, India
| | - Kirandeep Singh
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, 201002, India
- Physical and Materials Chemistry Division, CSIR-National Chemical Laboratory, Dr. Homi Bhabha Road, Pashan, Pune, 411008, India
| | - Kumar Vanka
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, 201002, India
- Physical and Materials Chemistry Division, CSIR-National Chemical Laboratory, Dr. Homi Bhabha Road, Pashan, Pune, 411008, India
| | - Rajesh G Gonnade
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, 201002, India
- Physical and Materials Chemistry Division, CSIR-National Chemical Laboratory, Dr. Homi Bhabha Road, Pashan, Pune, 411008, India
| | - Sakya S Sen
- Inorganic Chemistry and Catalysis Division, CSIR-National Chemical Laboratory, Dr. Homi Bhabha Road, Pashan, Pune, 411008, India
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, 201002, India
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8
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O'Reilly A, Evans MJ, McMullin CL, Fulton JR, Coles MP. Pinacol Cross-Coupling Promoted by an Aluminyl Anion. Chemistry 2024; 30:e202302999. [PMID: 37786922 DOI: 10.1002/chem.202302999] [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: 09/23/2023] [Revised: 09/27/2023] [Accepted: 09/28/2023] [Indexed: 10/04/2023]
Abstract
A simple sequential addition protocol for the reductive coupling of ketones and aldehydes by a potassium aluminyl grants access to unsymmetrical pinacolate derivatives. Isolation of an aluminium ketyl complex presents evidence for the accessibility of radical species. Product release from the aluminium centre was achieved using an iodosilane, forming the disilylated 1,2-diol and a neutral aluminium iodide, thereby demonstrating the steps required to generate a closed synthetic cycle for pinacol (cross) coupling at an aluminyl anion.
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Affiliation(s)
- Andrea O'Reilly
- School of Chemical and Physical Sciences, Victoria University of Wellington, P.O. Box 600, Wellington, 6012, New Zealand
| | - Matthew J Evans
- School of Chemical and Physical Sciences, Victoria University of Wellington, P.O. Box 600, Wellington, 6012, New Zealand
| | | | - J Robin Fulton
- School of Chemical and Physical Sciences, Victoria University of Wellington, P.O. Box 600, Wellington, 6012, New Zealand
| | - Martyn P Coles
- School of Chemical and Physical Sciences, Victoria University of Wellington, P.O. Box 600, Wellington, 6012, New Zealand
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9
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Gajecki L, Sawicka B, Berg DJ, Oliver AG. Synthesis and Magnetic Studies of Two Neutral, Bis-Ligand Fe(II) Complexes Containing Carbazole- Bis(tetrazole) Ligands. Inorg Chem 2023. [PMID: 37478316 DOI: 10.1021/acs.inorgchem.3c01167] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/23/2023]
Abstract
Previously reported carbazole-bis(tetrazole) (CzTR) ligands (where R = iPr and CH2-2,4,6-C6H2Me3) were used to synthesize air-stable, six-coordinate, octahedral bis-ligand Fe(II) complexes (CzTR)2Fe. The synthesis and characterization of these complexes using 1H nuclear magnetic resonance (NMR), X-ray crystallography, Mössbauer spectroscopy, and density functional theory (DFT) calculations are reported. Analysis of the magnetic properties revealed that the isopropyl derivative displays thermally induced spin crossover (SCO) over a temperature range of 150-350 K. This transition appears as an abrupt two-step transition in the solid state but simplifies to a smooth one-step transition in solution. The two-step transition in the solid state has been postulated to be due to lattice and solvation effects. In contrast, the slightly bulkier substituted CH2-2,4,6-C6H2Me3 (CH2Mes) Fe complex displays dramatically different magnetic behavior with no SCO and magnetic data suggesting low-spin Fe(II) with a possible TIP contribution. DFT calculations support the postulate that the change in magnetic behavior is primarily due to the nature of the ligand substituents.
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Affiliation(s)
- Leah Gajecki
- Department of Chemistry, University of Victoria, P.O. Box 3065, Victoria, British Columbia, Canada V8W 3V6
| | - Barbara Sawicka
- Department of Mechanical Engineering, University of Victoria, P.O. Box 1700 STN CSC, Victoria, British Columbia, Canada V8W 2Y2
| | - David J Berg
- Department of Chemistry, University of Victoria, P.O. Box 3065, Victoria, British Columbia, Canada V8W 3V6
| | - Allen G Oliver
- Department of Chemistry & Biochemistry, University of Notre Dame, 251 Nieuwland Science Hall, Notre Dame, Indiana 46556, United States
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10
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Zars E, Gravogl L, Gau MR, Carroll PJ, Meyer K, Mindiola DJ. Isostructural bridging diferrous chalcogenide cores [Fe II(μ-E)Fe II] (E = O, S, Se, Te) with decreasing antiferromagnetic coupling down the chalcogenide series. Chem Sci 2023; 14:6770-6779. [PMID: 37350823 PMCID: PMC10283490 DOI: 10.1039/d3sc01094e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2023] [Accepted: 05/24/2023] [Indexed: 06/24/2023] Open
Abstract
Iron compounds containing a bridging oxo or sulfido moiety are ubiquitous in biological systems, but substitution with the heavier chalcogenides selenium and tellurium, however, is much rarer, with only a few examples reported to date. Here we show that treatment of the ferrous starting material [(tBupyrpyrr2)Fe(OEt2)] (1-OEt2) (tBupyrpyrr2 = 3,5-tBu2-bis(pyrrolyl)pyridine) with phosphine chalcogenide reagents E = PR3 results in the neutral phosphine chalcogenide adduct series [(tBupyrpyrr2)Fe(EPR3)] (E = O, S, Se; R = Ph; E = Te; R = tBu) (1-E) without any electron transfer, whereas treatment of the anionic starting material [K]2[(tBupyrpyrr2)Fe2(μ-N2)] (2-N2) with the appropriate chalcogenide transfer source yields cleanly the isostructural ferrous bridging mono-chalcogenide ate complexes [K]2[(tBupyrpyrr2)Fe2(μ-E)] (2-E) (E = O, S, Se, and Te) having significant deviation in the Fe-E-Fe bridge from linear in the case of E = O to more acute for the heaviest chalcogenide. All bridging chalcogenide complexes were analyzed using a variety of spectroscopic techniques, including 1H NMR, UV-Vis electronic absorbtion, and 57Fe Mössbauer. The spin-state and degree of communication between the two ferrous ions were probed via SQUID magnetometry, where it was found that all iron centers were high-spin (S = 2) FeII, with magnetic exchange coupling between the FeII ions. Magnetic studies established that antiferromagnetic coupling between the ferrous ions decreases as the identity of the chalcogen is tuned from O to the heaviest congener Te.
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Affiliation(s)
- Ethan Zars
- Department of Chemistry, University of Pennsylvania 231 S 34th St Philadelphia PA 19104 USA
| | - Lisa Gravogl
- Department of Chemistry & Pharmacy, Friedrich-Alexander-Universität Erlangen - Nürnberg (FAU) Egerlandstr. 1 91058 Erlangen Bavaria Germany
| | - Michael R Gau
- Department of Chemistry, University of Pennsylvania 231 S 34th St Philadelphia PA 19104 USA
| | - Patrick J Carroll
- Department of Chemistry, University of Pennsylvania 231 S 34th St Philadelphia PA 19104 USA
| | - Karsten Meyer
- Department of Chemistry & Pharmacy, Friedrich-Alexander-Universität Erlangen - Nürnberg (FAU) Egerlandstr. 1 91058 Erlangen Bavaria Germany
| | - Daniel J Mindiola
- Department of Chemistry, University of Pennsylvania 231 S 34th St Philadelphia PA 19104 USA
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12
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Ott JC, Bürgy D, Guan H, Gade LH. 3d Metal Complexes in T-shaped Geometry as a Gateway to Metalloradical Reactivity. Acc Chem Res 2022; 55:857-868. [PMID: 35164502 DOI: 10.1021/acs.accounts.1c00737] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
ConspectusLow-valent, low-coordinate 3d metal complexes represent a class of extraordinarily reactive compounds that can act as reagents and catalysts for challenging bond-activation reactions. The pursuit of these electron-deficient metal complexes in low oxidation states demands ancillary ligands capable of providing not only energetic stabilization but also sufficiently high steric bulk at the metal center. From this perspective, pincer ligands are particularly advantageous, as their prearranged, meridional coordination mode scaffolds the active center while the substituents of the peripheral donor atoms provide effective steric shielding for the coordination sphere. In a T-shaped geometry, the transition metal complexes possess a precisely defined vacant coordination site, which, combined with the often observed high-spin electron configuration, exhibits unusually high selectivity of these compounds with respect to one-electron redox chemistry. In light of the intractable reaction pathways typically observed with related electronically unsaturated 3d transition metal complexes, the pincer coordination mode enables the isolation of low-valent compounds with more controlled and unique reactivity. We have thus investigated a series of T-shaped metal(I) complexes using three different types of pincer ligands, which may be regarded as "metalloradicals" due to their selectively exposed unpaired electrons.These compounds display remarkably high thermal stability and represent rarely observed "naked" monovalent metal species featuring both monomeric and dimeric structures. Extensive reactivity studies using various organic substrates highlight a strong tendency of these paramagnetic compounds to undergo one-electron oxidation, leading to the isolation of a plethora of metal(II) species with reduced organic ligands as unusual structural elements. The exploration of C2 symmetric T-shaped Ni(I) complexes as asymmetric catalysts also shows success in enantioselective hydrodehalogenation of geminal dihalogenides. In addition, this specific class of low-valent, low-coordinate complexes can be further diversified by introducing redox-active pincer ligands or building homobimetallic systems with two T-shaped units.This Account focuses on the discussion of selected examples of iron, cobalt, and nickel pincer complexes bearing a [P,N,P] or [N,N,N] donor set; however, their electronic structure and radical-type reactivity can be broadly extended to other pincer systems. The availability of various types of pincer ligands should allow fine-tuning of the reactivity of the T-shaped complexes. Given the unprecedented reactivity observed with these compounds, we expect the studies of T-shaped 3d metal complexes to be a fertile field for advancing base metal catalysis.
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Affiliation(s)
- Jonas C. Ott
- Anorganisch-Chemisches Institut, Universität Heidelberg, 69120 Heidelberg, Germany
| | - David Bürgy
- Anorganisch-Chemisches Institut, Universität Heidelberg, 69120 Heidelberg, Germany
| | - Hairong Guan
- Department of Chemistry, University of Cincinnati, P.O. Box 210172, Cincinnati, Ohio 45221-0172, United States
| | - Lutz H. Gade
- Anorganisch-Chemisches Institut, Universität Heidelberg, 69120 Heidelberg, Germany
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13
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Sieg G, Pessemesse Q, Reith S, Yelin S, Limberg C, Munz D, Werncke CG. Cobalt and Iron Stabilized Ketyl, Ketiminyl and Aldiminyl Radical Anions. Chemistry 2021; 27:16760-16767. [PMID: 34569676 PMCID: PMC9298351 DOI: 10.1002/chem.202103096] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2021] [Indexed: 01/02/2023]
Abstract
Carbonyl and iminyl based radical anions are reactive intermediates in a variety of transformations in organic synthesis. Herein, the isolation of ketyl, and more importantly unprecedented ketiminyl and aldiminyl radical anions coordinated to cobalt and iron complexes is presented. Insights into the electronic structure of these unusual metal bound radical anions is provided by X-Ray diffraction analysis, NMR, IR, UV/Vis and Mössbauer spectroscopy, solid and solution state magnetometry, as well as a by a detailed computational analysis. The metal bound radical anions are very reactive and facilitate the activation of intra- and intermolecular C-H bonds.
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Affiliation(s)
- Grégoire Sieg
- Fachbereich ChemiePhilipps-Universität MarburgHans-Meerwein-Straße 435043MarburgGermany
| | - Quentin Pessemesse
- Univ. Lyon, ENS de Lyon, CNRS UMR 5182 Université Claude Bernard Lyon 1, Laboratoire de Chimie69342LyonFrance
- Anorganische Chemie: Koordinationschemie Campus C4.1Universität des Saarlandes66123SaarbrückenGermany
| | - Sascha Reith
- Fachbereich ChemiePhilipps-Universität MarburgHans-Meerwein-Straße 435043MarburgGermany
| | - Stefan Yelin
- Institut für ChemieHumboldt-Universität zu BerlinBrook-Taylor-Str. 212489BerlinGermany
| | - Christian Limberg
- Institut für ChemieHumboldt-Universität zu BerlinBrook-Taylor-Str. 212489BerlinGermany
| | - Dominik Munz
- Anorganische Chemie: Koordinationschemie Campus C4.1Universität des Saarlandes66123SaarbrückenGermany
- Department Chemie und PharmazieFriedrich-Alexander Universität (FAU) Erlangen-NürnbergEgerlandstr. 1D-91058ErlangenGermany
| | - C. Gunnar Werncke
- Fachbereich ChemiePhilipps-Universität MarburgHans-Meerwein-Straße 435043MarburgGermany
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14
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Watt FA, Sieland B, Dickmann N, Schoch R, Herbst-Irmer R, Ott H, Paradies J, Kuckling D, Hohloch S. Coupling of CO 2 and epoxides catalysed by novel N-fused mesoionic carbene complexes of nickel(II). Dalton Trans 2021; 50:17361-17371. [PMID: 34788774 DOI: 10.1039/d1dt03311e] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We report the syntheses of two rigid mesoionic carbene (MIC) ligands with a carbazole backbone via an intramolecular Finkelstein-cyclisation cascade and investigate their coordination behavior towards nickel(II) acetate. Despite the nickel(II) carbene complexes 4a,b showing only minor differences in their chemical composition, they display curious differences in their chemical properties, e.g. solubility. Furthermore, the potential of these novel MIC complexes in the coupling of carbon dioxide and epoxides as well as the differences in reactivity compared to classical NHC-derived complexes are evaluated.
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Affiliation(s)
- Fabian A Watt
- Paderborn University, Faculty of Science, Department of Chemistry, Warburger Straße 100, 33098 Paderborn, Germany
| | - Benedikt Sieland
- Paderborn University, Faculty of Science, Department of Chemistry, Warburger Straße 100, 33098 Paderborn, Germany
| | - Nicole Dickmann
- Paderborn University, Faculty of Science, Department of Chemistry, Warburger Straße 100, 33098 Paderborn, Germany
| | - Roland Schoch
- Paderborn University, Faculty of Science, Department of Chemistry, Warburger Straße 100, 33098 Paderborn, Germany
| | - Regine Herbst-Irmer
- University of Göttingen, Institute of Inorganic Chemistry, Tammannstraße 4, 37077 Göttingen, Germany
| | - Holger Ott
- Bruker AXS GmbH, Östliche Rheinbrückenstraße 49, 76187 Karlsruhe, Germany
| | - Jan Paradies
- Paderborn University, Faculty of Science, Department of Chemistry, Warburger Straße 100, 33098 Paderborn, Germany
| | - Dirk Kuckling
- Paderborn University, Faculty of Science, Department of Chemistry, Warburger Straße 100, 33098 Paderborn, Germany
| | - Stephan Hohloch
- University of Innsbruck, Faculty of Chemistry and Pharmacy, Institute of General, Inorganic and Theoretical Chemistry, Innrain 80-82, 6020 Innsbruck, Austria.
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15
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Li Y, Lin X, Ma F, Mo Y. Computational Study of CO 2 Reduction Catalyzed by Iron(I) Complex at Different Spin States: Cooperativity of Hydrogen Bonding and Auxiliary Group Effect. ACS OMEGA 2021; 6:31971-31981. [PMID: 34870020 PMCID: PMC8637949 DOI: 10.1021/acsomega.1c04758] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/30/2021] [Accepted: 11/02/2021] [Indexed: 06/13/2023]
Abstract
To explore alternative approaches to the CO2 reduction to formate and provide an insight into the spin state effect on the CO2 reduction, we theoretically designed a kind of low-valence iron(I) model complex, whose doublet, quartet, and sextet states are denoted as 2 Fe(I), 4 Fe(I), and 6 Fe(I), respectively. This complex is featured with an iron(I) center, which bonds to a 1,2-ethanediamine (en) and a 2-hydroxy-biphenyl group. Reaction mechanisms for the CO2 reduction to formate catalyzed by this iron(I) model complex were explored using density functional theory (DFT) computations. Studies showed that the univalent iron(I) compound can efficiently fix and activate a CO2 molecule, whereas its oxidized forms with trivalent iron(III) or bivalent iron(II) cannot activate CO2. For the iron(I) compound, it was found that the lowest spin state 2 Fe(I) is the most favorable for the CO2 reduction as the reactions barriers involving 2 Fe(I), 4 Fe(I), and 6 Fe(I) are 25.6, 37.2, and 35.9 kcal/mol, respectively. Yet, a photosensitizer-free visible-light-mediated high-low spin shift from 4 Fe(I) and 6 Fe(I) to 2 Fe(I) is likely through the reverse intersystem crossing (RIC) because the 4 Fe(I) and 6 Fe(I) compounds have strong absorption in the visible-light range. Notably, the synergistic interaction between the hydrogen bonding from the auxiliary hydroxyl group in the 2-hydroxy-biphenyl moiety to CO2 and an intermediate five-membered ring promotes the proton transfer, leading to the formation of the -COOH moiety from CO2 and the Fe-O bond. With the addition of H2, one H2 molecule is split by the Fe-O bond and thus serves as H atom sources for both the CO2 reduction and the recovery of the auxiliary hydroxyl group. The present theoretical study provides a novel solution for the challenging CO2 reduction, which calls for further experimental verifications.
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Affiliation(s)
- Yazhou Li
- School
of Chemistry and Materials Science, Huaibei
Normal University, Huaibei 235000, China
| | - Xuhui Lin
- Sichuan
Engineering Research Center for Biomimetic Synthesis of Natural Drugs,
School of Life Science and Engineering, Southwest Jiaotong University, Chengdu 610031, China
| | - Fang Ma
- School
of Chemistry and Materials Science, Huaibei
Normal University, Huaibei 235000, China
| | - Yirong Mo
- Department
of Nanoscience, Joint School of Nanoscience and Nanoengineering, University of North Carolina at Greensboro, Greensboro, North Carolina 27401, United States
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16
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Ott JC, Suturina EA, Kuprov I, Nehrkorn J, Schnegg A, Enders M, Gade LH. Observability of Paramagnetic NMR Signals at over 10 000 ppm Chemical Shifts. Angew Chem Int Ed Engl 2021; 60:22856-22864. [PMID: 34351041 PMCID: PMC8518043 DOI: 10.1002/anie.202107944] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2021] [Indexed: 12/27/2022]
Abstract
We report an experimental observation of 31 P NMR resonances shifted by over 10 000 ppm (meaning percent range, and a new record for solutions), and similar 1 H chemical shifts, in an intermediate-spin square planar ferrous complex [tBu (PNP)Fe-H], where PNP is a carbazole-based pincer ligand. Using a combination of electronic structure theory, nuclear magnetic resonance, magnetometry, and terahertz electron paramagnetic resonance, the influence of magnetic anisotropy and zero-field splitting on the paramagnetic shift and relaxation enhancement is investigated. Detailed spin dynamics simulations indicate that, even with relatively slow electron spin relaxation (T1 ≈10-11 s), it remains possible to observe NMR signals of directly metal-bonded atoms because pronounced rhombicity in the electron zero-field splitting reduces nuclear paramagnetic relaxation enhancement.
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Affiliation(s)
- Jonas C. Ott
- Anorganisch-Chemisches InstitutUniversität HeidelbergIm Neuenheimer Feld 27669120HeidelbergGermany
| | | | - Ilya Kuprov
- School of ChemistryUniversity of SouthamptonSouthamptonSO17 1BJUK
| | - Joscha Nehrkorn
- EPR Research GroupMPI for Chemical Energy ConversionStiftstrasse 34–3645470Mülheim RuhrGermany
| | - Alexander Schnegg
- EPR Research GroupMPI for Chemical Energy ConversionStiftstrasse 34–3645470Mülheim RuhrGermany
| | - Markus Enders
- Anorganisch-Chemisches InstitutUniversität HeidelbergIm Neuenheimer Feld 27669120HeidelbergGermany
| | - Lutz H. Gade
- Anorganisch-Chemisches InstitutUniversität HeidelbergIm Neuenheimer Feld 27669120HeidelbergGermany
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17
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Ott JC, Suturina EA, Kuprov I, Nehrkorn J, Schnegg A, Enders M, Gade LH. Observability of Paramagnetic NMR Signals at over 10 000 ppm Chemical Shifts. Angew Chem Int Ed Engl 2021. [DOI: 10.1002/ange.202107944] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Jonas C. Ott
- Anorganisch-Chemisches Institut Universität Heidelberg Im Neuenheimer Feld 276 69120 Heidelberg Germany
| | | | - Ilya Kuprov
- School of Chemistry University of Southampton Southampton SO17 1BJ UK
| | - Joscha Nehrkorn
- EPR Research Group MPI for Chemical Energy Conversion Stiftstrasse 34–36 45470 Mülheim Ruhr Germany
| | - Alexander Schnegg
- EPR Research Group MPI for Chemical Energy Conversion Stiftstrasse 34–36 45470 Mülheim Ruhr Germany
| | - Markus Enders
- Anorganisch-Chemisches Institut Universität Heidelberg Im Neuenheimer Feld 276 69120 Heidelberg Germany
| | - Lutz H. Gade
- Anorganisch-Chemisches Institut Universität Heidelberg Im Neuenheimer Feld 276 69120 Heidelberg Germany
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18
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Babak MV, Chong KR, Rapta P, Zannikou M, Tang HM, Reichert L, Chang MR, Kushnarev V, Heffeter P, Meier‐Menches SM, Lim ZC, Yap JY, Casini A, Balyasnikova IV, Ang WH. Interfering with Metabolic Profile of Triple‐Negative Breast Cancers Using Rationally Designed Metformin Prodrugs. Angew Chem Int Ed Engl 2021. [DOI: 10.1002/ange.202102266] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- Maria V. Babak
- Drug Discovery Lab Department of Chemistry City University of Hong Kong 83 Tat Chee Avenue 999077 Hong Kong SAR P. R. China
| | - Kai Ren Chong
- Department of Chemistry National University of Singapore 3 Science Drive 2 117543 Singapore Singapore
| | - Peter Rapta
- Institute of Physical Chemistry and Chemistry Physics Slovak Technical University of Technology Radlinského 9 82137 Bratislava Slovak Republic
| | - Markella Zannikou
- Department of Neurological Surgery The Feinberg School of Medicine Northwestern University Chicago IL 60611 USA
| | - Hui Min Tang
- Department of Chemistry National University of Singapore 3 Science Drive 2 117543 Singapore Singapore
| | - Lisa Reichert
- Department of Chemistry National University of Singapore 3 Science Drive 2 117543 Singapore Singapore
| | - Meng Rui Chang
- Department of Chemistry National University of Singapore 3 Science Drive 2 117543 Singapore Singapore
| | - Vladimir Kushnarev
- FSBI “National Medical Research Center of Oncology, named after N.N Petrov” Ministry of Healthcare of the Russian Federation 68 Leningradskaya Street, Pesochny 197758 St Petersburg Russian Federation
| | - Petra Heffeter
- Institute of Cancer Research and Comprehensive Cancer Center Department of Medicine I Medical University of Vienna Borschkegasse 8a 1090 Vienna Austria
| | | | - Zhi Chiaw Lim
- Department of Chemistry National University of Singapore 3 Science Drive 2 117543 Singapore Singapore
| | - Jian Yu Yap
- Department of Chemistry National University of Singapore 3 Science Drive 2 117543 Singapore Singapore
| | - Angela Casini
- Department of Chemistry Technical University of Munich Lichtenbergstr. 4 85748 Garching, München Germany
| | - Irina V. Balyasnikova
- Department of Neurological Surgery The Feinberg School of Medicine Northwestern University Chicago IL 60611 USA
| | - Wee Han Ang
- Department of Chemistry National University of Singapore 3 Science Drive 2 117543 Singapore Singapore
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19
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Babak MV, Chong KR, Rapta P, Zannikou M, Tang HM, Reichert L, Chang MR, Kushnarev V, Heffeter P, Meier-Menches SM, Lim ZC, Yap JY, Casini A, Balyasnikova IV, Ang WH. Interfering with Metabolic Profile of Triple-Negative Breast Cancers Using Rationally Designed Metformin Prodrugs. Angew Chem Int Ed Engl 2021; 60:13405-13413. [PMID: 33755286 DOI: 10.1002/anie.202102266] [Citation(s) in RCA: 31] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2021] [Indexed: 12/19/2022]
Abstract
Triple-negative breast cancer (TNBC) is the most aggressive subtype of breast cancer, characterized by an aberrant metabolic phenotype with high metastatic capacity, resulting in poor patient prognoses and low survival rates. We designed a series of novel AuIII cyclometalated prodrugs of energy-disrupting Type II antidiabetic drugs namely, metformin and phenformin. Prodrug activation and release of the metformin ligand was achieved by tuning the cyclometalated AuIII fragment. The lead complex 3met was 6000-fold more cytotoxic compared to uncoordinated metformin and significantly reduced tumor burden in mice with aggressive breast cancers with lymphocytic infiltration into tumor tissues. These effects was ascribed to 3met interfering with energy production in TNBCs and inhibiting associated pro-survival responses to induce deadly metabolic catastrophe.
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Affiliation(s)
- Maria V Babak
- Drug Discovery Lab, Department of Chemistry, City University of Hong Kong, 83 Tat Chee Avenue, 999077, Hong Kong SAR, P. R. China
| | - Kai Ren Chong
- Department of Chemistry, National University of Singapore, 3 Science Drive 2, 117543, Singapore, Singapore
| | - Peter Rapta
- Institute of Physical Chemistry and Chemistry Physics, Slovak Technical University of Technology, Radlinského 9, 82137, Bratislava, Slovak Republic
| | - Markella Zannikou
- Department of Neurological Surgery, The Feinberg School of Medicine, Northwestern University, Chicago, IL, 60611, USA
| | - Hui Min Tang
- Department of Chemistry, National University of Singapore, 3 Science Drive 2, 117543, Singapore, Singapore
| | - Lisa Reichert
- Department of Chemistry, National University of Singapore, 3 Science Drive 2, 117543, Singapore, Singapore
| | - Meng Rui Chang
- Department of Chemistry, National University of Singapore, 3 Science Drive 2, 117543, Singapore, Singapore
| | - Vladimir Kushnarev
- FSBI "National Medical Research Center of Oncology, named after N.N Petrov", Ministry of Healthcare of the Russian Federation, 68 Leningradskaya Street, Pesochny, 197758, St Petersburg, Russian Federation
| | - Petra Heffeter
- Institute of Cancer Research and Comprehensive Cancer Center, Department of Medicine I, Medical University of Vienna, Borschkegasse 8a, 1090, Vienna, Austria
| | - Samuel M Meier-Menches
- Department of Analytical Chemistry, Faculty of Chemistry, University of Vienna, Vienna, Austria
| | - Zhi Chiaw Lim
- Department of Chemistry, National University of Singapore, 3 Science Drive 2, 117543, Singapore, Singapore
| | - Jian Yu Yap
- Department of Chemistry, National University of Singapore, 3 Science Drive 2, 117543, Singapore, Singapore
| | - Angela Casini
- Department of Chemistry, Technical University of Munich, Lichtenbergstr. 4, 85748, Garching, München, Germany
| | - Irina V Balyasnikova
- Department of Neurological Surgery, The Feinberg School of Medicine, Northwestern University, Chicago, IL, 60611, USA
| | - Wee Han Ang
- Department of Chemistry, National University of Singapore, 3 Science Drive 2, 117543, Singapore, Singapore
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20
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Sharma MK, Rottschäfer D, Neumann B, Stammler HG, Danés S, Andrada DM, van Gastel M, Hinz A, Ghadwal RS. Metalloradical Cations and Dications Based on Divinyldiphosphene and Divinyldiarsene Ligands. Chemistry 2021; 27:5803-5809. [PMID: 33470468 PMCID: PMC8048781 DOI: 10.1002/chem.202100213] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2021] [Indexed: 01/09/2023]
Abstract
Metalloradicals are key species in synthesis, catalysis, and bioinorganic chemistry. Herein, two iron radical cation complexes (3‐E)GaCl4 [(3‐E).+ = [{(IPr)C(Ph)E}2Fe(CO)3].+, E = P or As; IPr = C{(NDipp)CH}2, Dipp = 2,6‐iPr2C6H3] are reported as crystalline solids. Treatment of the divinyldipnictenes {(IPr)C(Ph)E}2 (1‐E) with Fe2(CO)9 affords [{(IPr)C(Ph)E}2Fe(CO)3] (2‐E), in which 1‐E binds to the Fe atom in an allylic (η3‐EECvinyl) fashion and functions as a 4e donor ligand. Complexes 2‐E undergo 1e oxidation with GaCl3 to yield (3‐E)GaCl4. Spin density analysis revealed that the unpaired electron in (3‐E).+ is mainly located on the Fe (52–64 %) and vinylic C (30–36 %) atoms. Further 1e oxidation of (3‐E)GaCl4 leads to unprecedented η3‐EECvinyl to η3‐ECvinylCPh coordination shuttling to form the dications (4‐E)(GaCl4)2.
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Affiliation(s)
- Mahendra K Sharma
- Molecular Inorganic Chemistry and Catalysis, Inorganic and Structural Chemistry, Center for Molecular Materials, Faculty of Chemistry, Universität Bielefeld, Universitätsstrasse 25, 33615, Bielefeld, Germany
| | - Dennis Rottschäfer
- Molecular Inorganic Chemistry and Catalysis, Inorganic and Structural Chemistry, Center for Molecular Materials, Faculty of Chemistry, Universität Bielefeld, Universitätsstrasse 25, 33615, Bielefeld, Germany
| | - Beate Neumann
- Molecular Inorganic Chemistry and Catalysis, Inorganic and Structural Chemistry, Center for Molecular Materials, Faculty of Chemistry, Universität Bielefeld, Universitätsstrasse 25, 33615, Bielefeld, Germany
| | - Hans-Georg Stammler
- Molecular Inorganic Chemistry and Catalysis, Inorganic and Structural Chemistry, Center for Molecular Materials, Faculty of Chemistry, Universität Bielefeld, Universitätsstrasse 25, 33615, Bielefeld, Germany
| | - Sergi Danés
- Allgemeine und Anorganische Chemie, Universität des Saarlandes, Campus C4.1, 66123, Saarbrücken, Germany
| | - Diego M Andrada
- Allgemeine und Anorganische Chemie, Universität des Saarlandes, Campus C4.1, 66123, Saarbrücken, Germany
| | - Maurice van Gastel
- Max-Planck-Institut für Kohlenforschung Molecular Theory and Spectroscopy, Kaiser-Wilhelm-Platz 1, Mülheim an der Ruhr, 45470, Germany
| | - Alexander Hinz
- Institute of Inorganic Chemistry, Karlsruhe Institute of Technology (KIT), Engesserstrasse 15, 76131, Karlsruhe, Germany
| | - Rajendra S Ghadwal
- Molecular Inorganic Chemistry and Catalysis, Inorganic and Structural Chemistry, Center for Molecular Materials, Faculty of Chemistry, Universität Bielefeld, Universitätsstrasse 25, 33615, Bielefeld, Germany
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21
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Ott JC, Wadepohl H, Gade LH. Metalloradical Reactivity, Charge Transfer, and Atom Abstractions in a T-Shaped Iron(I) Complex. Inorg Chem 2021; 60:3927-3938. [DOI: 10.1021/acs.inorgchem.0c03724] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Affiliation(s)
- Jonas C. Ott
- Anorganisch-Chemisches Institut, Universität Heidelberg, Im Neuenheimer Feld 276, 69120 Heidelberg, Germany
| | - Hubert Wadepohl
- Anorganisch-Chemisches Institut, Universität Heidelberg, Im Neuenheimer Feld 276, 69120 Heidelberg, Germany
| | - Lutz H. Gade
- Anorganisch-Chemisches Institut, Universität Heidelberg, Im Neuenheimer Feld 276, 69120 Heidelberg, Germany
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22
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Ott JC, Isak D, Melder JJ, Wadepohl H, Gade LH. Single or Paired? Structure and Reactivity of PNP-Chromium(II) Hydrides. Inorg Chem 2020; 59:14526-14535. [PMID: 32931701 DOI: 10.1021/acs.inorgchem.0c02315] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The preparation and reactivity of a range of novel paramagnetic chromium(II) complexes supported by a carbazole-based PNP pincer ligand is reported. Deprotonation of the ligand precursors R(PNP)H (1R) and subsequent reaction with chromium(II) chloride led to the formation of square-planar chlorido complexes R(PNP)CrCl (2R). Further reaction with various alkylating agents resulted in the isolation of chromium alkyl complexes R(PNP)CrR' (3R-R') which were then hydrogenated to yield two rare examples of paramagnetic chromium(II) hydrides 4iPr and 4tBu. Both compounds were characterized by X-ray diffraction and paramagnetic NMR spectroscopy supported by a comprehensive DFT-supported assignment of the resonances. While the di(tert-butyl)phosphino PNP substituted complex 4tBu was found to exhibit a monomeric square-planar molecular structure, its isopropyl-substituted analog 4iPr forms a dimer, also indicated by a strong antiferromagnetic coupling of the chromium centers. The pronounced reactivity of these compounds toward C═X double bonds was demonstrated by reaction with benzophenone, N,N'-dicyclohexylcarbodiimide, and carbon dioxide, which gave the corresponding insertion products. The alkoxido complex 5iPr, the amidinato complex 6iPr, and the formato compound 7tBu were also characterized by X-ray diffraction.
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Affiliation(s)
- Jonas C Ott
- Anorganisch-Chemisches Institut, Universität Heidelberg, Im Neuenheimer Feld 276, 69120 Heidelberg, Germany
| | - Daniel Isak
- Anorganisch-Chemisches Institut, Universität Heidelberg, Im Neuenheimer Feld 276, 69120 Heidelberg, Germany
| | - Julian J Melder
- Anorganisch-Chemisches Institut, Universität Heidelberg, Im Neuenheimer Feld 276, 69120 Heidelberg, Germany
| | - Hubert Wadepohl
- Anorganisch-Chemisches Institut, Universität Heidelberg, Im Neuenheimer Feld 276, 69120 Heidelberg, Germany
| | - Lutz H Gade
- Anorganisch-Chemisches Institut, Universität Heidelberg, Im Neuenheimer Feld 276, 69120 Heidelberg, Germany
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23
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Ott JC, Wadepohl H, Gade LH. Opening up the Valence Shell: A T-Shaped Iron(I) Metalloradical and Its Potential for Atom Abstraction. Angew Chem Int Ed Engl 2020; 59:9448-9452. [PMID: 32196900 PMCID: PMC7318345 DOI: 10.1002/anie.202003118] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2020] [Indexed: 11/06/2022]
Abstract
A thermally stable, T-shaped, d7 high-spin iron(I) complex was obtained by reduction of a PNP-supported ferrous chloride. Paramagnetic NMR spectroscopy combined with DFT modeling was used to analyze the electronic structure of the coordinatively highly unsaturated complex. The metalloradical character of the compound was demonstrated by the formation of a benzophenone ketyl radical complex upon addition of benzophenone. Furthermore, the compound displays a rich chemistry as an oxygen-atom abstractor from epoxides, yielding a dinuclear, diferrous [Fe2 O] complex.
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Affiliation(s)
- Jonas C. Ott
- Anorganisch-Chemisches InstitutUniversität HeidelbergIm Neuenheimer Feld 27669120HeidelbergGermany
| | - Hubert Wadepohl
- Anorganisch-Chemisches InstitutUniversität HeidelbergIm Neuenheimer Feld 27669120HeidelbergGermany
| | - Lutz H. Gade
- Anorganisch-Chemisches InstitutUniversität HeidelbergIm Neuenheimer Feld 27669120HeidelbergGermany
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