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Eickhoff L, Kramer P, Bresien J, Michalik D, Villinger A, Schulz A. On the Dynamic Behavior of Pacman Phosphanes─A Case of Cooperativity and Redox Isomerism. Inorg Chem 2023; 62:6768-6778. [PMID: 37068163 DOI: 10.1021/acs.inorgchem.3c00481] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/19/2023]
Abstract
In solution, the Pacman chlorophosphane (2Cl) shows fast exchange of the endo/exo-orientation of the two P-Cl bonds in the molecule featuring cooperativity. Experimental and quantum mechanical investigations of the inversion on the phosphorus(III) centers reveal a crucial role of chloride ions in the dynamic process. To confirm the results, the homologous Pacman halogen-phosphanes 2X were prepared by halogen exchange reactions (X = F, Br, and I). Besides accelerated dynamic behavior for the heavier analogues, significant differences in the molecular structure are caused by the halogen exchange reactions, including the formation of an endo-endo substituted Pacman fluorophosphane as well as dicationic species by phosphorus halogen bond dissociation. The latter process can be regarded as redox isomerism since two PIII atoms in 2X become PV centers in the dications.
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Affiliation(s)
- Liesa Eickhoff
- Institut für Chemie, Universität Rostock, Albert-Einstein-Straße 3a, D-18059 Rostock, Germany
| | - Pascal Kramer
- Institut für Chemie, Universität Rostock, Albert-Einstein-Straße 3a, D-18059 Rostock, Germany
| | - Jonas Bresien
- Institut für Chemie, Universität Rostock, Albert-Einstein-Straße 3a, D-18059 Rostock, Germany
| | - Dirk Michalik
- Institut für Chemie, Universität Rostock, Albert-Einstein-Straße 3a, D-18059 Rostock, Germany
- Leibniz-Institut für Katalyse e.V., Albert-Einstein-Straße 29a, D-18059 Rostock, Germany
| | - Alexander Villinger
- Institut für Chemie, Universität Rostock, Albert-Einstein-Straße 3a, D-18059 Rostock, Germany
| | - Axel Schulz
- Institut für Chemie, Universität Rostock, Albert-Einstein-Straße 3a, D-18059 Rostock, Germany
- Leibniz-Institut für Katalyse e.V., Albert-Einstein-Straße 29a, D-18059 Rostock, Germany
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Zechovský J, Kertész E, Erben M, Jambor R, Růžička A, Benkö Z, Dostál L. Oxidations of N-coordinated Arsinidene and Stibinidene by Substituted Quinones: A Remarkable Follow-Up Reactivity. Chempluschem 2023; 88:e202300018. [PMID: 36756773 DOI: 10.1002/cplu.202300018] [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: 01/10/2023] [Revised: 02/07/2023] [Accepted: 02/08/2023] [Indexed: 02/10/2023]
Abstract
The reactivity of pnictinidenes [2-(DippN=CH)-6-(DippNHCH2 )C6 H3 ]E (where E=As (1) or Sb (2)) toward substituted ortho- and para-quinones is reported. The central pnictogen atom is easily oxidized by ortho-quinones closing five-membered EO2 C2 ring. The oxidized antimony derivatives are stable species, while in the case of arsenic compounds the hydrogen of the pendant amino NHCH2 group cleaves one newly formed As-O bonds leading to the closure of a new azaarsole ring. Furthermore, a heating of these arsenic heterocycles resulted in a C-H bond activation at the NCH2 group involved in this heterocycle followed by a reductive elimination of corresponding catechols and arsinidene [2,6-(DippN=CH)C6 H3 ]As. Using of para-quinones, resulted in the oxidation of the central atom with a concomitant hydrogen migration from NHCH2 group even in the case of the antimony derivatives. The reductive elimination of hydroquinones is in this case feasible for all compounds. Studied compounds were characterized by multi-nuclear NMR, IR and Raman spectroscopy and single-crystal X-ray diffraction analysis. The theoretical study focusing the key compounds and reactions is also included.
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Affiliation(s)
- Jan Zechovský
- Department of General and Inorganic Chemistry FCHT, University of Pardubice, Studentská 573, Pardubice, 532 10, Czech Republic
| | - Erik Kertész
- Department of Inorganic and Analytical Chemistry, Budapest University of Technology and Economics, Szent Gellért tér 4, 1111, Budapest, Hungary
| | - Milan Erben
- Department of General and Inorganic Chemistry FCHT, University of Pardubice, Studentská 573, Pardubice, 532 10, Czech Republic
| | - Roman Jambor
- Department of General and Inorganic Chemistry FCHT, University of Pardubice, Studentská 573, Pardubice, 532 10, Czech Republic
| | - Aleš Růžička
- Department of General and Inorganic Chemistry FCHT, University of Pardubice, Studentská 573, Pardubice, 532 10, Czech Republic
| | - Zoltán Benkö
- Department of Inorganic and Analytical Chemistry, Budapest University of Technology and Economics, Szent Gellért tér 4, 1111, Budapest, Hungary
| | - Libor Dostál
- Department of General and Inorganic Chemistry FCHT, University of Pardubice, Studentská 573, Pardubice, 532 10, Czech Republic
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Nieto CI, Sanz D, Claramunt RM, Alkorta I, Elguero J. Pyrazaboles and pyrazolylboranes. Coord Chem Rev 2022. [DOI: 10.1016/j.ccr.2022.214812] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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Gellrich U, Wech F. Hydrogenation of Olefins, Alkynes, Allenes, and Arenes by Borane-Based Frustrated Lewis Pairs. SYNTHESIS-STUTTGART 2022. [DOI: 10.1055/a-1684-5552] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
AbstractIn recent years, borane-based frustrated Lewis pairs have proved to be efficient hydrogenation catalysts and they have become an alternative to transition-metal-based systems. The hydrogen activation by classic FLPs leads to a protonated Lewis base and a borohydride. Consequently, hydrogenations catalyzed by classic FLPs consist of stepwise hydride transfer reactions and protonations (or vice versa). More recently, systems that operate via an initial hydroboration have allowed the substrate scope for FLP-catalyzed hydrogenations to be extended. In this review, hydrogenations of organic substrates catalyzed by borane-based frustrated Lewis pairs are discussed. Emphasis is given to the mechanistic aspects of these catalytic reactions.1 Introduction2 FLP-Catalyzed Hydrogenation of Polarized Double Bonds2.1 Hydrogenation of Michael Acceptors by FLPs2.2 Asymmetric Hydrogenation of Polarized Double Bonds2.3 Hydrogenation of Arenes and N-Heterocycles3 Hydrogenation of Unactivated Olefins and Alkynes3.1 Hydrogenation of Olefins and Alkynes by an Initial Hydroboration4 Summary and Outlook
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Mahaut D, Champagne B, Berionni G. Frustrated Lewis Pair Catalyzed Hydrogenation of Unactivated Alkenes With Sterically Hindered 9‐Phosphatriptycenes. ChemCatChem 2022. [DOI: 10.1002/cctc.202200294] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Damien Mahaut
- University of Namur: Universite de Namur Chemistry BELGIUM
| | | | - Guillaume Berionni
- University of Namur: Universite de Namur Chemistry Department Rue de Bruxelles 61 5000 Namur BELGIUM
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Spielvogel KD, Stumme NC, Fetrow TV, Wang L, Luna JA, Keith JM, Shaw SK, Daly SR. Quantifying Variations in Metal–Ligand Cooperative Binding Strength with Cyclic Voltammetry and Redox-Active Ligands. Inorg Chem 2022; 61:2391-2401. [DOI: 10.1021/acs.inorgchem.1c03014] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Affiliation(s)
- Kyle D. Spielvogel
- Department of Chemistry, The University of Iowa, E331 Chemistry Building, Iowa City, Iowa 52242, United States
| | - Nathan C. Stumme
- Department of Chemistry, The University of Iowa, E331 Chemistry Building, Iowa City, Iowa 52242, United States
| | - Taylor V. Fetrow
- Department of Chemistry, The University of Iowa, E331 Chemistry Building, Iowa City, Iowa 52242, United States
| | - Li Wang
- Department of Chemistry, The University of Iowa, E331 Chemistry Building, Iowa City, Iowa 52242, United States
| | - Javier A. Luna
- Department of Chemistry, The University of Iowa, E331 Chemistry Building, Iowa City, Iowa 52242, United States
| | - Jason M. Keith
- Department of Chemistry, Colgate University, 13 Oak Drive, Hamilton, New York 13346, United States
| | - Scott K. Shaw
- Department of Chemistry, The University of Iowa, E331 Chemistry Building, Iowa City, Iowa 52242, United States
| | - Scott R. Daly
- Department of Chemistry, The University of Iowa, E331 Chemistry Building, Iowa City, Iowa 52242, United States
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Ruppert H, Sigmund LM, Greb L. Calix[4]pyrroles as ligands: recent progress with a focus on the emerging p-block element chemistry. Chem Commun (Camb) 2021; 57:11751-11763. [PMID: 34661225 DOI: 10.1039/d1cc05120b] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Calix[4]pyrroles are readily synthesized in one step from pyrroles and ketones. For several decades, these macrocycles have been exploited as powerful anion receptors or ligands for transition and rare-earth metals. In contrast, calix[4]pyrrolates as ligands for p-block elements were established only in 2018. The present feature article reviews these developments, together with the recent progress on s-, d-, and f-block element complexes of the calix[4]pyrroles. Particular focus is given on the calix[4]pyrrolato aluminate and the corresponding silane, both featuring square planar-coordinated p-block elements in their highest oxidation states. These unique "anti-van't-Hoff-Le-Bel" structures introduce valuable characteristics into main-group element chemistry, such as agostic interactions or ligand-to-metal charge transfer absorptions. The most vital reactivities are highlighted, which rely on properties ranging from amphoterism, redox-activity, and a small HOMO-LUMO gap up to the ability to provide a platform for additional external stimuli. Overall, these developments underscore the beneficial impact of structural constraint of p-block elements and element-ligand cooperativity to enhance the functionality of the most abundant elements in their native oxidation states.
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Affiliation(s)
- Heiko Ruppert
- Anorganisch-Chemisches Institut, Ruprecht-Karls-Universität Heidelberg, Im Neuenheimer Feld 270, 69120 Heidelberg, Germany.
| | - Lukas M Sigmund
- Anorganisch-Chemisches Institut, Ruprecht-Karls-Universität Heidelberg, Im Neuenheimer Feld 270, 69120 Heidelberg, Germany.
| | - Lutz Greb
- Anorganisch-Chemisches Institut, Ruprecht-Karls-Universität Heidelberg, Im Neuenheimer Feld 270, 69120 Heidelberg, Germany.
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Shih DN, Boobalan R, Liu YH, Chein RJ, Chiu CW. [B-Cl-B] + Cations: Chloroborane Masked Chiral Borenium Ions. Inorg Chem 2021; 60:16266-16272. [PMID: 34672549 DOI: 10.1021/acs.inorgchem.1c02073] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
A tricoordinate borenium ion has received considerable attention in recent years for its applications in Lewis acid catalysis. Over the years, asymmetric catalysis mediated by a chiral borenium ion has also been developed. To stabilize the electron-deficient boron atom, a series of chloroborane masked borenium ions featuring the symmetrical [B-Cl-B]+ linkage are prepared and utilized as the catalyst for the enantioselective Diels-Alder cycloaddition of cyclopentadiene and 2,2,2-trifluoroethyl acrylate. The presence of a Cp* ligand is critical in realizing the cyclic diboron compounds, and the stability of the resulting [B-Cl-B]+ cation is dependent on the steric bulkiness of the oxazolidinone moiety. The stereoselectivity of the Diels-Alder cycloaddition is controlled by the substituents of the chiral oxazolidinone ligand and could be further improved via the coordination of SnCl4 at the bridging chloride of the [B-Cl-B]+ cation.
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Affiliation(s)
- Ding-Nan Shih
- Department of Chemistry, National Taiwan University, Taipei 10617, Taiwan
| | | | - Yi-Hung Liu
- Department of Chemistry, National Taiwan University, Taipei 10617, Taiwan
| | - Rong-Jie Chein
- Institute of Chemistry, Academia Sinica, Taipei 11529, Taiwan
| | - Ching-Wen Chiu
- Department of Chemistry, National Taiwan University, Taipei 10617, Taiwan
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Affiliation(s)
- Urs Gellrich
- Institut für Organische Chemie Justus-Liebig-Universität Gießen Heinrich-Buff-Ring-17 35392 Gießen Germany
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Hasenbeck M, Gellrich U. Boron-Ligand Cooperation: The Concept and Applications. Chemistry 2021; 27:5615-5626. [PMID: 33296107 PMCID: PMC8048523 DOI: 10.1002/chem.202004563] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2020] [Revised: 12/02/2020] [Indexed: 11/10/2022]
Abstract
The term boron-ligand cooperation was introduced to describe a specific mode of action by which certain metal-free systems activate chemical bonds. The main characteristic of this mode of action is that one covalently bound substituent at the boron is actively involved in the bond activation process and changes to a datively bound ligand in the course of the bond activation. Within this review, how the term boron-ligand cooperation evolved is reflected on and examples of bond activation by boron-ligand cooperation are discussed. It is furthermore shown that systems that operate via boron-ligand cooperation can complement the reactivity of classic intramolecular frustrated Lewis pairs and applications of this new concept for metal-free catalysis are summarized.
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Affiliation(s)
- Max Hasenbeck
- Institut für Organische ChemieJustus-Liebig-Universität GießenHeinrich-Buff-Ring-1735392GießenGermany
| | - Urs Gellrich
- Institut für Organische ChemieJustus-Liebig-Universität GießenHeinrich-Buff-Ring-1735392GießenGermany
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Ebner F, Mainik P, Greb L. Calix[4]pyrrolato Aluminates: The Effect of Ligand Modification on the Reactivity of Square-Planar Aluminum Anions. Chemistry 2021; 27:5120-5124. [PMID: 33481319 PMCID: PMC8048585 DOI: 10.1002/chem.202005493] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2020] [Indexed: 01/09/2023]
Abstract
Structural constraint represents an attractive tool to modify p-block element properties without the need for unusual oxidation or valence states. The recently reported methyl-calix[4]pyrrolato aluminate established the effect of forcing a tetrahedral aluminum anion into a square-planar coordination mode. However, the generality of this structural motif and any consequence of ligand modification remained open. Herein, a systematic ligand screening was launched, and the class of square-planar aluminum anions was extended by two derivatives that differ in the meso-substitution at the calix[4]pyrrolato ligand. Strikingly, this modification provoked opposing trends in the preference for a Lewis acidic binding mode with σ-donors versus the aluminum-ligand cooperative binding mode with carbonyls. Insights into the origin of these counterintuitive experimental observations were provided by computation and bond analysis. Importantly, this rationale might allow to exploit mode-selective binding for catalytic rate control.
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Affiliation(s)
- Fabian Ebner
- Anorganisch-Chemisches InstitutRuprecht-Karls-Universität HeidelbergIm Neuenheimer Feld 27069120HeidelbergGermany
| | - Philipp Mainik
- Anorganisch-Chemisches InstitutRuprecht-Karls-Universität HeidelbergIm Neuenheimer Feld 27069120HeidelbergGermany
| | - Lutz Greb
- Anorganisch-Chemisches InstitutRuprecht-Karls-Universität HeidelbergIm Neuenheimer Feld 27069120HeidelbergGermany
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