1
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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. [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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2
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Landaeta VR, Horsley Downie TM, Wolf R. Low-Valent Transition Metalate Anions in Synthesis, Small Molecule Activation, and Catalysis. Chem Rev 2024; 124:1323-1463. [PMID: 38354371 PMCID: PMC10906008 DOI: 10.1021/acs.chemrev.3c00121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2023] [Revised: 10/09/2023] [Accepted: 10/09/2023] [Indexed: 02/16/2024]
Abstract
This review surveys the synthesis and reactivity of low-oxidation state metalate anions of the d-block elements, with an emphasis on contributions reported between 2006 and 2022. Although the field has a long and rich history, the chemistry of transition metalate anions has been greatly enhanced in the last 15 years by the application of advanced concepts in complex synthesis and ligand design. In recent years, the potential of highly reactive metalate complexes in the fields of small molecule activation and homogeneous catalysis has become increasingly evident. Consequently, exciting applications in small molecule activation have been developed, including in catalytic transformations. This article intends to guide the reader through the fascinating world of low-valent transition metalates. The first part of the review describes the synthesis and reactivity of d-block metalates stabilized by an assortment of ligand frameworks, including carbonyls, isocyanides, alkenes and polyarenes, phosphines and phosphorus heterocycles, amides, and redox-active nitrogen-based ligands. Thereby, the reader will be familiarized with the impact of different ligand types on the physical and chemical properties of metalates. In addition, ion-pairing interactions and metal-metal bonding may have a dramatic influence on metalate structures and reactivities. The complex ramifications of these effects are examined in a separate section. The second part of the review is devoted to the reactivity of the metalates toward small inorganic molecules such as H2, N2, CO, CO2, P4 and related species. It is shown that the use of highly electron-rich and reactive metalates in small molecule activation translates into impressive catalytic properties in the hydrogenation of organic molecules and the reduction of N2, CO, and CO2. The results discussed in this review illustrate that the potential of transition metalate anions is increasingly being tapped for challenging catalytic processes with relevance to organic synthesis and energy conversion. Therefore, it is hoped that this review will serve as a useful resource to inspire further developments in this dynamic research field.
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Affiliation(s)
| | | | - Robert Wolf
- University of Regensburg, Institute
of Inorganic Chemistry, 93040 Regensburg, Germany
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3
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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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4
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Segizbayev M, Tho Nguyen M, Gusev DG, Dmitrienko A, Pilkington M, van der Est A, Nikonov GI. A Guanidine-Supported π-Complex of Germanium Amenable to Intramolecular C-C Cleavage in Arene and Ge Atom Transfer. Chemistry 2023; 29:e202301981. [PMID: 37732936 DOI: 10.1002/chem.202301981] [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: 08/17/2023] [Revised: 09/20/2023] [Accepted: 09/21/2023] [Indexed: 09/22/2023]
Abstract
The germylone dimNHCGe (dimNHC=diimino N-heterocyclic carbene) reacts with azides N3 R (R=SiMe3 or p-tolyl) to furnish the first examples of germanium π-complexes, i. e. guanidine-ligated compounds (dimNHI-SiMe3 )Ge (NHI=N-heterocyclic imine, R=SiMe3 ) and (dimNHI-Tol)Ge (R=p-tolyl). DFT calculations suggest that these species are formed by a Staudinger type replacement of dinitrogen in the azide by a nucleophilic germylone, leading to a transient carbene adduct of iminogermylidene. Heating a solution of compound (dimNHI-SiMe3 )Ge to 70 °C results in extrusion of the iminogermylidene that further aggregates to produce the known [Me3 SiNGe]4 tetramer, whereas the imidazolylidene fragment transforms into an unusual heptatriene species that can be considered as a product of carbene insertion into the C-C bond of a pendant Ar substituent at the imidazolylidene nitrogen of the dimNHC. Reaction of (dimNHI-SiMe3 )Ge with tetrachloro-o-benzoquinone results in the net transfer of a germanium atom and formation of the free diimino-guanidine ligand. This ligand also forms when (dimNHI-SiMe3 )Ge is treated with azide N3 (p-Tol), with the germanium product being [(p-Tol)NGe]n.
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Affiliation(s)
- Medet Segizbayev
- Department of Chemistry, Brock University, 1812 Sir Isaac Brock Way, St. Catharines, Ontario L2S 3A1, Canada
| | - Minh Tho Nguyen
- Department of Chemistry, Brock University, 1812 Sir Isaac Brock Way, St. Catharines, Ontario L2S 3A1, Canada
| | - Dmitry G Gusev
- Department of Chemistry and Biochemistry, Wilfrid Laurier University, 75 University Ave W, Waterloo, Ontario N2 L 3 C5, Canada
| | - Anton Dmitrienko
- Department of Chemistry, Brock University, 1812 Sir Isaac Brock Way, St. Catharines, Ontario L2S 3A1, Canada
| | - Melanie Pilkington
- Department of Chemistry, Brock University, 1812 Sir Isaac Brock Way, St. Catharines, Ontario L2S 3A1, Canada
| | - Art van der Est
- Department of Chemistry, Brock University, 1812 Sir Isaac Brock Way, St. Catharines, Ontario L2S 3A1, Canada
| | - Georgii I Nikonov
- Department of Chemistry, Brock University, 1812 Sir Isaac Brock Way, St. Catharines, Ontario L2S 3A1, Canada
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5
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Gonzalez A, Demeshko S, Meyer F, Werncke CG. A low-coordinate iron organoazide complex. Chem Commun (Camb) 2023; 59:11532-11535. [PMID: 37672291 DOI: 10.1039/d3cc03765g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/07/2023]
Abstract
A labile organoazide iron complex is reported. Under ambient conditions, the azide adduct is subject to a dissociation equilibrium in solution, yet also undergoes intramolecular C-H bond amination. Single-crystal irradiation of the azide at 80 K leads to partial N2-extrusion and formation of a putative imido iron intermediate, which was computationally identified as a highly covalent {FeNR}8 species.
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Affiliation(s)
- Andres Gonzalez
- Philipps-University Marburg, Hans-Meerwein-Straße 4, Marburg D-35032, Germany.
| | - Serhiy Demeshko
- Institute of Inorganic Chemistry, University of Göttingen, Tammannstr. 4, Göttingen D-37077, Germany
| | - Franc Meyer
- Institute of Inorganic Chemistry, University of Göttingen, Tammannstr. 4, Göttingen D-37077, Germany
| | - C Gunnar Werncke
- Philipps-University Marburg, Hans-Meerwein-Straße 4, Marburg D-35032, Germany.
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6
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Hertler PR, Lewis RA, Wu G, Hayton TW. Measuring Metal-Metal Communication in a Series of Ketimide-Bridged [Fe 2] 6+ Complexes. Inorg Chem 2023; 62:11829-11836. [PMID: 37462407 DOI: 10.1021/acs.inorgchem.3c01109] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/01/2023]
Abstract
Reaction of Fe(acac)3 with 3 equiv of Li[N═C(R)Ph] (R = Ph, tBu) results in the formation of the [Fe2]6+ complexes, [Fe2(μ-N═C(R)Ph)2(N═C(R)Ph)4] (R = Ph, 1; tBu, 2), in low to moderate yields. Reaction of FeCl2 with 6 equiv of Li(N═C13H8) (HN═C13H8 = 9-fluorenone imine) results in the formation of [Li(THF)2]2[Fe(N═C13H8)4] (3) in good yield. Subsequent oxidation of 3 with ca. 0.8 equiv of I2 generates the [Fe2]6+ complex, [Fe2(μ-N═C13H8)2(N═C13H8)4] (4), along with free fluorenyl ketazine. Complexes 1, 2, and 4 were characterized by 1H NMR spectroscopy, X-ray crystallography, 57Fe Mössbauer spectroscopy, and SQUID magnetometry. The Fe-Fe distances in 1, 2, and 4 range from 2.803(7) to 2.925(1) Å, indicating that no direct Fe-Fe interaction is present in these complexes. The 57Fe Mössbauer spectra for complexes 1, 2, and 4 are all consistent with the presence of symmetry-equivalent high-spin Fe3+ centers. Finally, all three complexes exhibit a similar degree of antiferromagnetic coupling between the metal centers (J = -26 to -30 cm-1), as ascertained by SQUID magnetometry.
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Affiliation(s)
- Phoebe R Hertler
- Department of Chemistry and Biochemistry, University of California Santa Barbara, Santa Barbara, California 93106, United States
| | - Richard A Lewis
- Department of Chemistry and Biochemistry, University of California Santa Barbara, Santa Barbara, California 93106, United States
| | - Guang Wu
- Department of Chemistry and Biochemistry, University of California Santa Barbara, Santa Barbara, California 93106, United States
| | - Trevor W Hayton
- Department of Chemistry and Biochemistry, University of California Santa Barbara, Santa Barbara, California 93106, United States
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7
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Gonzalez A, Chen TY, Demeshko S, Meyer F, Werncke CG. Synthesis, Properties, and Reactivity of a Linear NHC-Based Chromium(I) Silylamide. Organometallics 2023. [DOI: 10.1021/acs.organomet.3c00013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/31/2023]
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8
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Sieg G, Müller I, Weißer K, Werncke CG. Taming the stilbene radical anion. Chem Sci 2022; 13:13872-13878. [PMID: 36544743 PMCID: PMC9710230 DOI: 10.1039/d2sc04451j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2022] [Accepted: 11/08/2022] [Indexed: 11/11/2022] Open
Abstract
Radical anions appear as intermediates in a variety of organic reductions and have recently garnered interest for their role as mediators for electron-driven catalysis as well as for organic electron conductor materials. Due to their unstable nature, the isolation of such organic radical anions is usually only possible by using extended aromatic systems, whereas non-aromatic unsaturated hydrocarbons have so far only been observed in situ. We herein report the first isolation, structure and spectroscopic characterization of a simple aryl substituted alkene radical anion, namely that of stilbene (1,2-diphenyl ethylene), achieved by encapsulation between two [K{18c6}] cations. The formation of the radical anion is accompanied by Z → E isomerization of the involved double bond, also on a catalytic scale. Employing the linear iron(i) complex [Fe(NR2)2]- as a reductant and coordination site also allows for this transformation, via formation of an iron(ii) bound radical anion. The use of the iron complex now also allows for Z → E isomerization of electron richer, simple alkenes bearing either mixed alkyl/aryl or even bis(alkyl) substitution.
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Affiliation(s)
- Grégoire Sieg
- Fachbereich Chemie, Philipps-Universität MarburgHans-Meerwein-Straße 435037 MarburgGermany
| | - Igor Müller
- Fachbereich Chemie, Philipps-Universität MarburgHans-Meerwein-Straße 435037 MarburgGermany
| | - Kilian Weißer
- Institut für Chemie, Humboldt-Universität zu BerlinBrook-Taylor-Str. 212489 BerlinGermany
| | - C. Gunnar Werncke
- Fachbereich Chemie, Philipps-Universität MarburgHans-Meerwein-Straße 435037 MarburgGermany
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9
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Reckziegel A, Battistella B, Schmidt A, Werncke CG. Intricate Road to Linear Anionic Nickel(I) Hexamethyldisilazanide [Ni(N(SiMe 3) 2) 2] . Inorg Chem 2022; 61:7794-7803. [PMID: 35522526 DOI: 10.1021/acs.inorgchem.2c00214] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
In this report, we present intricate pathways for the synthesis of linear nickel(I) silylamide K{m}[Ni(NR2)2] (NR2 = -N(SiMe3)2). This is achieved first via the reduction of nickel(II) trisamide Li(donor)4[Ni(NR2)3] (Li(thf)x[1]) with KC8 in the presence of 18-crown-6 or crypt.222. In due course, the behavior of Li(donor)4[Ni(NR2)3] as a source of masked two-coordinate nickel(II) hexamethyldisilazanide is explored, leading to the formation of nickel(I) and nickel(II) N-donor adducts, as well as metal-metal-bonded dinickel(I) trisamide K(toluene)[Ni2(NR2)3] (K(toluene)[5]). Finally, a convenient and reliable synthesis of K{m}[Ni(NR2)2] by ligand exchange of phosphines in [Ni(NR2)(PPh3)2] with K{m}(NR2) is presented. This allows for the comprehensive analysis of its electronic properties which reveals a fluxional behavior in solution with tight anion/cation interactions.
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Affiliation(s)
- Alexander Reckziegel
- Department of Chemistry, Philipps University Marburg, Hans-Meerwein Straße 4, D-35037 Marburg, Germany
| | - Beatrice Battistella
- Institute of Chemistry, Humboldt-University Berlin, Brook-Taylor-Str. 2, D-12489 Berlin, Germany
| | - Andreas Schmidt
- Department of Chemistry, Philipps University Marburg, Hans-Meerwein Straße 4, D-35037 Marburg, Germany
| | - C Gunnar Werncke
- Department of Chemistry, Philipps University Marburg, Hans-Meerwein Straße 4, D-35037 Marburg, Germany
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10
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Zars E, Gravogl L, Gau M, Carroll PJ, Meyer K, Mindiola DJ. Iron(II) Mediated Deazotation of Benzyl Azide: Trapping and Subsequent Transformations of the Benzaldimine Fragment. Inorg Chem 2022; 61:1079-1090. [PMID: 34978453 DOI: 10.1021/acs.inorgchem.1c03243] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The mono-benzaldimine (HN═CHPh) complex [(tBupyrpyrr2)Fe(HN═CHPh)] (1-HN═CHPh) has been prepared by reaction of [(tBupyrpyrr2)Fe(OEt2)] (1-OEt2) (tBupyrpyrr2 = 2,6-bis(3,5-di-tert-butyl-pyrrolyl)pyridine) with one equivalent of benzyl azide. Compound 1-HN═CHPh retains the cis-divacant octahedral coordination geometry akin to 1, as established by single crystal X-ray diffraction study. A bis-HN═CHPh complex [(tBupyrpyrr2)Fe(HN═CHPh)2] (2) was also prepared by the addition of two equivalents of benzyl azide to 1, and its molecular structure exhibits the two HN═CHPh ligands coordinated trans to each other, thereby forming a square pyramidal coordination geometry at the FeII center. Reaction of 1 with excess benzyl azide yields [(tBupyrpyrr2)Fe(HN═CHPh)2·PhCHNCH(NH2)Ph] (2-PhCHNCH(NH2)Ph), which contains an unstable benzylideneamino phenyl methanamine fragment, effectively hydrogen bonded to 2. Thermolysis of 2 or 2-PhCHNCH(NH2)Ph releases the HN═CHPh self-coupling products hydrobenzamide (A), N-benzylidine benzylamine (B), and benzonitrile (C). Under catalytic conditions, free HN═CHPh (cis/trans-HN═CHPh mixture) is produced using 2.5 mol % of 1 in 90% spectroscopic yield. These studies provide a clearer understanding for the conversion of the HN═CHPh in 2 or 2-PhCHNCH(NH2)Ph to the C-C and C-N coupled products. Reduction of 1-HN═CHPh with KC8 yields the reductively coupled benzylamide complex [K(OEt2)]2[(tBupyrpyrr2)2Fe2(μ2-NHCHPhCHPhNH)] (3) as the result of a new C-C bond formed between two radical benzylamide fragments.
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Affiliation(s)
- Ethan Zars
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
| | - Lisa Gravogl
- Friedrich-Alexander-University Erlangen-Nürnberg (FAU), Department of Chemistry and Pharmacy, Inorganic Chemistry, Egerlandstr. 1, Erlangen 91058, Germany
| | - Michael Gau
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
| | - Patrick J Carroll
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
| | - Karsten Meyer
- Friedrich-Alexander-University Erlangen-Nürnberg (FAU), Department of Chemistry and Pharmacy, Inorganic Chemistry, Egerlandstr. 1, Erlangen 91058, Germany
| | - Daniel J Mindiola
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
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