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Timoshkin AY. The Field of Main Group Lewis Acids and Lewis Superacids: Important Basics and Recent Developments. Chemistry 2024; 30:e202302457. [PMID: 37752859 DOI: 10.1002/chem.202302457] [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: 07/30/2023] [Revised: 09/25/2023] [Accepted: 09/27/2023] [Indexed: 09/28/2023]
Abstract
New developments in the field of Lewis acidity are highlighted, with the focus of novel Lewis acids and Lewis superacids of group 2, 13, 14, and 15 elements. Several important basics, illustrated by modern examples (classification of Donor-Acceptor (DA) complexes, amphoteric nature of any compound in terms of DA interactions, reorganization energies of main group Lewis acids and the role of the energies of frontier orbitals) are presented and discussed. It is emphasized that the Lewis acidity phenomena are general and play vital role in different areas of chemistry: from weak "atomophilic" interactions to the complexes of Lewis superacids.
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Affiliation(s)
- Alexey Y Timoshkin
- Institute of Chemistry, St. Petersburg State University, 199034, Universitetskaya emb. 7/9, St. Petersburg, Russia
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Pomogaeva AV, Timoshkin AY. Hydrogen Activation by Frustrated and Not So Frustrated Lewis Pairs Based on Pyramidal Lewis Acid 9-Boratriptycene: A Computational Study. ACS OMEGA 2022; 7:48493-48505. [PMID: 36591180 PMCID: PMC9798527 DOI: 10.1021/acsomega.2c06836] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/23/2022] [Accepted: 12/06/2022] [Indexed: 06/17/2023]
Abstract
Structural features and reactivity of frustrated Lewis pairs (FLPs) formed by pyramidal group 13 Lewis acids based on 9-bora and 9-alatriptycene and bulky phosphines P t Bu3, PPh3, and PCy3 are considered at the M06-2X/def2-TZVP level of theory. Classic FLP is formed only in the B(C6Me4)3CH/P t Bu3 system, while both FLP and donor-acceptor (DA) complex are observed in the B(C6F4)3CF/P t Bu3 system. Formation of DA complexes was observed in other systems; the B(C6H4)3CH·P t Bu3 complex features an elongated DA bond and can be considered a "latent" FLP. Transition states and reaction pathways for molecular hydrogen activation have been obtained. Processes of heterolytic hydrogen splitting are energetically more favored in solution compared to the gas phase, while activation energies in the gas phase and in solution are close. The alternative processes of hydrogenation of B-C or Al-C bonds in the source pyramidal Lewis acids in the absence of a Lewis base are exergonic but have larger activation energies than those for heterolytic hydrogen splitting. The tuning of Lewis acidity of 9-boratriptycene by changing the substituents allows one to control its reactivity with respect to hydrogen activation. Interestingly, the most promising system from the practical point of view is the DA complex B(C6H4)3CH·P t Bu3, which is predicted to provide both low activation energy and thermodynamic reversibility of the heterolytic hydrogen splitting process. It appears that such "not so frustrated" or "latent" FLPs are the best candidates for reversible heterolytic hydrogen splitting.
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Mahaut D, Berionni G, Champagne B. 9-Phosphatriptycene Derivatives: From Their Weak Basicity to Their Application in Frustrated Lewis Pair Chemistry. J Phys Chem A 2022; 126:2794-2801. [PMID: 35507420 DOI: 10.1021/acs.jpca.2c01339] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
The accurate prediction of the basicity of tertiary phosphines in acetonitrile and water is reported by the linear correlation between computed ΔpKa's obtained by density functional theory (DFT) and experimental values extracted from the literature. This method is applied to the prediction of pKa values of 9-phosphatriptycene derivatives and showed that they are weaker Brønsted bases than their triphenylphosphine analogues. This lower reactivity is attributed to their high pyramidalization that increases their lone pair 3s character, stabilizing its energy level. Their potential application in frustrated Lewis pair chemistry is then considered by investigating the hydrogenation of 1,1-diphenylethylene by the tris(pentafluorophenyl)borane/1-chloro-9-phosphatriptycene frustrated Lewis pair.
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Affiliation(s)
- Damien Mahaut
- Department of Chemistry, NISM (Namur Institute of Structured Matter), University of Namur, Rue de Bruxelles 61, Namur B-5000, Belgium
| | - Guillaume Berionni
- Department of Chemistry, NISM (Namur Institute of Structured Matter), University of Namur, Rue de Bruxelles 61, Namur B-5000, Belgium
| | - Benoît Champagne
- Department of Chemistry, NISM (Namur Institute of Structured Matter), University of Namur, Rue de Bruxelles 61, Namur B-5000, Belgium
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Kistner L, Kowatsch D, Marz A, Kaifer E, Himmel H. Directed Synthesis and Chemistry of Unsymmetric Dicationic Diboranes and Their Use in Frustrated Lewis Pair-like Chemistry. Chemistry 2022; 28:e202104016. [PMID: 35061309 PMCID: PMC9305129 DOI: 10.1002/chem.202104016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2021] [Indexed: 11/15/2022]
Abstract
The chemistry of dicationic diboranes with two BII atoms that are engaged in direct B-B bonding is by enlarge unexplored, although these molecules have intriguing properties due to their combined Lewis acidic and electron-donor properties. Unsymmetric dicationic diboranes are extremely rare, but especially attractive due to their polarized B-B bond. In this work we report the directed synthesis of several stable unsymmetric dicationic diboranes by reaction between the electron-rich ditriflato-diborane B2 (hpp)2 (OTf)2 (hpp=1,3,4,6,7,8-hexahydro-2H-pyrimido[1,2-α]pyrimidinate) and phosphino-pyridines, establishing B-N and B-P bonds with the diborane concomitant with triflate elimination. In the case of 2-((ditertbutylphosphino)methyl)pyridine, the B-N bond is formed instantly, but the B-P bond formation requires (due to steric constraints) several days at ambient conditions for completion, creating an intermediate that could be used for frustrated Lewis pair (FLP)-like chemistry. Here we test its reaction with an aldehyde, and propose a new type of FLP-like chemistry.
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Affiliation(s)
- Lucas Kistner
- Anorganisch-Chemisches InstitutRuprecht-Karls Universität HeidelbergIm Neuenheimer Feld 27069120HeidelbergGermany
| | - Dario Kowatsch
- Anorganisch-Chemisches InstitutRuprecht-Karls Universität HeidelbergIm Neuenheimer Feld 27069120HeidelbergGermany
| | - Andreas Marz
- Anorganisch-Chemisches InstitutRuprecht-Karls Universität HeidelbergIm Neuenheimer Feld 27069120HeidelbergGermany
| | - Elisabeth Kaifer
- Anorganisch-Chemisches InstitutRuprecht-Karls Universität HeidelbergIm Neuenheimer Feld 27069120HeidelbergGermany
| | - Hans‐Jörg Himmel
- Anorganisch-Chemisches InstitutRuprecht-Karls Universität HeidelbergIm Neuenheimer Feld 27069120HeidelbergGermany
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Modulating acid-base properties of ZIF-8 by thermal-induced structure evolution. J Catal 2022. [DOI: 10.1016/j.jcat.2021.12.033] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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Henkelmann M, Omlor A, Bolte M, Schünemann V, Lerner HW, Noga J, Hrobárik P, Wagner M. A free boratriptycene-type Lewis superacid. Chem Sci 2022; 13:1608-1617. [PMID: 35282635 PMCID: PMC8826627 DOI: 10.1039/d1sc06404e] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2021] [Accepted: 12/05/2021] [Indexed: 11/21/2022] Open
Abstract
An exceptionally strong ferrocene-containing, cationic boratriptycene-type Lewis acid is stabilized by a weak Fe⋯B through-space interaction.
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Affiliation(s)
- Marcel Henkelmann
- Institute of Inorganic Chemistry, Goethe University Frankfurt, Max-von-Laue-Straße 7, 60438 Frankfurt am Main, Germany
| | - Andreas Omlor
- Physics Department, University Kaiserslautern, Erwin-Schrödinger-Straße 56, 67663 Kaiserslautern, Germany
| | - Michael Bolte
- Institute of Inorganic Chemistry, Goethe University Frankfurt, Max-von-Laue-Straße 7, 60438 Frankfurt am Main, Germany
| | - Volker Schünemann
- Physics Department, University Kaiserslautern, Erwin-Schrödinger-Straße 56, 67663 Kaiserslautern, Germany
| | - Hans-Wolfram Lerner
- Institute of Inorganic Chemistry, Goethe University Frankfurt, Max-von-Laue-Straße 7, 60438 Frankfurt am Main, Germany
| | - Jozef Noga
- Department of Inorganic Chemistry, Faculty of Natural Sciences, Comenius University, Ilkovicova 6, 84215 Bratislava, Slovakia
| | - Peter Hrobárik
- Department of Inorganic Chemistry, Faculty of Natural Sciences, Comenius University, Ilkovicova 6, 84215 Bratislava, Slovakia
| | - Matthias Wagner
- Institute of Inorganic Chemistry, Goethe University Frankfurt, Max-von-Laue-Straße 7, 60438 Frankfurt am Main, Germany
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Belen’kii LI, Gazieva GA, Evdokimenkova YB, Soboleva NO. The literature of heterocyclic chemistry, Part XX, 2020. ADVANCES IN HETEROCYCLIC CHEMISTRY 2022. [DOI: 10.1016/bs.aihch.2022.10.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/05/2022]
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Mahaut D, Chardon A, Mineur L, Berionni G, Champagne B. Rational Development of a Metal-Free Bifunctional System for the C-H Activation of Methane: A Density Functional Theory Investigation. Chemphyschem 2021; 22:1958-1966. [PMID: 34309144 DOI: 10.1002/cphc.202100527] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2021] [Indexed: 11/10/2022]
Abstract
The activation or heterolytic splitting of methane, a challenging substrate usually restricted to transition metals, has so far proven elusive in experimental frustrated Lewis pair (FLP) chemistry. In this article, we demonstrate, using density functional theory (DFT), that 1-aza-9-boratriptycene is a conceptually simple intramolecular FLP for the activation of methane. Systematic comparison with other FLP systems allows to gain insight into their reactivity with methane. The thermodynamics and kinetics of methane activation are interpreted by referring to the analysis of the natural charges and by employing the distortion-interaction/activation strain (DIAS) model. These showed that the nature of the Lewis base influences the selectivity over the reaction pathway, with N Lewis bases favoring the deprotonation mechanism and P bases the hydride abstraction one. The lower barrier of activation for 1-aza-9-boratriptycene and the higher products stability are due to a better interaction energy than its counterparts, itself due to electrostatic interactions with the methane moiety, favorable orbital overlaps allowed by the side-attack, and space proximity between the B and N atoms.
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Affiliation(s)
- Damien Mahaut
- Department of Chemistry, Namur Institute of Structured Matter, University of Namur, Rue de Bruxelles 61, B-5000, Namur, Belgium
| | - Aurélien Chardon
- Department of Chemistry, Namur Institute of Structured Matter, University of Namur, Rue de Bruxelles 61, B-5000, Namur, Belgium
| | - Loïc Mineur
- Department of Chemistry, Namur Institute of Structured Matter, University of Namur, Rue de Bruxelles 61, B-5000, Namur, Belgium
| | - Guillaume Berionni
- Department of Chemistry, Namur Institute of Structured Matter, University of Namur, Rue de Bruxelles 61, B-5000, Namur, Belgium
| | - Benoît Champagne
- Department of Chemistry, Namur Institute of Structured Matter, University of Namur, Rue de Bruxelles 61, B-5000, Namur, Belgium
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