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Knüpfer C, Klerner L, Raucheisen M, Langer J, Harder S. Synthesis of Superbulky Amide Ligands by Addition of Polar Reagents to Sila-Imine. Chemistry 2024; 30:e202400715. [PMID: 38501797 DOI: 10.1002/chem.202400715] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2024] [Revised: 03/19/2024] [Accepted: 03/19/2024] [Indexed: 03/20/2024]
Abstract
The chemistry of extremely bulky amide ligands is troubled by difficulties in deprotonation of the parent amine. As an alternative route to superbulky amide reagents, the addition of polar reagents to a sila-imine has been investigated. Attempts to synthesize the superbulky amide anion (tBu3Si)2N- by addition of tBuLi to tBu2Si=N(SitBu3) failed and gave tBu3Si(tBu2HSi)NLi and isobutene. Reaction of the sila-imine with KOtBu successfully led to tBu3Si[tBu2(tBuO)Si]NK which crystallized as a separated ion-pair. Reaction with the slightly bulkier KOAd (Ad=1-adamantyl) led in presence of THF to ether ring-opening. Reaction with tBuOH gave tBu3Si[tBu2(tBuO)Si]NH but this amine cannot be easily deprotonated. Reaction with (BDI*)MgnBu in presence of THF gave (BDI*)Mg+ ⋅ (THF)2 and the non-coordinating anion tBu3Si[tBu2(nBu)Si]N-; BDI*=ß-diketiminate ligand HC[C(tBu)N-DIPP]2, DIPP=2,6-diisopropylphenyl. Reaction of Mg(nBu)2 with tBu2Si=N(SitBu3) led to a Mg complex with one amide ligand: tBu3Si[tBu2(nBu)Si]N-. The other superbulky amide anion isomerized by internal deprotonation of a tBu-substituent to give a primary carbanion that is also coordinated to Mg. Although the amide-to-carbanion isomerization is highly contrathermodynamic, it allows for coordination of both anions to a single Mg center. The new bulky amides are rare cases of halogen-free weakly coordinating anions.
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Affiliation(s)
- Christian Knüpfer
- Inorganic and Organometallic Chemistry, Friedrich-Alexander-Universität Erlangen-Nürnberg, Egerlandstraße 1, 91058, Erlangen, Germany
| | - Lukas Klerner
- Inorganic and Organometallic Chemistry, Friedrich-Alexander-Universität Erlangen-Nürnberg, Egerlandstraße 1, 91058, Erlangen, Germany
| | - Michael Raucheisen
- Inorganic and Organometallic Chemistry, Friedrich-Alexander-Universität Erlangen-Nürnberg, Egerlandstraße 1, 91058, Erlangen, Germany
| | - Jens Langer
- Inorganic and Organometallic Chemistry, Friedrich-Alexander-Universität Erlangen-Nürnberg, Egerlandstraße 1, 91058, Erlangen, Germany
| | - Sjoerd Harder
- Inorganic and Organometallic Chemistry, Friedrich-Alexander-Universität Erlangen-Nürnberg, Egerlandstraße 1, 91058, Erlangen, Germany
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2
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Nguyen DT, Helling C, Evans MJ, Jones C. Enforcing Metal-Arene Interactions in Bulky p-Terphenyl Bis(anilide) Complexes of Group 2 Metals (Be-Ba): Potential Precursors for Low-Oxidation-State Alkaline Earth Metal Systems. Inorg Chem 2024; 63:5718-5726. [PMID: 38471088 DOI: 10.1021/acs.inorgchem.4c00207] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/14/2024]
Abstract
An extremely bulky p-terphenyl bis(aniline), p-C6H4{C6H4[N(H)TCHP]-2}2 (TCHP = 2,4,6-tricyclohexylphenyl) TCHPTerphH2, has been developed. Deprotonation of a less bulky analogue, DipTerphH2 (Dip = 2,6-diisopropylphenyl), with BePh2 affords the bimetallic system, [(BePh)2(μ-DipTerph)] 1. Treating either TCHPTerphH2 or DipTerphH2 with Mg{CH2(SiMe3)}2 gives the monomeric bis(anilide) complexes [Mg(ArTerph)] (Ar = Dip 2, TCHP 3) which display rare examples of η6-arene coordination to the metal center. Treating 2 with THF leads to partial dissociation of the Mg···arene interaction and formation of [Mg(DipTerph)(THF)] 4. Reactions of the bis(aniline)s with the group 2 metal amides [M{N(SiMe3)2}2] afford dimeric, structurally analogous compounds [{M(ArTerph)}2] (Ar = Dip, M = Ca 5, Sr 6, Ba 7; Ar = TCHP, M = Ca 8, Sr 9, Ba 10) which display intermolecular M···arene interactions in the solid state. Computational studies have shown that the intramolecular M···η6-arene interactions in models of the ether-free metal bis(anilide) compounds are largely electrostatic in nature. Reductions of these compounds with alkali metals led to mixtures of unidentified products.
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Affiliation(s)
- Dat T Nguyen
- School of Chemistry, Monash University, P.O. Box 23, Melbourne 3800, Victoria, Australia
| | - Christoph Helling
- School of Chemistry, Monash University, P.O. Box 23, Melbourne 3800, Victoria, Australia
| | - Matthew J Evans
- School of Chemistry, Monash University, P.O. Box 23, Melbourne 3800, Victoria, Australia
| | - Cameron Jones
- School of Chemistry, Monash University, P.O. Box 23, Melbourne 3800, Victoria, Australia
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3
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Lyubov DM, Zakaria H, Nelyubina YV, Aysin RR, Bukalov SS, Trifonov AA. Ca(II) and Yb(II) complexes featuring M(C≡C) 4 structural motif: enforced proximity or genuine η 2 -bonding? Chemistry 2024; 30:e202303533. [PMID: 38070175 DOI: 10.1002/chem.202303533] [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: 10/25/2023] [Indexed: 01/12/2024]
Abstract
Bis(carbazolide) complexes M[3,6-tBu2 -1,8-(RC≡C)2 Carb]2 (THF)n (R=SiMe3 , n=0, M=Ca, Yb; R=Ph, n=1, M=Ca, Yb; n=0, M=Yb) were synthesized through transamination reaction of M[N(SiMe3 )2 ]2 (THF)2 with two molar equivalents of carbazoles. The complexes feature M(η2 -C≡C)4 structural motif composed of M(II) ions encapsulated by four acetylene fragments due to atypical for alkaline- and rare-earth metals η2 -interactions with triple C≡C bond. This interaction is evidenced experimentally by X-ray diffraction, Raman spectroscopy in the solid state and by NMR-spectroscopy in the solution. According to QTAIM analysis there are 4 bond critical points (3;-1) between the metal atom and each of the triple bonds, which are connected by a strongly curved, almost T-shaped bond pathway.
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Affiliation(s)
- Dmitry M Lyubov
- G. A. Razuvaev Institute of Organometallic Chemistry of Russian Academy of Sciences, Russia, 49 Tropinina str., GSP-445, 603950, Nizhny Novgorod
| | - Hamza Zakaria
- G. A. Razuvaev Institute of Organometallic Chemistry of Russian Academy of Sciences, Russia, 49 Tropinina str., GSP-445, 603950, Nizhny Novgorod
- N. I. Lobachevsky State University of Nizhny Novgorod, Gagarina Avenue 23, 603950, Nizhny Novgorod, Russia
| | - Yulia V Nelyubina
- A. N. Nesmeyanov Institute of Organoelement Compounds of Russian Academy of Sciences, Gagarina Avenue 23, 603950, Nizhny Novgorod, Russia
- 28 Vavilova str., 119334, Moscow, Russia
| | - Rinat R Aysin
- A. N. Nesmeyanov Institute of Organoelement Compounds of Russian Academy of Sciences, Gagarina Avenue 23, 603950, Nizhny Novgorod, Russia
- 28 Vavilova str., 119334, Moscow, Russia
| | - Sergey S Bukalov
- A. N. Nesmeyanov Institute of Organoelement Compounds of Russian Academy of Sciences, Gagarina Avenue 23, 603950, Nizhny Novgorod, Russia
- 28 Vavilova str., 119334, Moscow, Russia
| | - Alexander A Trifonov
- G. A. Razuvaev Institute of Organometallic Chemistry of Russian Academy of Sciences, Russia, 49 Tropinina str., GSP-445, 603950, Nizhny Novgorod
- A. N. Nesmeyanov Institute of Organoelement Compounds of Russian Academy of Sciences, Gagarina Avenue 23, 603950, Nizhny Novgorod, Russia
- 28 Vavilova str., 119334, Moscow, Russia
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4
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Chen MT, Wu PZ, Liao CC, Hung KW, Shen PC. Grignard reagents as deprotonation agents for oxazoline-amido-phenolate ligands: structural and catalytic implications with the role of halogen ions. Dalton Trans 2024; 53:738-745. [PMID: 38086677 DOI: 10.1039/d3dt03733a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2024]
Abstract
In this study, various halogen-substituted Grignard reagents were assessed as deprotonating agents for the oxazoline-amido-phenolate ligand, leading to the formation of magnesium complexes. The newly synthesized complexes with halogen substituents displayed three distinct coordinative modes, all extensively characterized through crystallographic methods. The introduction of halogen substituents induced changes in the Lewis acid properties of the complexes, thereby impacting their structural attributes and catalytic behavior during the initiation and propagation of ring polymerization of cyclic esters.
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Affiliation(s)
- Ming-Tsz Chen
- Department of Applied Chemistry, Providence University, Taichung 43301, Taiwan, Republic of China.
| | - Pei-Zheng Wu
- Department of Applied Chemistry, Providence University, Taichung 43301, Taiwan, Republic of China.
| | - Chi-Chung Liao
- Department of Applied Chemistry, Providence University, Taichung 43301, Taiwan, Republic of China.
| | - Kai-Wei Hung
- Department of Applied Chemistry, Providence University, Taichung 43301, Taiwan, Republic of China.
| | - Pin-Chi Shen
- Department of Applied Chemistry, Providence University, Taichung 43301, Taiwan, Republic of China.
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5
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Harder S, Langer J. Opportunities with calcium Grignard reagents and other heavy alkaline-earth organometallics. Nat Rev Chem 2023; 7:843-853. [PMID: 37935796 DOI: 10.1038/s41570-023-00548-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/22/2023] [Indexed: 11/09/2023]
Abstract
More than a century old, magnesium Grignard reagents remain essential to the toolbox of organic chemists. Although similar reagents with the neighbouring group 2 metal Ca have been explored, the considerably higher polarity and reactivity of the Ca-C bond result in undesired decomposition pathways. Ca Grignard reagents have found academic interest but have never fully developed into an established synthetic tool. Recent research activities, however, provide facile access to these highly reactive organocalcium species, including in situ preparation and ball milling approaches to tackle the challenge of controlling their extreme sensitivity. Heavier Grignard reagents are not just more reactive but profit from unique chemical transformations. Insight into the transition metal-like properties of Ca, Sr and Ba is only just emerging. Considering the rapidly developing field of alkaline-earth metal-mediated catalysis, heavy Grignard reagents will probably have a bright future.
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Affiliation(s)
- Sjoerd Harder
- Inorganic Chemistry, Friedrich-Alexander Universität Erlangen-Nürnberg, Erlangen, Germany.
| | - Jens Langer
- Inorganic Chemistry, Friedrich-Alexander Universität Erlangen-Nürnberg, Erlangen, Germany
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6
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Echeverría J, Alvarez S. The borderless world of chemical bonding across the van der Waals crust and the valence region. Chem Sci 2023; 14:11647-11688. [PMID: 37920358 PMCID: PMC10619631 DOI: 10.1039/d3sc02238b] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2023] [Accepted: 07/01/2023] [Indexed: 11/04/2023] Open
Abstract
The definition of the van der Waals crust as the spherical section between the atomic radius and the van der Waals radius of an element is discussed and a survey of the application of the penetration index between two interacting atoms in a wide variety of covalent, polar, coordinative or noncovalent bonding situations is presented. It is shown that this newly defined parameter permits the comparison of bonding between pairs of atoms in structural and computational studies independently of the atom sizes.
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Affiliation(s)
- Jorge Echeverría
- Instituto de Síntesis Química y Catalisis Homogénea (ISQCH) and Departmento de Química Inorgánica, Facultad de Ciencias, Universidad de Zaragoza Pedro Cerbuna 12 50009 Zaragoza Spain
| | - Santiago Alvarez
- Department de Química Inorgànica i Orgànica, Secció de Química Inorgànica, e Institut de Química Teòrica i Computacional, Universitat de Barcelona Martí i Franquès 1-11 08028 -Barcelona Spain
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7
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Brouillet EV, Brown SA, Kennedy AR, Rae A, Walton HP, Robertson SD. Atom-economic access to cationic magnesium complexes. Dalton Trans 2023; 52:13332-13338. [PMID: 37671570 DOI: 10.1039/d3dt02669h] [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
Cationic alkaline-earth complexes attract interest for their enhanced Lewis acidity and reactivity compared with their neutral counterparts. Synthetic protocols to these complexes generally utilize expensive specialized reagents in reactions generating multiple by-products. We have studied a simple ligand transfer approach to these complexes using (NacNac)MgR and ER3 (NacNac = β-diketiminate anion; E = group 13 element; R = aryl/amido anion) which demonstrates high atom economy, opening up the ability to target these species in a more sustainable manner. The success of this methodology is dependent on the identity of the group 13 element with the heavier elements facilitating faster ligand exchange. Furthermore, while this reaction is successful with aromatic ligands such as phenyl and pyrrolyl, the secondary amide piperidide (pip) fails to transfer, which we attribute to the stronger 3-centre-4-electron dimerization interaction of Al2(pip)6.
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Affiliation(s)
- Etienne V Brouillet
- Department of Pure and Applied Chemistry, University of Strathclyde, 295 Cathedral Street, Glasgow, G1 1XL, UK.
| | - Scott A Brown
- Department of Pure and Applied Chemistry, University of Strathclyde, 295 Cathedral Street, Glasgow, G1 1XL, UK.
| | - Alan R Kennedy
- Department of Pure and Applied Chemistry, University of Strathclyde, 295 Cathedral Street, Glasgow, G1 1XL, UK.
| | - Annabel Rae
- Department of Pure and Applied Chemistry, University of Strathclyde, 295 Cathedral Street, Glasgow, G1 1XL, UK.
| | - Heather P Walton
- Department of Pure and Applied Chemistry, University of Strathclyde, 295 Cathedral Street, Glasgow, G1 1XL, UK.
| | - Stuart D Robertson
- Department of Pure and Applied Chemistry, University of Strathclyde, 295 Cathedral Street, Glasgow, G1 1XL, UK.
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8
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Mai J, Rösch B, Patel N, Langer J, Harder S. On the existence of low-valent magnesium-calcium complexes. Chem Sci 2023; 14:4724-4734. [PMID: 37181774 PMCID: PMC10171184 DOI: 10.1039/d3sc00909b] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2023] [Accepted: 04/13/2023] [Indexed: 05/16/2023] Open
Abstract
DFT-Calculations predict that a low-valent complex (BDI)Mg-Ca(BDI) with bulky β-diketiminate (BDI) ligands is thermodynamically stable. It was attempted to isolate such a complex by salt-metathesis between [(DIPePBDI*)Mg-Na+]2 and [(DIPePBDI)CaI]2 (DIPePBDI = HC[C(Me)N-DIPeP]2; DIPePBDI* = HC[C(tBu)N-DIPeP]2; DIPeP = 2,6-CH(Et)2-phenyl). Whereas in alkane solvents no reaction was observed, salt-metathesis in C6H6 led to immediate C-H activation of benzene to give (DIPePBDI*)MgPh and (DIPePBDI)CaH, the latter crystallizing as a THF-solvated dimer [(DIPePBDI)CaH·THF]2. Calculations suggest reduction and insertion of benzene in the Mg-Ca bond. The activation enthalpy for the subsequent decomposition of C6H62- into Ph- and H- is only 14.4 kcal mol-1. Repeating this reaction in the presence of naphthalene or anthracene led to heterobimetallic complexes in which naphthalene2- or anthracene2- anions are sandwiched between (DIPePBDI*)Mg+ and (DIPePBDI)Ca+ cations. These complexes slowly decompose to their homometallic counterparts and further decomposition products. Complexes in which naphthalene2- or anthracene2- anions are sandwiched between two (DIPePBDI)Ca+ cations were isolated. The low-valent complex (DIPePBDI*)Mg-Ca(DIPePBDI) could not be isolated due to its high reactivity. There is, however, strong evidence that this heterobimetallic compound is a fleeting intermediate.
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Affiliation(s)
- Jonathan Mai
- Inorganic and Organometallic Chemistry, Friedrich-Alexander-Universität Erlangen-Nürnberg Egerlandstraße 1 Erlangen 91058 Germany
| | - Bastian Rösch
- Inorganic and Organometallic Chemistry, Friedrich-Alexander-Universität Erlangen-Nürnberg Egerlandstraße 1 Erlangen 91058 Germany
| | - Neha Patel
- Inorganic and Organometallic Chemistry, Friedrich-Alexander-Universität Erlangen-Nürnberg Egerlandstraße 1 Erlangen 91058 Germany
| | - Jens Langer
- Inorganic and Organometallic Chemistry, Friedrich-Alexander-Universität Erlangen-Nürnberg Egerlandstraße 1 Erlangen 91058 Germany
| | - Sjoerd Harder
- Inorganic and Organometallic Chemistry, Friedrich-Alexander-Universität Erlangen-Nürnberg Egerlandstraße 1 Erlangen 91058 Germany
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9
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Buchner MR, Thomas-Hargreaves LR. s-Block chemistry in weakly coordinating solvents. Dalton Trans 2021; 50:16916-16922. [PMID: 34738606 DOI: 10.1039/d1dt03443j] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Alkaline earth metal catalysis has been a growing field in recent years. To enhance reactivity and to understand the metal-substrate interactions in more detail, reactions are increasingly carried out in weakly coordinating solvents. This article gives an overview over the two main approaches to facilitate this, which are either through the employment of highly dipolar haloaryls as solvents, or by increasing the solubility of the ligand systems. The resulting coordination modes and reactivities are presented together with the synthetic strategies. Additionally, the latest results of group 1 complex chemistry in aliphatic solvents are illustrated and future challenges are highlighted.
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Affiliation(s)
- Magnus R Buchner
- Anorganische Chemie, Nachwuchsgruppe Hauptgruppenmetallchemie, Fachbereich Chemie, Philipps-Universität Marburg, Hans-Meerwein-Straße 4, 35032 Marburg, Germany.
| | - Lewis R Thomas-Hargreaves
- Anorganische Chemie, Nachwuchsgruppe Hauptgruppenmetallchemie, Fachbereich Chemie, Philipps-Universität Marburg, Hans-Meerwein-Straße 4, 35032 Marburg, Germany.
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10
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Roy MMD, Omaña AA, Wilson ASS, Hill MS, Aldridge S, Rivard E. Molecular Main Group Metal Hydrides. Chem Rev 2021; 121:12784-12965. [PMID: 34450005 DOI: 10.1021/acs.chemrev.1c00278] [Citation(s) in RCA: 124] [Impact Index Per Article: 41.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
This review serves to document advances in the synthesis, versatile bonding, and reactivity of molecular main group metal hydrides within Groups 1, 2, and 12-16. Particular attention will be given to the emerging use of said hydrides in the rapidly expanding field of Main Group element-mediated catalysis. While this review is comprehensive in nature, focus will be given to research appearing in the open literature since 2001.
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Affiliation(s)
- Matthew M D Roy
- Inorganic Chemistry Laboratory, Department of Chemistry, University of Oxford, South Parks Road, Oxford OX1 3QR, United Kingdom
| | - Alvaro A Omaña
- Department of Chemistry, University of Alberta, 11227 Saskatchewan Drive, Edmonton, Alberta T6G 2G2, Canada
| | - Andrew S S Wilson
- Department of Chemistry, University of Bath, Avon BA2 7AY, United Kingdom
| | - Michael S Hill
- Department of Chemistry, University of Bath, Avon BA2 7AY, United Kingdom
| | - Simon Aldridge
- Inorganic Chemistry Laboratory, Department of Chemistry, University of Oxford, South Parks Road, Oxford OX1 3QR, United Kingdom
| | - Eric Rivard
- Department of Chemistry, University of Alberta, 11227 Saskatchewan Drive, Edmonton, Alberta T6G 2G2, Canada
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11
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Wiesinger M, Knüpfer C, Elsen H, Mai J, Langer J, Harder S. Heterometallic Mg−Ba Hydride Clusters in Hydrogenation Catalysis. ChemCatChem 2021. [DOI: 10.1002/cctc.202101071] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Affiliation(s)
- Michael Wiesinger
- Inorganic and Organometallic Chemistry Universität Erlangen-Nürnberg Egerlandstraße 1 91058 Erlangen Germany
| | - Christian Knüpfer
- Inorganic and Organometallic Chemistry Universität Erlangen-Nürnberg Egerlandstraße 1 91058 Erlangen Germany
| | - Holger Elsen
- Inorganic and Organometallic Chemistry Universität Erlangen-Nürnberg Egerlandstraße 1 91058 Erlangen Germany
| | - Jonathan Mai
- Inorganic and Organometallic Chemistry Universität Erlangen-Nürnberg Egerlandstraße 1 91058 Erlangen Germany
| | - Jens Langer
- Inorganic and Organometallic Chemistry Universität Erlangen-Nürnberg Egerlandstraße 1 91058 Erlangen Germany
| | - Sjoerd Harder
- Inorganic and Organometallic Chemistry Universität Erlangen-Nürnberg Egerlandstraße 1 91058 Erlangen Germany
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12
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Thum K, Pahl J, Eyselein J, Elsen H, Langer J, Harder S. Retro-Diels-Alder decomposition of norbornadiene mediated by a cationic magnesium complex. Chem Commun (Camb) 2021; 57:5278-5281. [PMID: 33942830 DOI: 10.1039/d1cc01691a] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
First evidence for the coordination of norbornadiene (nbd) and dicyclopentadiene (dcpd) with the main group metal Mg is provided by the crystal structures of adducts with cationic β-diketiminate (BDI) Mg complexes. While the dcpd complex is thermally stable, [(BDI)Mg+·nbd][B(C6F5)4-] shows slow room temperature retro-Diels-Alder decomposition to give a complex with the cation (BDI)Mg(C5H5)Mg(BDI)+.
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Affiliation(s)
- Katharina Thum
- Inorganic and Metallorganic Chemistry, Universität Erlangen-Nürnberg, Egerlandstrasse 1, Erlangen 91058, Germany.
| | - Jürgen Pahl
- Inorganic and Metallorganic Chemistry, Universität Erlangen-Nürnberg, Egerlandstrasse 1, Erlangen 91058, Germany.
| | - Jonathan Eyselein
- Inorganic and Metallorganic Chemistry, Universität Erlangen-Nürnberg, Egerlandstrasse 1, Erlangen 91058, Germany.
| | - Holger Elsen
- Inorganic and Metallorganic Chemistry, Universität Erlangen-Nürnberg, Egerlandstrasse 1, Erlangen 91058, Germany.
| | - Jens Langer
- Inorganic and Metallorganic Chemistry, Universität Erlangen-Nürnberg, Egerlandstrasse 1, Erlangen 91058, Germany.
| | - Sjoerd Harder
- Inorganic and Metallorganic Chemistry, Universität Erlangen-Nürnberg, Egerlandstrasse 1, Erlangen 91058, Germany.
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13
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Thum K, Martin J, Elsen H, Eyselein J, Stiegler L, Langer J, Harder S. Lewis Acidic Cationic Strontium and Barium Complexes. Eur J Inorg Chem 2021. [DOI: 10.1002/ejic.202100345] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Affiliation(s)
- Katharina Thum
- Chair of Inorganic and Organometallic Chemistry Universität Erlangen-Nürnberg Egerlandstraße 1 91058 Erlangen Germany
| | - Johannes Martin
- Chair of Inorganic and Organometallic Chemistry Universität Erlangen-Nürnberg Egerlandstraße 1 91058 Erlangen Germany
| | - Holger Elsen
- Chair of Inorganic and Organometallic Chemistry Universität Erlangen-Nürnberg Egerlandstraße 1 91058 Erlangen Germany
| | - Jonathan Eyselein
- Chair of Inorganic and Organometallic Chemistry Universität Erlangen-Nürnberg Egerlandstraße 1 91058 Erlangen Germany
| | - Lena Stiegler
- Chair of Inorganic and Organometallic Chemistry Universität Erlangen-Nürnberg Egerlandstraße 1 91058 Erlangen Germany
| | - Jens Langer
- Chair of Inorganic and Organometallic Chemistry Universität Erlangen-Nürnberg Egerlandstraße 1 91058 Erlangen Germany
| | - Sjoerd Harder
- Chair of Inorganic and Organometallic Chemistry Universität Erlangen-Nürnberg Egerlandstraße 1 91058 Erlangen Germany
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14
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Friedrich A, Eyselein J, Elsen H, Langer J, Pahl J, Wiesinger M, Harder S. Cationic Aluminium Complexes as Catalysts for Imine Hydrogenation. Chemistry 2021; 27:7756-7763. [PMID: 33780071 PMCID: PMC8252007 DOI: 10.1002/chem.202100641] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2021] [Indexed: 12/14/2022]
Abstract
Strongly Lewis acidic cationic aluminium complexes, stabilized by β–diketiminate (BDI) ligands and free of Lewis bases, have been prepared as their B(C6F5)4− salts and were investigated for catalytic activity in imine hydrogenation. The backbone (R1) and N (R2) substituents on the R1,R2BDI ligand (R1,R2BDI=HC[C(R1)N(R2)]2) influence sterics and Lewis acidity. Ligand bulk increases along the row Me,DIPPBDI<Me,DIPePBDI≈tBu,DIPPBDI<tBu,DIPePBDI; DIPP=2,6‐C(H)Me2‐phenyl, DIPeP=2,6‐C(H)Et2‐phenyl. The Gutmann‐Beckett test showed acceptor numbers of: (tBu,DIPPBDI)AlMe+ 85.6, (tBu,DIPePBDI)AlMe+ 85.9, (Me,DIPPBDI)AlMe+ 89.7, (Me,DIPePBDI)AlMe+ 90.8, (Me,DIPPBDI)AlH+ 95.3. Steric and electronic factors need to be balanced for catalytic activity in imine hydrogenation. Open, highly Lewis acidic, cations strongly coordinate imine rendering it inactive as a Frustrated Lewis Pair (FLP). The bulkiest cations do not coordinate imine but its combination is also not an active catalyst. The cation (tBu,DIPPBDI)AlMe+ shows the best catalytic activity for various imines and is also an active catalyst for the Tishchenko reaction of benzaldehyde to benzylbenzoate. DFT calculations on the mechanism of imine hydrogenation catalysed by cationic Al complexes reveal two interconnected catalytic cycles operating in concert. Hydrogen is activated either by FLP reactivity of an Al⋅⋅⋅imine couple or, after formation of significant quantities of amine, by reaction with an Al⋅⋅⋅amine couple. The latter autocatalytic Al⋅⋅⋅amine cycle is energetically favoured.
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Affiliation(s)
- Alexander Friedrich
- Inorganic and Organometallic Chemistry, Friedrich-Alexander-Universität Erlangen-Nürnberg, Egerlandstraße 1, 91058, Erlangen, Germany
| | - Jonathan Eyselein
- Inorganic and Organometallic Chemistry, Friedrich-Alexander-Universität Erlangen-Nürnberg, Egerlandstraße 1, 91058, Erlangen, Germany
| | - Holger Elsen
- Inorganic and Organometallic Chemistry, Friedrich-Alexander-Universität Erlangen-Nürnberg, Egerlandstraße 1, 91058, Erlangen, Germany
| | - Jens Langer
- Inorganic and Organometallic Chemistry, Friedrich-Alexander-Universität Erlangen-Nürnberg, Egerlandstraße 1, 91058, Erlangen, Germany
| | - Jürgen Pahl
- Inorganic and Organometallic Chemistry, Friedrich-Alexander-Universität Erlangen-Nürnberg, Egerlandstraße 1, 91058, Erlangen, Germany
| | - Michael Wiesinger
- Inorganic and Organometallic Chemistry, Friedrich-Alexander-Universität Erlangen-Nürnberg, Egerlandstraße 1, 91058, Erlangen, Germany
| | - Sjoerd Harder
- Inorganic and Organometallic Chemistry, Friedrich-Alexander-Universität Erlangen-Nürnberg, Egerlandstraße 1, 91058, Erlangen, Germany
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15
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Koptseva TS, Sokolov VG, Ketkov SY, Rychagova EA, Cherkasov AV, Skatova AA, Fedushkin IL. Reversible Addition of Carbon Dioxide to Main Group Metal Complexes at Temperatures about 0 °C. Chemistry 2021; 27:5745-5753. [PMID: 33645870 DOI: 10.1002/chem.202004991] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2020] [Revised: 01/19/2021] [Indexed: 11/08/2022]
Abstract
The reaction of dialane [LAl-AlL] (1; L=dianion of 1,2-bis[(2,6-diisopropylphenyl)imino]acenaphthene, dpp-bian) with carbon dioxide results in two different products depending on solvent. In toluene at temperatures of about 0 °C, the reaction gives cycloadduct [L(CO2 )Al-Al(O2 C)L] (2), whereas in diethyl ether, the reaction affords oxo-bridged carbamato derivative [L(CO2 )(Et2 O)Al(μ-O)AlL] (3). The DFT and QTAIM calculations provide reasonable explanations for the reversible formation of complex 2 in the course of two subsequent (2+4) cycloaddition reactions. Consecutive transition states with low activation barriers were revealed. Also, the DFT study demonstrated a crucial effect of diethyl ether coordination to aluminium on the reaction of dialane 1 with CO2 . The optimized structures of key intermediates were obtained for the reactions in the presence of Et2 O; calculated thermodynamic parameters unambiguously testify the irreversible formation of the product 3.
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Affiliation(s)
- Tatyana S Koptseva
- G.A. Razuvaev Institute of Organometallic Chemistry of, Russian Academy of Sciences, 603950, Nizhny Novgorod, Tropinina str. 49, Russian Federation
| | - Vladimir G Sokolov
- G.A. Razuvaev Institute of Organometallic Chemistry of, Russian Academy of Sciences, 603950, Nizhny Novgorod, Tropinina str. 49, Russian Federation
| | - Sergey Yu Ketkov
- G.A. Razuvaev Institute of Organometallic Chemistry of, Russian Academy of Sciences, 603950, Nizhny Novgorod, Tropinina str. 49, Russian Federation
| | - Elena A Rychagova
- G.A. Razuvaev Institute of Organometallic Chemistry of, Russian Academy of Sciences, 603950, Nizhny Novgorod, Tropinina str. 49, Russian Federation
| | - Anton V Cherkasov
- G.A. Razuvaev Institute of Organometallic Chemistry of, Russian Academy of Sciences, 603950, Nizhny Novgorod, Tropinina str. 49, Russian Federation
| | - Alexandra A Skatova
- G.A. Razuvaev Institute of Organometallic Chemistry of, Russian Academy of Sciences, 603950, Nizhny Novgorod, Tropinina str. 49, Russian Federation
| | - Igor L Fedushkin
- G.A. Razuvaev Institute of Organometallic Chemistry of, Russian Academy of Sciences, 603950, Nizhny Novgorod, Tropinina str. 49, Russian Federation
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Ramler J, Wüst L, Rempel A, Wolz L, Lichtenberg C. Bismuth Atoms in Hydrocarbon Ligands: Bismepines as Rigid, Ditopic Arene Donors in Coordination Chemistry. Organometallics 2021. [DOI: 10.1021/acs.organomet.1c00020] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Jacqueline Ramler
- Julius-Maximilians-University Würzburg, Institute of Inorganic Chemistry, Am Hubland 97074, Würzburg, Germany
| | - Leonie Wüst
- Julius-Maximilians-University Würzburg, Institute of Inorganic Chemistry, Am Hubland 97074, Würzburg, Germany
| | - Anna Rempel
- Julius-Maximilians-University Würzburg, Institute of Inorganic Chemistry, Am Hubland 97074, Würzburg, Germany
| | - Laura Wolz
- Julius-Maximilians-University Würzburg, Institute of Inorganic Chemistry, Am Hubland 97074, Würzburg, Germany
| | - Crispin Lichtenberg
- Julius-Maximilians-University Würzburg, Institute of Inorganic Chemistry, Am Hubland 97074, Würzburg, Germany
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17
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Thum K, Friedrich A, Pahl J, Elsen H, Langer J, Harder S. Unsupported Mg-Alkene Bonding. Chemistry 2021; 27:2513-2522. [PMID: 33197075 PMCID: PMC7898539 DOI: 10.1002/chem.202004716] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2020] [Indexed: 01/23/2023]
Abstract
The first intermolecular early main group metal-alkene complexes were isolated. This was enabled by using highly Lewis acidic Mg centers in the Lewis base-free cations (Me BDI)Mg+ and (tBu BDI)Mg+ with B(C6 F5 )4 - counterions (Me BDI=CH[C(CH3 )N(DIPP)]2 , tBu BDI=CH[C(tBu)N(DIPP)]2 , DIPP=2,6-diisopropylphenyl). Coordination complexes with various mono- and bis-alkene ligands, typically used in transition metal chemistry, were structurally characterized for 1,3-divinyltetramethyldisiloxane, 1,5-cyclooctadiene, cyclooctene, 1,3,5-cycloheptatriene, 2,3-dimethylbuta-1,3-diene, and 2-ethyl-1-butene. In all cases, asymmetric Mg-alkene bonding with a short and a long Mg-C bond is observed. This asymmetry is most extreme for Mg-(H2 C=CEt2 ) bonding. In bromobenzene solution, the Mg-alkene complexes are either dissociated or in a dissociation equilibrium. A DFT study and AIM analysis showed that the C=C bonds hardly change on coordination and there is very little alkene→Mg electron transfer. The Mg-alkene bonds are mainly electrostatic and should be described as Mg2+ ion-induced dipole interactions.
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Affiliation(s)
- Katharina Thum
- Chair of Inorganic and Organometallic ChemistryUniversität Erlangen-NürnbergEgerlandstrasse 191058ErlangenGermany
| | - Alexander Friedrich
- Chair of Inorganic and Organometallic ChemistryUniversität Erlangen-NürnbergEgerlandstrasse 191058ErlangenGermany
| | - Jürgen Pahl
- Chair of Inorganic and Organometallic ChemistryUniversität Erlangen-NürnbergEgerlandstrasse 191058ErlangenGermany
| | - Holger Elsen
- Chair of Inorganic and Organometallic ChemistryUniversität Erlangen-NürnbergEgerlandstrasse 191058ErlangenGermany
| | - Jens Langer
- Chair of Inorganic and Organometallic ChemistryUniversität Erlangen-NürnbergEgerlandstrasse 191058ErlangenGermany
| | - Sjoerd Harder
- Chair of Inorganic and Organometallic ChemistryUniversität Erlangen-NürnbergEgerlandstrasse 191058ErlangenGermany
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Friedrich A, Eyselein J, Langer J, Harder S. Comparison of Magnesium and Zinc in Cationic π-Arene and Halobenzene Complexes. Organometallics 2021. [DOI: 10.1021/acs.organomet.0c00786] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Alexander Friedrich
- Inorganic and Organometallic Chemistry, Friedrich-Alexander-Universität Erlangen-Nürnberg, Egerlandstraße 1, 91058 Erlangen, Germany
| | - Jonathan Eyselein
- Inorganic and Organometallic Chemistry, Friedrich-Alexander-Universität Erlangen-Nürnberg, Egerlandstraße 1, 91058 Erlangen, Germany
| | - Jens Langer
- Inorganic and Organometallic Chemistry, Friedrich-Alexander-Universität Erlangen-Nürnberg, Egerlandstraße 1, 91058 Erlangen, Germany
| | - Sjoerd Harder
- Inorganic and Organometallic Chemistry, Friedrich-Alexander-Universität Erlangen-Nürnberg, Egerlandstraße 1, 91058 Erlangen, Germany
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McMullen JS, Edwards AJ, Hicks J. C-H and C-F coordination of arenes in neutral alkaline earth metal complexes. Dalton Trans 2021; 50:8685-8689. [PMID: 34160514 DOI: 10.1039/d1dt01532j] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
A series of neutral magnesium and calcium complexes bearing an extremely bulky diamido ligand have been synthesised and crystallographically characterised. A number of these complexes feature rare group 2 metalaromatic interactions, such as the η6-coordination of benzene and 'agostic-like' C-H coordination, the latter previously unseen in neutral Mg and Ca complexes.
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Affiliation(s)
- Jacob S McMullen
- Research School of Chemistry, Australian National University, ACT 2601, Australia.
| | - Alison J Edwards
- Australian Centre for Neutron Scattering, Australian Nuclear Science and Technology Organisation, Sydney, New South Wales 2234, Australia
| | - Jamie Hicks
- Research School of Chemistry, Australian National University, ACT 2601, Australia.
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20
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Friedrich A, Pahl J, Eyselein J, Langer J, van Eikema Hommes N, Görling A, Harder S. Magnesium-halobenzene bonding: mapping the halogen sigma-hole with a Lewis-acidic complex. Chem Sci 2020; 12:2410-2418. [PMID: 34164006 PMCID: PMC8179342 DOI: 10.1039/d0sc06321e] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Complexes of the Lewis base-free cations (MeBDI)Mg+ and ( tBuBDI)Mg+ with Ph-X ligands (X = F, Cl, Br, I) have been studied (MeBDI = HC[C(Me)N-DIPP]2 and tBuBDI = HC[C(tBu)N-DIPP]2; DIPP = 2,6-diisopropylphenyl). For the smaller β-diketiminate ligand (MeBDI) only complexes with PhF could be isolated. Heavier Ph-X ligands could not compete with bonding of Mg to the weakly coordinating anion B(C6F5)4 -. For the cations with the bulkier tBuBDI ligand, the full series of halobenzene complexes was structurally characterized. Crystal structures show that the Mg⋯X-Ph angle strongly decreases with the size of X: F 139.1°, Cl 101.4°, Br 97.7°, I 95.1°. This trend, which is supported by DFT calculations, can be explained with the σ-hole which increases from F to I. Charge calculation and Atoms-In-Molecules analyses show that Mg⋯F-Ph bonding originates from electrostatic attraction between Mg2+ and the very polar C δ+-F δ- bond. For the heavier halobenzenes, polarization of the halogen atom becomes increasingly important (Cl < Br < I). Complexation with Mg leads in all cases to significant Ph-X bond activation and elongation. This unusual coordination of halogenated species to early main group metals is therefore relevant to C-X bond breaking.
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Affiliation(s)
- Alexander Friedrich
- Inorganic and Organometallic Chemistry, Friedrich-Alexander-Universität Erlangen-Nürnberg Egerlandstraße 1 91058 Erlangen Germany
| | - Jürgen Pahl
- Inorganic and Organometallic Chemistry, Friedrich-Alexander-Universität Erlangen-Nürnberg Egerlandstraße 1 91058 Erlangen Germany
| | - Jonathan Eyselein
- Inorganic and Organometallic Chemistry, Friedrich-Alexander-Universität Erlangen-Nürnberg Egerlandstraße 1 91058 Erlangen Germany
| | - Jens Langer
- Inorganic and Organometallic Chemistry, Friedrich-Alexander-Universität Erlangen-Nürnberg Egerlandstraße 1 91058 Erlangen Germany
| | - Nico van Eikema Hommes
- Computer Chemistry Center, Friedrich-Alexander-Universität Erlangen-Nürnberg Nägelsbachstraße 25 91052 Erlangen Germany.,Theoretical Chemistry, Friedrich-Alexander-Universität Erlangen-Nürnberg Egerlandstraße 3 91058 Erlangen Germany
| | - Andreas Görling
- Theoretical Chemistry, Friedrich-Alexander-Universität Erlangen-Nürnberg Egerlandstraße 3 91058 Erlangen Germany
| | - Sjoerd Harder
- Inorganic and Organometallic Chemistry, Friedrich-Alexander-Universität Erlangen-Nürnberg Egerlandstraße 1 91058 Erlangen Germany
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21
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Schorpp M, Krossing I. Stack by Stack: From the Free Cyclopentadienylgermanium Cation Via Heterobimetallic Main-Group Sandwiches to Main-Group Sandwich Coordination Polymers. Chemistry 2020; 26:14109-14117. [PMID: 32745294 PMCID: PMC7702131 DOI: 10.1002/chem.202002932] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2020] [Revised: 07/27/2020] [Indexed: 01/17/2023]
Abstract
Heterobimetallic cationic sandwich complexes [M(μ-Cp)M'Cp]+ of group 13 (M=Ga, In) and group 14 (M'=Ge, Sn) elements have been prepared as [WCA]- salts (WCA=Al(ORF )4 ; ORF =OC(CF3 )3 ). Their molecular structures include free apical gallium or indium atoms. The sandwich complexes were formed in the reactions of [M(HMB)]+ [WCA]- (HMB=C6 Me6 ) with the free metallocenes [M'Cp2 ]. Their structures are related to known stannocene and stannocenium salts; the unprecedented germanium analogues, namely the free germanocenium cation [GeCp]+ and the corresponding triple-decker complex cation [CpGe(μ-Cp)GeCp]+ , are described herein. By variation of the reaction conditions, these sandwich complexes can be transformed into the group 13/14 mixed cationic coordination polymer [{In(HMB)(μ-SnCp2 )}n ][WCA]n . This polymeric chain motif was also successfully replicated by the synthesis of complexes [{Ga/In(HMB)(μ-FeCp2 )}n ][WCA]n containing FeCp2 as a bridging ligand.
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Affiliation(s)
- Marcel Schorpp
- Institut für Anorganische und Analytische Chemie and Freiburger Materialforschungszentrum (FMF)Albert-Ludwigs-Universität FreiburgAlbertstr. 2179104FreiburgGermany
| | - Ingo Krossing
- Institut für Anorganische und Analytische Chemie and Freiburger Materialforschungszentrum (FMF)Albert-Ludwigs-Universität FreiburgAlbertstr. 2179104FreiburgGermany
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22
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Casey KC, Appiah JK, Robinson JR. Low-Symmetry β-Diketimine Aryloxide Rare-Earth Complexes: Flexible, Reactive, and Selective. Inorg Chem 2020; 59:14827-14837. [PMID: 32986427 DOI: 10.1021/acs.inorgchem.0c02170] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
We report the synthesis, characterization, and reactivity of a new low-symmetry β-diketimine featuring a pendant amino(methyl)phenol donor and its corresponding heteroleptic rare-earth (RE) complexes. This includes the first structurally characterized examples of alcoholysis and insertion from an isolated REIII amide in a β-diketimine framework. The flexible methylene linkage leads to REIII complexes with tunable dynamic solution behavior that defines their stoichiometric and catalytic reactivity. The addition of a strong neutral donor ligand, tricyclohexylphosphine oxide, suppresses a prevalent catalyst degradation pathway (base-promoted elimination) and dramatically enhances the catalyst performance in the stereospecific ring-opening polymerization of rac-β-butyrolactone. Our results further demonstrate the importance of ligand reorganization in the stoichiometric and catalytic activity of REIII ions.
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Affiliation(s)
- Kerry C Casey
- Department of Chemistry, Brown University, 324 Brook Street, Providence, Rhode Island 02912, United States
| | - Jude K Appiah
- Department of Chemistry, Brown University, 324 Brook Street, Providence, Rhode Island 02912, United States
| | - Jerome R Robinson
- Department of Chemistry, Brown University, 324 Brook Street, Providence, Rhode Island 02912, United States
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Dabringhaus P, Schorpp M, Scherer H, Krossing I. A Highly Lewis Acidic Strontium ansa-Arene Complex for Lewis Acid Catalysis and Isobutylene Polymerization. Angew Chem Int Ed Engl 2020; 59:22023-22027. [PMID: 32776669 PMCID: PMC7756322 DOI: 10.1002/anie.202010019] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2020] [Indexed: 12/18/2022]
Abstract
The potential of a dicationic strontium ansa‐arene complex for Lewis acid catalysis has been explored. The key to its synthesis was a simple salt metathesis from SrI2 and 2 Ag[Al(ORF)4], giving the base‐free strontium‐perfluoroalkoxyaluminate Sr[Al(ORF)4]2 (ORF=OC(CF3)3). Addition of an ansa‐arene yielded the highly Lewis acidic, dicationic strontium ansa‐arene complex. In preliminary experiments, the complex was successfully applied as a catalyst in CO2‐reduction to CH4 and a surprisingly controlled isobutylene polymerization reaction.
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Affiliation(s)
- Philipp Dabringhaus
- Institut für anorganische und analytische Chemie, Albert-Ludwigs-Universität Freiburg, Albertstraße 21, 79104, Freiburg i.Br., Germany
| | - Marcel Schorpp
- Institut für anorganische und analytische Chemie, Albert-Ludwigs-Universität Freiburg, Albertstraße 21, 79104, Freiburg i.Br., Germany
| | - Harald Scherer
- Institut für anorganische und analytische Chemie, Albert-Ludwigs-Universität Freiburg, Albertstraße 21, 79104, Freiburg i.Br., Germany
| | - Ingo Krossing
- Institut für anorganische und analytische Chemie, Albert-Ludwigs-Universität Freiburg, Albertstraße 21, 79104, Freiburg i.Br., Germany
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Dabringhaus P, Schorpp M, Scherer H, Krossing I. A Highly Lewis Acidic Strontium
ansa
‐Arene Complex for Lewis Acid Catalysis and Isobutylene Polymerization. Angew Chem Int Ed Engl 2020. [DOI: 10.1002/ange.202010019] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Affiliation(s)
- Philipp Dabringhaus
- Institut für anorganische und analytische Chemie Albert-Ludwigs-Universität Freiburg Albertstraße 21 79104 Freiburg i.Br. Germany
| | - Marcel Schorpp
- Institut für anorganische und analytische Chemie Albert-Ludwigs-Universität Freiburg Albertstraße 21 79104 Freiburg i.Br. Germany
| | - Harald Scherer
- Institut für anorganische und analytische Chemie Albert-Ludwigs-Universität Freiburg Albertstraße 21 79104 Freiburg i.Br. Germany
| | - Ingo Krossing
- Institut für anorganische und analytische Chemie Albert-Ludwigs-Universität Freiburg Albertstraße 21 79104 Freiburg i.Br. Germany
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Grams S, Eyselein J, Langer J, Färber C, Harder S. Boosting Low-Valent Aluminum(I) Reactivity with a Potassium Reagent. Angew Chem Int Ed Engl 2020; 59:15982-15986. [PMID: 32449816 PMCID: PMC7540686 DOI: 10.1002/anie.202006693] [Citation(s) in RCA: 90] [Impact Index Per Article: 22.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2020] [Indexed: 12/11/2022]
Abstract
The reagent RK [R=CH(SiMe3 )2 or N(SiMe3 )2 ] was expected to react with the low-valent (DIPP BDI)Al (DIPP BDI=HC[C(Me)N(DIPP)]2 , DIPP=2,6-iPr-phenyl) to give [(DIPP BDI)AlR]- K+ . However, deprotonation of the Me group in the ligand backbone was observed and [H2 C=C(N-DIPP)-C(H)=C(Me)-N-DIPP]Al- K+ (1) crystallized as a bright-yellow product (73 %). Like most anionic AlI complexes, 1 forms a dimer in which formally negatively charged Al centers are bridged by K+ ions, showing strong K+ ⋅⋅⋅DIPP interactions. The rather short Al-K bonds [3.499(1)-3.588(1) Å] indicate tight bonding of the dimer. According to DOSY NMR analysis, 1 is dimeric in C6 H6 and monomeric in THF, but slowly reacts with both solvents. In reaction with C6 H6 , two C-H bond activations are observed and a product with a para-phenylene moiety was exclusively isolated. DFT calculations confirm that the Al center in 1 is more reactive than that in (DIPP BDI)Al. Calculations show that both AlI and K+ work in concert and determines the reactivity of 1.
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Affiliation(s)
- Samuel Grams
- Chair of Inorganic and Organometallic ChemistryUniversität Erlangen-NürnbergEgerlandstrasse 191058ErlangenGermany
| | - Jonathan Eyselein
- Chair of Inorganic and Organometallic ChemistryUniversität Erlangen-NürnbergEgerlandstrasse 191058ErlangenGermany
| | - Jens Langer
- Chair of Inorganic and Organometallic ChemistryUniversität Erlangen-NürnbergEgerlandstrasse 191058ErlangenGermany
| | - Christian Färber
- Chair of Inorganic and Organometallic ChemistryUniversität Erlangen-NürnbergEgerlandstrasse 191058ErlangenGermany
| | - Sjoerd Harder
- Chair of Inorganic and Organometallic ChemistryUniversität Erlangen-NürnbergEgerlandstrasse 191058ErlangenGermany
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Obi AD, Walley JE, Frey NC, Wong YO, Dickie DA, Webster CE, Gilliard RJ. Tris(carbene) Stabilization of Monomeric Magnesium Cations: A Neutral, Nontethered Ligand Approach. Organometallics 2020. [DOI: 10.1021/acs.organomet.0c00462] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Akachukwu D. Obi
- Department of Chemistry, University of Virginia, 409 McCormick Road, PO Box 400319, Charlottesville, Virginia 22904, United States
| | - Jacob E. Walley
- Department of Chemistry, University of Virginia, 409 McCormick Road, PO Box 400319, Charlottesville, Virginia 22904, United States
| | - Nathan C. Frey
- Department of Chemistry, Mississippi State University, Box 9573, Mississippi State, Mississippi 39762, United States
| | - Yuen Onn Wong
- Department of Chemistry, University of Virginia, 409 McCormick Road, PO Box 400319, Charlottesville, Virginia 22904, United States
| | - Diane A. Dickie
- Department of Chemistry, University of Virginia, 409 McCormick Road, PO Box 400319, Charlottesville, Virginia 22904, United States
| | - Charles Edwin Webster
- Department of Chemistry, Mississippi State University, Box 9573, Mississippi State, Mississippi 39762, United States
| | - Robert J. Gilliard
- Department of Chemistry, University of Virginia, 409 McCormick Road, PO Box 400319, Charlottesville, Virginia 22904, United States
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27
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Grams S, Eyselein J, Langer J, Färber C, Harder S. Boosting Low‐Valent Aluminum(I) Reactivity with a Potassium Reagent. Angew Chem Int Ed Engl 2020. [DOI: 10.1002/ange.202006693] [Citation(s) in RCA: 41] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Samuel Grams
- Chair of Inorganic and Organometallic Chemistry Universität Erlangen-Nürnberg Egerlandstrasse 1 91058 Erlangen Germany
| | - Jonathan Eyselein
- Chair of Inorganic and Organometallic Chemistry Universität Erlangen-Nürnberg Egerlandstrasse 1 91058 Erlangen Germany
| | - Jens Langer
- Chair of Inorganic and Organometallic Chemistry Universität Erlangen-Nürnberg Egerlandstrasse 1 91058 Erlangen Germany
| | - Christian Färber
- Chair of Inorganic and Organometallic Chemistry Universität Erlangen-Nürnberg Egerlandstrasse 1 91058 Erlangen Germany
| | - Sjoerd Harder
- Chair of Inorganic and Organometallic Chemistry Universität Erlangen-Nürnberg Egerlandstrasse 1 91058 Erlangen Germany
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28
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Martin J, Eyselein J, Grams S, Harder S. Hydrogen Isotope Exchange with Superbulky Alkaline Earth Metal Amide Catalysts. ACS Catal 2020. [DOI: 10.1021/acscatal.0c01359] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Affiliation(s)
- Johannes Martin
- Inorganic and Organometallic Chemistry, Universität Erlangen-Nürnberg, Egerlandstrasse 1, 91058 Erlangen, Germany
| | - Jonathan Eyselein
- Inorganic and Organometallic Chemistry, Universität Erlangen-Nürnberg, Egerlandstrasse 1, 91058 Erlangen, Germany
| | - Samuel Grams
- Inorganic and Organometallic Chemistry, Universität Erlangen-Nürnberg, Egerlandstrasse 1, 91058 Erlangen, Germany
| | - Sjoerd Harder
- Inorganic and Organometallic Chemistry, Universität Erlangen-Nürnberg, Egerlandstrasse 1, 91058 Erlangen, Germany
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Naglav-Hansen D, Dzialkowski K, Tobey B, Wölper C, Jansen G, Schulz S. Hungry for charge – how a beryllium scorpionate complex “eats” a weakly coordinating anion. ZEITSCHRIFT FUR NATURFORSCHUNG SECTION B-A JOURNAL OF CHEMICAL SCIENCES 2020. [DOI: 10.1515/znb-2020-0034] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Abstract
We present the reaction of a tris(pyrazolyl) beryllium scorpionate (TpBe) complex with a weakly coordinating anion (WCA), which yields the heteroleptic complex TpBeOC(CF3)3
1 (TpBeOR
F). The product 1 has been characterized by multinuclear NMR spectroscopy (1H, 9Be, 13C) and single-crystal X-ray diffraction (scXRD). Quantum chemical calculations (DFT, NPA, LOL) were performed to study the bonding nature in 1.
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Affiliation(s)
- Dominik Naglav-Hansen
- Institute of Inorganic Chemistry, University of Tübingen , Auf der Morgenstelle 18 , D- 72076 Tübingen , Germany
| | - Kevin Dzialkowski
- Faculty of Chemistry , University of Duisburg-Essen , Universitätsstraße 7, S07S03C30 , D-45141 Essen , Germany
| | - Briac Tobey
- Faculty of Chemistry , University of Duisburg-Essen , Universitätsstraße 7, S07S03C30 , D-45141 Essen , Germany
| | - Christoph Wölper
- Faculty of Chemistry , University of Duisburg-Essen , Universitätsstraße 7, S07S03C30 , D-45141 Essen , Germany
| | - Georg Jansen
- Faculty of Chemistry , University of Duisburg-Essen , Universitätsstraße 7, S07S03C30 , D-45141 Essen , Germany
| | - Stephan Schulz
- Faculty of Chemistry and Center for NanoIntegration (Cenide) , University of Duisburg-Essen , Universitätsstraße 7, S07S03C30 , D-45141 Essen , Germany , Fax: +49-201-18-33830,
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Brand S, Causero A, Elsen H, Pahl J, Langer J, Harder S. Ligand Effects in Calcium Catalyzed Ketone Hydroboration. Eur J Inorg Chem 2020. [DOI: 10.1002/ejic.202000264] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Affiliation(s)
- Steffen Brand
- Inorganic and Organometallic Chemistry University Erlangen‐Nürnberg Egerlandstrasse 1 91058 Erlangen Germany
| | - Andrea Causero
- Inorganic and Organometallic Chemistry University Erlangen‐Nürnberg Egerlandstrasse 1 91058 Erlangen Germany
| | - Holger Elsen
- Inorganic and Organometallic Chemistry University Erlangen‐Nürnberg Egerlandstrasse 1 91058 Erlangen Germany
| | - Jürgen Pahl
- Inorganic and Organometallic Chemistry University Erlangen‐Nürnberg Egerlandstrasse 1 91058 Erlangen Germany
| | - Jens Langer
- Inorganic and Organometallic Chemistry University Erlangen‐Nürnberg Egerlandstrasse 1 91058 Erlangen Germany
| | - Sjoerd Harder
- Inorganic and Organometallic Chemistry University Erlangen‐Nürnberg Egerlandstrasse 1 91058 Erlangen Germany
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31
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Schorpp M, Krossing I. Soft interactions with hard Lewis acids: generation of mono- and dicationic alkaline-earth metal arene-complexes by direct oxidation. Chem Sci 2020; 11:2068-2076. [PMID: 32180929 PMCID: PMC7057851 DOI: 10.1039/c9sc06254h] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2019] [Accepted: 01/12/2020] [Indexed: 12/26/2022] Open
Abstract
The synthesis of the first unsupported dicationic arene complexes of calcium and strontium [(η6-HMB)AE(oDFB)4]2+ is reported (HMB = hexamethylbenzene; AE = alkaline earth metal; oDFB = ortho-difluorobenzene). They were prepared by direct oxidation of the elemental metals employing the ligand-forming radical cation salt [HMB][WCA] as an oxidant (WCA = [Al(ORF)4] or [μF-{Al(ORF)3}2]; RF = C(CF3)3). In addition, monocationic η6-HMB complexes of calcium, strontium and barium supported by coordination of the monodentate anion [F-Al(ORF)3]- are reported. In all examples, almost undistorted η6-HMB coordination is observed with rather short M-arenecentroid distances approaching those observed with the isoelectronic but negatively charged pentamethylcyclopentadienyl ligand. The structure and bonding, thermodynamic stability and Lewis acidity (fluoride/hydride ion affinities, FIA/HIA) of the generated complexes were assessed by DFT methods. It followed that the gaseous dications [(η6-HMB)AE(oDFB)4]2+ are extremely hard Lewis acids that retain FIAs close to superacidity in solution.
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Affiliation(s)
- Marcel Schorpp
- Institut für Anorganische und Analytische Chemie , Freiburger Materialforschungszentrum (FMF) , Universität Freiburg , Albertstr. 21 , 79104 Freiburg , Germany .
| | - Ingo Krossing
- Institut für Anorganische und Analytische Chemie , Freiburger Materialforschungszentrum (FMF) , Universität Freiburg , Albertstr. 21 , 79104 Freiburg , Germany .
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32
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Lawrence SR, Ohlin CA, Cordes DB, Slawin AMZ, Stasch A. Hydrocarbon-soluble, hexaanionic fulleride complexes of magnesium. Chem Sci 2019; 10:10755-10764. [PMID: 32055382 PMCID: PMC6993810 DOI: 10.1039/c9sc03857d] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2019] [Accepted: 10/06/2019] [Indexed: 11/21/2022] Open
Abstract
Fullerene C60 reacts with dimagnesium(i) compounds LMgMgL, where L is a monoanionic β-diketiminate ligand, to contact ion complexes [(LMg)nC60], where n is predominantly 2, 4 or 6.
The reaction of the magnesium(i) complexes [{(Arnacnac)Mg}2], (Arnacnac = HC(MeCNAr)2, Ar = Dip (2,6-iPr2C6H3), Dep (2,6-Et2C6H3), Mes (2,4,6-Me3C6H2), Xyl (2,6-Me2C6H3)) with fullerene C60 afforded a series of hydrocarbon-soluble fulleride complexes [{(Arnacnac)Mg}nC60], predominantly with n = 6, 4 and 2. 13C{1H} NMR spectroscopic studies show both similarities (n = 6) and differences (n = 4, 2) to previously characterised examples of fulleride complexes and materials with electropositive metal ions. The molecular structures of [{(Arnacnac)Mg}nC60] with n = 6, 4 and 2 can be described as inverse coordination complexes of n [(Arnacnac)Mg]+ ions with C60n– anions showing predominantly ionic metal–ligand interactions, and include the first well-defined and soluble complexes of the C606– ion. Experimental studies show the flexible ionic nature of the {(Arnacnac)Mg}+···C606– coordination bonds. DFT calculations on the model complex [{(Menacnac)Mg}6C60] (Menacnac = HC(MeCNMe)2) support the formulation as an ionic complex with a central C606– anion and comparable frontier orbitals to C606– with a small HOMO–LUMO gap. The reduction of C60 to its hexaanion gives an indication about the reducing strength of dimagnesium(i) complexes.
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Affiliation(s)
- Samuel R Lawrence
- EaStCHEM School of Chemistry , University of St Andrews , North Haugh , St Andrews , KY16 9ST , UK .
| | - C André Ohlin
- Department of Chemistry , Umeå University , Linnaeus väg 10 , Umeå , 907 36 , Sweden
| | - David B Cordes
- EaStCHEM School of Chemistry , University of St Andrews , North Haugh , St Andrews , KY16 9ST , UK .
| | - Alexandra M Z Slawin
- EaStCHEM School of Chemistry , University of St Andrews , North Haugh , St Andrews , KY16 9ST , UK .
| | - Andreas Stasch
- EaStCHEM School of Chemistry , University of St Andrews , North Haugh , St Andrews , KY16 9ST , UK .
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33
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Gauld RM, McLellan R, Kennedy AR, Barker J, Reid J, Mulvey RE. Backbone Reactivity of Lithium β-Diketiminate (NacNac) Complexes with CO 2 , tBuNCO and iPrNCO. Chemistry 2019; 25:14728-14734. [PMID: 31574177 DOI: 10.1002/chem.201904013] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2019] [Revised: 09/27/2019] [Indexed: 01/07/2023]
Abstract
Though alkali metal NacNac (β-diketiminate) complexes have been utilised in synthesis as NacNac-transfer agents, studies of them in their own right with small molecules are exceptionally rare. Here, the lithium compound of the common 2,6-diisopropylphenyl-β-methyldiketiminate [NacNac(Dipp, Me)] ligand is investigated with carbon dioxide and isocyanates. In all four cases reaction occurs at the backbone γ-C atom of the NacNac ligand, which redistributes electronically into a diimine. Insertion of CO2 gives an eight-atom carboxylate (Li2 O4 C2 ) ring at the γ-C site in a dimer. Insertion of tBuNCO gives a secondary amide at the γ-C site in a monomer with TMEDA chelating lithium. Double insertion of tBuNCO and (adventitious) oxygen gives a dimer with a (LiO)2 central core involving the latter source. Insertion of less bulky (iPrNCO) gives a dimer with dimerisation through the C=O bonds of the emergent secondary amide function.
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Affiliation(s)
- Richard M Gauld
- WestCHEM, Department of Pure and Applied Chemistry, University of Strathclyde, Glasgow, G1 1XL, UK
| | - Ross McLellan
- WestCHEM, Department of Pure and Applied Chemistry, University of Strathclyde, Glasgow, G1 1XL, UK
| | - Alan R Kennedy
- WestCHEM, Department of Pure and Applied Chemistry, University of Strathclyde, Glasgow, G1 1XL, UK
| | - Jim Barker
- Innospec Ltd, Innospec Manufacturing Park, Oil Sites Road, Ellesmere Port, Cheshire, CH65 4EY, UK
| | - Jacqueline Reid
- Innospec Ltd, Innospec Manufacturing Park, Oil Sites Road, Ellesmere Port, Cheshire, CH65 4EY, UK
| | - Robert E Mulvey
- WestCHEM, Department of Pure and Applied Chemistry, University of Strathclyde, Glasgow, G1 1XL, UK
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Abstract
Recently, we have witnessed significant progress with regard to the synthesis of molecular alkaline earth metal reagents and catalysts. To provide new precursors for light alkaline earth metal chemistry, molecular aryloxide and alkoxide complexes of beryllium and magnesium are reported. The reaction of beryllium chloride dietherate with two equivalents of 1,3-diisopropyl-4,5-dimethylimidizol-2-ylidine (sIPr) results in the formation of a bis(N-heterocyclic carbene) (NHC) beryllium dichloride complex, (sIPr)2BeCl2 (1). Compound 1 reacts with lithium diisopropylphenoxide (LiODipp) or sodium ethoxide (NaOEt) to form the terminal aryloxide (sIPr)Be(ODipp)2 (2) and alkoxide dimer [(sIPr)Be(OEt)Cl]2 (3), respectively. Compounds 2 and 3 represent the first beryllium alkoxide and aryloxide species supported by NHCs. Structurally related dimers of magnesium, [(sIPr)Mg(OEt)Brl]2 (4) and [(sIPr)Mg(OEt)Me]2 (5), were also prepared. Compounds 1-5 were characterized by single crystal X-ray diffraction studies, 1H, 13C, and 9Be NMR spectroscopy where applicable.
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Affiliation(s)
- Lucia Garcia
- Department of Chemistry, University of Bath, Claverton Down, Bath BA2 7AY, U.K
| | - Mary F. Mahon
- Department of Chemistry, University of Bath, Claverton Down, Bath BA2 7AY, U.K
| | - Michael S. Hill
- Department of Chemistry, University of Bath, Claverton Down, Bath BA2 7AY, U.K
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36
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Freeman LA, Walley JE, Obi AD, Wang G, Dickie DA, Molino A, Wilson DJD, Gilliard RJ. Stepwise Reduction at Magnesium and Beryllium: Cooperative Effects of Carbenes with Redox Non-Innocent α-Diimines. Inorg Chem 2019; 58:10554-10568. [PMID: 31124671 DOI: 10.1021/acs.inorgchem.9b01058] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
In the past two decades, the organometallic chemistry of the alkaline earth elements has experienced a renaissance due in part to developments in ligand stabilization strategies. In order to expand the scope of redox chemistry known for magnesium and beryllium, we have synthesized a set of reduced magnesium and beryllium complexes and compared their resulting structural and electronic properties. The carbene-coordinated alkaline earth-halides, (Et2CAAC)MgBr2 (1), (SIPr)MgBr2 (2), (Et2CAAC)BeCl2 (3), and (SIPr)BeCl2 (4) [Et2CAAC = diethyl cyclic(alkyl)(amino) carbene; SIPr = 1,3-bis(2,6-diisopropylphenyl)-4,5-dihydroimidazole-2-ylidene] were combined with an α-diimine [2,2-bipyridine (bpy) or bis(2,6-diisopropylphenyl)-1,4-diazabutadiene (DippDAB)] and the appropriate stoichiometric amount of potassium graphite to form singly- and doubly-reduced compounds (Et2CAAC)MgBr(DippDAB) (5), (Et2CAAC)MgBr(bpy) (6), (Et2CAAC)Mg(DippDAB) (7), (Et2CAAC)Be(bpy) (8), and (SIPr)Be(bpy) (9). The doubly-reduced compounds 7-9 exhibit substantial π-bonding interactions across the diimine core, metal center, and π-acidic carbene. Each complex was fully characterized by UV-vis, FT-IR, X-ray crystallography, 1H, 13C, and 9Be NMR, or EPR where applicable. We use these compounds to highlight the differences in the organometallic chemistry of the lightest alkaline earth metals, magnesium and beryllium, in an otherwise identical chemical environment.
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Affiliation(s)
- Lucas A Freeman
- Department of Chemistry , University of Virginia , 409 McCormick Road , PO Box 400319, Charlottesville , Virginia 22904 , United States
| | - Jacob E Walley
- Department of Chemistry , University of Virginia , 409 McCormick Road , PO Box 400319, Charlottesville , Virginia 22904 , United States
| | - Akachukwu D Obi
- Department of Chemistry , University of Virginia , 409 McCormick Road , PO Box 400319, Charlottesville , Virginia 22904 , United States
| | - Guocang Wang
- Department of Chemistry , University of Virginia , 409 McCormick Road , PO Box 400319, Charlottesville , Virginia 22904 , United States
| | - Diane A Dickie
- Department of Chemistry , University of Virginia , 409 McCormick Road , PO Box 400319, Charlottesville , Virginia 22904 , United States
| | - Andrew Molino
- Department of Chemistry and Physics, La Trobe Institute for Molecular Science , La Trobe University , Bundoora , Victoria 3083 , Australia
| | - David J D Wilson
- Department of Chemistry and Physics, La Trobe Institute for Molecular Science , La Trobe University , Bundoora , Victoria 3083 , Australia
| | - Robert J Gilliard
- Department of Chemistry , University of Virginia , 409 McCormick Road , PO Box 400319, Charlottesville , Virginia 22904 , United States
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Bruyere JC, Gourlaouen C, Karmazin L, Bailly C, Boudon C, Ruhlmann L, de Frémont P, Dagorne S. Synthesis and Characterization of Neutral and Cationic Magnesium Complexes Supported by NHC Ligands. Organometallics 2019. [DOI: 10.1021/acs.organomet.9b00304] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Jean-Charles Bruyere
- Institut de Chimie de Strasbourg, CNRS-Université de Strasbourg, 1 rue Blaise Pascal, 67000 Strasbourg, France
| | - Christophe Gourlaouen
- Institut de Chimie de Strasbourg, CNRS-Université de Strasbourg, 1 rue Blaise Pascal, 67000 Strasbourg, France
| | - Lydia Karmazin
- Service de Radiocristallographie-Fédération de Chimie Le Bel, FR2010-1 rue Blaise Pascal, BP296/R8, 67008 Strasbourg Cedex, France
| | - Corinne Bailly
- Service de Radiocristallographie-Fédération de Chimie Le Bel, FR2010-1 rue Blaise Pascal, BP296/R8, 67008 Strasbourg Cedex, France
| | - Corinne Boudon
- Institut de Chimie de Strasbourg, CNRS-Université de Strasbourg, 1 rue Blaise Pascal, 67000 Strasbourg, France
| | - Laurent Ruhlmann
- Institut de Chimie de Strasbourg, CNRS-Université de Strasbourg, 1 rue Blaise Pascal, 67000 Strasbourg, France
| | - Pierre de Frémont
- Institut de Chimie de Strasbourg, CNRS-Université de Strasbourg, 1 rue Blaise Pascal, 67000 Strasbourg, France
| | - Samuel Dagorne
- Institut de Chimie de Strasbourg, CNRS-Université de Strasbourg, 1 rue Blaise Pascal, 67000 Strasbourg, France
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38
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Banerjee S, Ankur, Andrews AP, Varghese B, Venugopal A. Amidomagnesium cations. Dalton Trans 2019; 48:7313-7319. [PMID: 30806382 DOI: 10.1039/c8dt05095c] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
We report the synthesis, structure and reactivity of molecular amidomagnesium cations bearing tris{2-(dimethylamino)-ethyl}amine (Me6TREN). Me6TREN binds to the cationic magnesium centre exhibiting κ4 and κ3 coordination modes in [Me6TREN-Mg-N(SiHMe2)2]+ and [Me6TREN-Mg-N(SiMe3)2]+ respectively. [Me6TREN-Mg-N(SiHMe2)2]+ reacts with benzophenone resulting in the insertion of the carbonyl group across β-SiH bond. The reaction between [Me6TREN-Mg-N(SiMe3)2]+ and CO2 leads to [Me6TREN-Mg-OSiMe3]+, while the reaction with H2O results in [Me6TREN-Mg-OH]22+. Attempts to prepare hydridomagnesium cations from [Me6TREN-Mg-N(SiMe3)2]+ using KH resulted in the precipitation of MgH2 and the isolation of [(Me6TREN)K(THF)3]+.
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Affiliation(s)
- Sumanta Banerjee
- School of Chemistry, Indian Institute of Science Education and Research Thiruvananthapuram, Vithura, Thiruvananthapuram 695551, India.
| | - Ankur
- School of Chemistry, Indian Institute of Science Education and Research Thiruvananthapuram, Vithura, Thiruvananthapuram 695551, India.
| | - Alex P Andrews
- School of Chemistry, Indian Institute of Science Education and Research Thiruvananthapuram, Vithura, Thiruvananthapuram 695551, India.
| | - Babu Varghese
- Sophisticated Analytical Instrument Facility, Indian Institute of Technology Madras, Chennai 600036, India
| | - Ajay Venugopal
- School of Chemistry, Indian Institute of Science Education and Research Thiruvananthapuram, Vithura, Thiruvananthapuram 695551, India.
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39
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Friedrich A, Pahl J, Elsen H, Harder S. Bulky cationic β-diketiminate magnesium complexes. Dalton Trans 2019; 48:5560-5568. [PMID: 30566138 DOI: 10.1039/c8dt03576h] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Cationic β-diketiminate Mg complexes with the bulky tBuBDI ligand and the weakly coordinating anion B(C6F5)4- have been prepared by the reaction of (tBuBDI)MgnBu with [Ph3C]+[B(C6F5)4]-; tBuBDI = CH[C(tBu)N-Dipp]2 and Dipp = 2,6-diisopropylphenyl. Their structures are compared to the previously reported cationic (MeBDI)Mg+ complexes; MeBDI = CH[C(Me)N-Dipp]2. Crystallization of [(tBuBDI)Mg]+[B(C6F5)4]- from chlorobenzene gave a unique (tBuBDI)Mg+·ClC6H5 cation with a rather short MgCl and consequently long C-Cl bond. Crystallization from chlorobenzene/arene solvent mixtures gave (tBuBDI)Mg+·arene complexes (arene = benzene, toluene, m-xylene) but in the presence of mesitylene the chlorobenzene complex was formed. Due to the greater shielding of the metal, none of these complexes display Mg(F5C6)4B- interactions. Crystal structures of the arene complexes show in all cases η2-coordination of the arene ligands. Ring slippage from a more favorable η2-coordination can be explained by the steric bulk of the tBuBDI ligand. The smaller arenes, benzene and toluene, also bind to (tBuBDI)Mg+ in bromobenzene solution. The Lewis acidity of these cationic Mg complexes was determined by the Gutmann-Beckett test. The acceptor number for (tBuBDI)Mg+ (AN = 76.0) is substantially higher than that estimated for (MeBDI)Mg+ (AN = 70.3). Calculation of the atomic NPA charges by DFT shows that the Mg2+ ion in (tBuBDI)Mg+ is slightly more positively charged than the metal in (MeBDI)Mg+, confirming its higher Lewis acidity. The lower benzene complexation energy calculated for (tBuBDI)Mg+versus (MeBDI)Mg+ is due to steric congestion of the metal in the (tBuBDI)Mg+ cation which allows only for Mg(η1)C6H6 instead of Mg(η6)C6H6 bonding. This ring slippage, however, results in a significant polarization of the electron density in the benzene ring, making it susceptible for nucleophilic attack.
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Affiliation(s)
- Alexander Friedrich
- Inorganic and Organometallic Chemistry, Friedrich-Alexander-Universität Erlangen-Nürnberg, Egerlandstraße 1, 91058 Erlangen, Germany.
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41
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Pietrzak T, Justyniak I, Park JV, Terlecki M, Kapuśniak Ł, Lewiński J. Reaching Milestones in the Oxygenation Chemistry of Magnesium Alkyls: towards Intimate States of O
2
Activation and the First Monomeric Well‐Defined Magnesium Alkylperoxide. Chemistry 2019; 25:2503-2510. [DOI: 10.1002/chem.201805180] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2018] [Revised: 12/04/2018] [Indexed: 01/09/2023]
Affiliation(s)
- Tomasz Pietrzak
- Faculty of ChemistryWarsaw University of Technology Noakowskiego 3 00-664 Warsaw Poland
| | - Iwona Justyniak
- Institute of Physical ChemistryPolish Academy of Science Kasprzaka 44/52 01-224 Warsaw Poland
| | - Jiwon Victoria Park
- Department of ChemistryMassachusetts Institute of Technology 77 Massachusetts Avenue Cambridge Massachusetts 02139 USA
| | - Michał Terlecki
- Faculty of ChemistryWarsaw University of Technology Noakowskiego 3 00-664 Warsaw Poland
| | - Łukasz Kapuśniak
- Faculty of ChemistryWarsaw University of Technology Noakowskiego 3 00-664 Warsaw Poland
| | - Janusz Lewiński
- Faculty of ChemistryWarsaw University of Technology Noakowskiego 3 00-664 Warsaw Poland
- Institute of Physical ChemistryPolish Academy of Science Kasprzaka 44/52 01-224 Warsaw Poland
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42
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Pahl J, Stennett TE, Volland M, Guldi DM, Harder S. Complexation and Versatile Reactivity of a Highly Lewis Acidic Cationic Mg Complex with Alkynes and Phosphines. Chemistry 2019; 25:2025-2034. [DOI: 10.1002/chem.201804802] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2018] [Revised: 10/17/2018] [Indexed: 01/21/2023]
Affiliation(s)
- Jürgen Pahl
- Inorganic and Organometallic Chemistry; Friedrich-Alexander-Universität Erlangen-Nürnberg; Egerlandstraße 1 91058 Erlangen Germany
| | - Tom E. Stennett
- Inorganic and Organometallic Chemistry; Friedrich-Alexander-Universität Erlangen-Nürnberg; Egerlandstraße 1 91058 Erlangen Germany
| | - Michel Volland
- Department of Chemistry and Pharmacy & Interdisciplinary Center for, Molecular Materials (ICMM); Friedrich-Alexander-Universität Erlangen-Nürnberg; Egerlandstraße 3 91058 Erlangen Germany
| | - Dirk M. Guldi
- Department of Chemistry and Pharmacy & Interdisciplinary Center for, Molecular Materials (ICMM); Friedrich-Alexander-Universität Erlangen-Nürnberg; Egerlandstraße 3 91058 Erlangen Germany
| | - Sjoerd Harder
- Inorganic and Organometallic Chemistry; Friedrich-Alexander-Universität Erlangen-Nürnberg; Egerlandstraße 1 91058 Erlangen Germany
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43
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Morris LJ, Hill MS, Manners I, McMullin CL, Mahon MF, Rajabi NA. Calcium stannyl formation by organostannane dehydrogenation. Chem Commun (Camb) 2019; 55:12964-12967. [DOI: 10.1039/c9cc07289f] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Reaction of the dimeric calcium hydride, [(BDI)CaH]2 (1), with Ph3SnH ensues with elimination of H2 to provide [(BDI)Ca-μ2-H-(SnPh3)Ca(BDI)] (3) and [(BDI)Ca(SnPh3)]2 (4) alongside dismutation to Ph4Sn, H2 and Sn(0).
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Affiliation(s)
- Louis J. Morris
- Department of Chemistry
- University of Bath
- Claverton Down
- Bath
- UK
| | - Michael S. Hill
- Department of Chemistry
- University of Bath
- Claverton Down
- Bath
- UK
| | - Ian Manners
- Department of Chemistry
- University of Victoria
- Victoria
- Canada
| | | | - Mary F. Mahon
- Department of Chemistry
- University of Bath
- Claverton Down
- Bath
- UK
| | - Nasir A. Rajabi
- Department of Chemistry
- University of Bath
- Claverton Down
- Bath
- UK
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44
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Fischer CA, Rösch A, Elsen H, Ballmann G, Wiesinger M, Langer J, Färber C, Harder S. Lewis acidic alkaline earth metal complexes with a perfluorinated diphenylamide ligand. Dalton Trans 2019; 48:6757-6766. [DOI: 10.1039/c9dt01272a] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Alkaline earth metal chemistry with the anion [N(C6F5)2]− has been explored. Complexes are stabilized by metal⋯F interactions. Mg[N(C6F5)2]2 is a stronger Lewis acid than B(C6F5)3.
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Affiliation(s)
- Christian A. Fischer
- Inorganic and Organometallic Chemistry
- Friedrich-Alexander-Universität Erlangen-Nürnberg
- 91058 Erlangen
- Germany
| | - Andreas Rösch
- Inorganic and Organometallic Chemistry
- Friedrich-Alexander-Universität Erlangen-Nürnberg
- 91058 Erlangen
- Germany
| | - Holger Elsen
- Inorganic and Organometallic Chemistry
- Friedrich-Alexander-Universität Erlangen-Nürnberg
- 91058 Erlangen
- Germany
| | - Gerd Ballmann
- Inorganic and Organometallic Chemistry
- Friedrich-Alexander-Universität Erlangen-Nürnberg
- 91058 Erlangen
- Germany
| | - Michael Wiesinger
- Inorganic and Organometallic Chemistry
- Friedrich-Alexander-Universität Erlangen-Nürnberg
- 91058 Erlangen
- Germany
| | - Jens Langer
- Inorganic and Organometallic Chemistry
- Friedrich-Alexander-Universität Erlangen-Nürnberg
- 91058 Erlangen
- Germany
| | - Christian Färber
- Inorganic and Organometallic Chemistry
- Friedrich-Alexander-Universität Erlangen-Nürnberg
- 91058 Erlangen
- Germany
| | - Sjoerd Harder
- Inorganic and Organometallic Chemistry
- Friedrich-Alexander-Universität Erlangen-Nürnberg
- 91058 Erlangen
- Germany
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45
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Brand S, Elsen H, Langer J, Donaubauer WA, Hampel F, Harder S. Facile Benzene Reduction by a Ca2+
/AlI
Lewis Acid/Base Combination. Angew Chem Int Ed Engl 2018. [DOI: 10.1002/ange.201809236] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- Steffen Brand
- Chair of Inorganic and Organometallic Chemistry; Universität Erlangen-Nürnberg; Egerlandstrasse 1 91058 Erlangen Germany
| | - Holger Elsen
- Chair of Inorganic and Organometallic Chemistry; Universität Erlangen-Nürnberg; Egerlandstrasse 1 91058 Erlangen Germany
| | - Jens Langer
- Chair of Inorganic and Organometallic Chemistry; Universität Erlangen-Nürnberg; Egerlandstrasse 1 91058 Erlangen Germany
| | - Wolfgang A. Donaubauer
- Chair of Organic Chemistry II; Department of Chemistry & Pharmacy; Universität Erlangen-Nürnberg; Nikolaus-Fiebiger-Straße 10 91058 Erlangen Germany
| | - Frank Hampel
- Chair of Organic Chemistry II; Department of Chemistry & Pharmacy; Universität Erlangen-Nürnberg; Nikolaus-Fiebiger-Straße 10 91058 Erlangen Germany
| | - Sjoerd Harder
- Chair of Inorganic and Organometallic Chemistry; Universität Erlangen-Nürnberg; Egerlandstrasse 1 91058 Erlangen Germany
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46
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Brand S, Elsen H, Langer J, Donaubauer WA, Hampel F, Harder S. Facile Benzene Reduction by a Ca2+
/AlI
Lewis Acid/Base Combination. Angew Chem Int Ed Engl 2018; 57:14169-14173. [DOI: 10.1002/anie.201809236] [Citation(s) in RCA: 60] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2018] [Indexed: 12/20/2022]
Affiliation(s)
- Steffen Brand
- Chair of Inorganic and Organometallic Chemistry; Universität Erlangen-Nürnberg; Egerlandstrasse 1 91058 Erlangen Germany
| | - Holger Elsen
- Chair of Inorganic and Organometallic Chemistry; Universität Erlangen-Nürnberg; Egerlandstrasse 1 91058 Erlangen Germany
| | - Jens Langer
- Chair of Inorganic and Organometallic Chemistry; Universität Erlangen-Nürnberg; Egerlandstrasse 1 91058 Erlangen Germany
| | - Wolfgang A. Donaubauer
- Chair of Organic Chemistry II; Department of Chemistry & Pharmacy; Universität Erlangen-Nürnberg; Nikolaus-Fiebiger-Straße 10 91058 Erlangen Germany
| | - Frank Hampel
- Chair of Organic Chemistry II; Department of Chemistry & Pharmacy; Universität Erlangen-Nürnberg; Nikolaus-Fiebiger-Straße 10 91058 Erlangen Germany
| | - Sjoerd Harder
- Chair of Inorganic and Organometallic Chemistry; Universität Erlangen-Nürnberg; Egerlandstrasse 1 91058 Erlangen Germany
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