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Scriba GKE. Update on chiral recognition mechanisms in separation science. J Sep Sci 2024; 47:e2400148. [PMID: 38772711 DOI: 10.1002/jssc.202400148] [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: 02/24/2024] [Revised: 04/04/2024] [Accepted: 04/12/2024] [Indexed: 05/23/2024]
Abstract
The stereospecific analysis of chiral molecules is an important issue in many scientific fields. In separation sciences, this is achieved via the formation of transient diastereomeric complexes between a chiral selector and the selectand enantiomers driven by molecular interactions including electrostatic, ion-dipole, dipole-dipole, van der Waals or π-π interactions as well as hydrogen or halogen bonds depending on the nature of selector and selectand. Nuclear magnetic resonance spectroscopy and molecular modeling methods are currently the most frequently applied techniques to understand the selector-selectand interactions at a molecular level and to draw conclusions on the chiral separation mechanism. The present short review summarizes some of the recent achievements for the understanding of the chiral recognition of the most important chiral selectors combining separation techniques with molecular modeling and/or spectroscopic techniques dating between 2020 and early 2024. The selectors include polysaccharide derivatives, cyclodextrins, macrocyclic glycopeptides, proteins, donor-acceptor type selectors, ion-exchangers, crown ethers, and molecular micelles. The application of chiral ionic liquids and chiral deep eutectic solvents, as well as further selectors, are also briefly addressed. A compilation of all published literature on chiral selectors has not been attempted.
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Affiliation(s)
- Gerhard K E Scriba
- Department of Pharmaceutical/Medicinal Chemistry, Friedrich Schiller University, Jena, Germany
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2
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Abstract
Catalysts play a major role in chemical synthesis, and catalysis is considered to be a green and economic process. Catalysis is dominated by covalent interactions between the catalyst and substrate. The design of non-covalent catalysts came into limelight only recently. Hydrogen bonding (HB) catalysts are well established among non-covalent catalysts, including asymmetric HB catalysts. Though halogen bonding (XB) catalysis and its asymmetric version are gaining admiration, non-covalent chalcogen bonding catalysis (ChB) is in the budding stage. This tutorial review will focus on the recently evolved chalcogen bonding catalysis and emphasis will be given to the chalcogen bonding of chiral molecules. Since successful enantioselective chalcogen bonding catalysis is yet to be reported, this review will focus on the basics of non-covalent bonding catalysis, chalcogen bonding catalysis, chiral chalcogenide synthesis, rigidification of transition states by ChB, stabilization of cations by chiral chalcogens, details of unsuccessful asymmetric chalcogen bonding catalysis, enantioseparation of racemic molecules using ChB, and the existence of ChB in chiral biomolecules.
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Affiliation(s)
- Govindasamy Sekar
- Department of Chemistry, IIT Madras, Chennai, Tamilnadu-600 036, India.
| | | | - Jieping Zhu
- Laboratory of Synthesis and Natural Products (LSPN), Institute of Chemical Science and Chemical Engineering, Ecole Polytechnique Fédérale de Lausanne, EPFL-SB-ISIC-LSPN, BCH 5304, 1015 Lausanne, Switzerland.
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Sechi B, Dessì A, Dallocchio R, Tsetskhladze N, Chankvetadze B, Pérez-Baeza M, Cossu S, Jibuti G, Mamane V, Peluso P. Unravelling dispersion forces in liquid-phase enantioseparation. Part I: Impact of ferrocenyl versus phenyl groups. Anal Chim Acta 2023; 1278:341725. [PMID: 37709466 DOI: 10.1016/j.aca.2023.341725] [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: 06/08/2023] [Revised: 08/12/2023] [Accepted: 08/14/2023] [Indexed: 09/16/2023]
Abstract
BACKGROUND Highly ordered chiral secondary structures as well as multiple (tunable) recognition sites are the keys to success of polysaccharide carbamate-based chiral selectors in enantioseparation science. Hydrogen bonds (HBs), dipole-dipole, and π-π interactions are classically considered the most frequent noncovalent interactions underlying enantioselective recognition with these chiral selectors. Very recently, halogen, chalcogen and π-hole bonds were also identified as interactions working in polysaccharide carbamate-based selectors to promote enantiomer distinction. On the contrary, the function of dispersion interactions in this field was not explored so far. RESULTS The enantioseparation of chiral ferrocenes featuring chiral axis or chiral plane as stereogenic elements was performed by comparing five polysaccharide carbamate-based chiral columns, with the aim to identify enantioseparation outcomes that could be reasonably determined by dispersion forces, making available a reliable experimental data set for future theoretical studies to confirm the heuristic hypothesis. The effects of mobile phase polarity and temperature on the enantioseparation were considered, and potential recognition sites on analytes and selectors were evaluated by electrostatic potential (V) analysis and molecular dynamics (MD). In this first part, the enantioseparation of 3,3'-dibromo-5,5'-bis-ferrocenylethynyl-4,4'-bipyridine bearing two ferrocenylethynyl units linked to an axially chiral core was performed and compared to that of the analyte featuring the same structural motif with two phenyl groups in place of the ferrocenyl moieties. The results of this study showed the superiority of the ferrocenyl compared to the phenyl group, as a structural element favouring enantiodifferentiation. SIGNIFICANCE AND NOVELTY Even if dispersion (London) forces have been envisaged acting in liquid-phase enantioseparations, focused studies to explore possible contributions of dispersion forces with polysaccharide carbamate-based selectors are practically missing. This study allowed us to collect experimental information that support the involvement of dispersion forces as contributors to liquid-phase enantioseparation, paving the way to a new picture in this field.
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Affiliation(s)
- Barbara Sechi
- Istituto di Chimica Biomolecolare ICB-CNR, Sede Secondaria di Sassari, Traversa La Crucca 3, Regione Baldinca, Li Punti, 07100, Sassari, Italy
| | - Alessandro Dessì
- Istituto di Chimica Biomolecolare ICB-CNR, Sede Secondaria di Sassari, Traversa La Crucca 3, Regione Baldinca, Li Punti, 07100, Sassari, Italy
| | - Roberto Dallocchio
- Istituto di Chimica Biomolecolare ICB-CNR, Sede Secondaria di Sassari, Traversa La Crucca 3, Regione Baldinca, Li Punti, 07100, Sassari, Italy
| | - Nutsa Tsetskhladze
- Institute of Physical and Analytical Chemistry, School of Exact and Natural Sciences, Tbilisi State University, Chavchavadze Ave 3, 0179, Tbilisi, Georgia
| | - Bezhan Chankvetadze
- Institute of Physical and Analytical Chemistry, School of Exact and Natural Sciences, Tbilisi State University, Chavchavadze Ave 3, 0179, Tbilisi, Georgia
| | - Mireia Pérez-Baeza
- Departamento de Química Analítica, Universitat de València, Burjassot, València, Spain
| | - Sergio Cossu
- Dipartimento di Scienze Molecolari e Nanosistemi DSMN, Università Ca' Foscari Venezia, Via Torino 155, I-30172, Mestre Venezia, Italy
| | - Giorgi Jibuti
- Institute of Physical and Analytical Chemistry, School of Exact and Natural Sciences, Tbilisi State University, Chavchavadze Ave 3, 0179, Tbilisi, Georgia
| | - Victor Mamane
- Institut de Chimie de Strasbourg, UMR, CNRS 7177, Equipe LASYROC, 1 Rue Blaise Pascal, 67008, Strasbourg Cedex, France.
| | - Paola Peluso
- Istituto di Chimica Biomolecolare ICB-CNR, Sede Secondaria di Sassari, Traversa La Crucca 3, Regione Baldinca, Li Punti, 07100, Sassari, Italy.
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Scheiner S. Competition Between the Two σ-Holes in the Formation of a Chalcogen Bond. Chemphyschem 2023; 24:e202200936. [PMID: 36744997 DOI: 10.1002/cphc.202200936] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2022] [Revised: 02/01/2023] [Accepted: 02/06/2023] [Indexed: 02/07/2023]
Abstract
A chalcogen atom Y contains two separate σ-holes when in a R1 YR2 molecular bonding pattern. Quantum chemical calculations consider competition between these two σ-holes to engage in a chalcogen bond (ChB) with a NH3 base. R groups considered include F, Br, I, and tert-butyl (tBu). Also examined is the situation where the Y lies within a chalcogenazole ring, where its neighbors are C and N. Both electron-withdrawing substituents R1 and R2 act cooperatively to deepen the two σ-holes, but the deeper of the two holes consistently lies opposite to the more electron-withdrawing group, and is also favored to form a stronger ChB. The formation of two simultaneous ChBs in a triad requires the Y atom to act as double electron acceptor, and so anti-cooperativity weakens each bond relative to the simple dyad. This effect is such that some of the shallower σ-holes are unable to form a ChB at all when a base occupies the other site.
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Affiliation(s)
- Steve Scheiner
- Department of Chemistry and Biochemistry, Utah State University, 84322-0300, Logan, Utah, USA
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Wang X, Pavlović RZ, Finnegan TJ, Karmakar P, Moore CE, Badjić JD. Rapid Access to Chiral and Tripodal Cavitands from β-Pinene. Chemistry 2022; 28:e202202416. [PMID: 36168151 PMCID: PMC9797447 DOI: 10.1002/chem.202202416] [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: 08/03/2022] [Indexed: 12/31/2022]
Abstract
We report Pd-catalyzed cyclotrimerization of (+)-α-bromoenone, obtained from monoterpene β-pinene, into an enantiopure cyclotrimer. This C3 symmetric compound has three bicyclo[3.1.1]heptane rings fused to its central benzene with each ring carrying a carbonyl group. The cyclotrimer undergoes diastereoselective threefold alkynylation with the lithium salts of five terminal alkynes (41-63 %, de=4-83 %). The addition enabled a rapid synthesis of a small library of novel chiral cavitands that, in shape, resemble a tripod stand. These molecular tripods include a tris-bicycloannelated benzene head attached to three alkyne legs twisted in one direction to form a nonpolar cavity with polar groups as feet. Tripods with methylpyridinium and methylisoquinolinium legs, respectively, form inclusion complexes with anti-inflammatory and chiral drugs (R)/(S)-ibuprofen and (R)/(S)-naproxen. The mode of binding shows drug molecules docked in the cavity of the host through ion-ion, cation-π, and C-H-π contacts that, in addition of desolvation, give rise to complexes having millimolar to micromolar stability in water. Our findings open the door to creating a myriad of enantiopure tripods with tunable functions that, in the future, might give novel chemosensors, catalysts or sequestering agents.
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Affiliation(s)
- Xiuze Wang
- Department of Chemistry and Biochemistry, The Ohio State University, 100 West 18 Avenue, 43210 Columbus, Ohio (USA)
| | - Radoslav Z. Pavlović
- Department of Chemistry and Biochemistry, The Ohio State University, 100 West 18 Avenue, 43210 Columbus, Ohio (USA)
| | - Tyler J. Finnegan
- Department of Chemistry and Biochemistry, The Ohio State University, 100 West 18 Avenue, 43210 Columbus, Ohio (USA)
| | - Pratik Karmakar
- Department of Chemistry and Biochemistry, The Ohio State University, 100 West 18 Avenue, 43210 Columbus, Ohio (USA),Department of Chemistry, King Mongkut’s University of Technology Thonburi (KMUTT), 126 Pracha Uthit Rd., Bang Mod, Thung Khru, Bangkok 10140 (Thailand)
| | - Curtis E. Moore
- Department of Chemistry and Biochemistry, The Ohio State University, 100 West 18 Avenue, 43210 Columbus, Ohio (USA)
| | - Jovica D. Badjić
- Department of Chemistry and Biochemistry, The Ohio State University, 100 West 18 Avenue, 43210 Columbus, Ohio (USA)
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Scheiner S. Adjusting the balance between hydrogen and chalcogen bonds. Phys Chem Chem Phys 2022; 24:28944-28955. [PMID: 36416473 DOI: 10.1039/d2cp04591e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
A complex is assembled which pairs a carboxyl group of X1COOH with a 1,2,5-chalcogenadiazole ring containing substituents on its C atoms. The OH of the carboxyl group donates a proton to a N atom of the ring to form a OH⋯N H-bond (HB), while its carbonyl O engages in a Y⋯O chalcogen bond (ChB) with the ring in which Y = S, Se, Te. The ChB is strengthened by enlarging the size of the Y atom from S to Se to Te. Placement of an electron-withdrawing group (EWG) X1 on the acid strengthens the HB while weakening the ChB; the reverse occurs when EWGs are placed on the ring. By selection of the proper substituents on the two units, it is possible to achieve a near perfect balance between the strengths of these two bonds. These bond strengths are also reflected in the NMR spectroscopic properties of the chemical shielding of the various atoms and the coupling between the nuclei directly involved in each bond.
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Affiliation(s)
- Steve Scheiner
- Department of Chemistry and Biochemistry, Utah State University, Logan, Utah 84322-0300, USA.
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Peluso P, Chankvetadze B. Recognition in the Domain of Molecular Chirality: From Noncovalent Interactions to Separation of Enantiomers. Chem Rev 2022; 122:13235-13400. [PMID: 35917234 DOI: 10.1021/acs.chemrev.1c00846] [Citation(s) in RCA: 53] [Impact Index Per Article: 26.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
It is not a coincidence that both chirality and noncovalent interactions are ubiquitous in nature and synthetic molecular systems. Noncovalent interactivity between chiral molecules underlies enantioselective recognition as a fundamental phenomenon regulating life and human activities. Thus, noncovalent interactions represent the narrative thread of a fascinating story which goes across several disciplines of medical, chemical, physical, biological, and other natural sciences. This review has been conceived with the awareness that a modern attitude toward molecular chirality and its consequences needs to be founded on multidisciplinary approaches to disclose the molecular basis of essential enantioselective phenomena in the domain of chemical, physical, and life sciences. With the primary aim of discussing this topic in an integrated way, a comprehensive pool of rational and systematic multidisciplinary information is provided, which concerns the fundamentals of chirality, a description of noncovalent interactions, and their implications in enantioselective processes occurring in different contexts. A specific focus is devoted to enantioselection in chromatography and electromigration techniques because of their unique feature as "multistep" processes. A second motivation for writing this review is to make a clear statement about the state of the art, the tools we have at our disposal, and what is still missing to fully understand the mechanisms underlying enantioselective recognition.
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Affiliation(s)
- Paola Peluso
- Istituto di Chimica Biomolecolare ICB, CNR, Sede secondaria di Sassari, Traversa La Crucca 3, Regione Baldinca, Li Punti, I-07100 Sassari, Italy
| | - Bezhan Chankvetadze
- Institute of Physical and Analytical Chemistry, School of Exact and Natural Sciences, Tbilisi State University, Chavchavadze Avenue 3, 0179 Tbilisi, Georgia
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Peluso P, Mamane V. Stereoselective Processes Based on σ-Hole Interactions. Molecules 2022; 27:molecules27144625. [PMID: 35889497 PMCID: PMC9323542 DOI: 10.3390/molecules27144625] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2022] [Revised: 07/13/2022] [Accepted: 07/15/2022] [Indexed: 02/01/2023] Open
Abstract
The σ-hole interaction represents a noncovalent interaction between atoms with σ-hole(s) on their surface (such as halogens and chalcogens) and negative sites. Over the last decade, significant developments have emerged in applications where the σ-hole interaction was demonstrated to play a key role in the control over chirality. The aim of this review is to give a comprehensive overview of the current advancements in the use of σ-hole interactions in stereoselective processes, such as formation of chiral supramolecular assemblies, separation of enantiomers, enantioselective complexation and asymmetric catalysis.
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Affiliation(s)
- Paola Peluso
- Istituto di Chimica Biomolecolare ICB, CNR, Sede Secondaria di Sassari, Traversa La Crucca 3, Regione Baldinca, Li Punti, 07100 Sassari, Italy
- Correspondence: (P.P.); (V.M.)
| | - Victor Mamane
- Institut de Chimie de Strasbourg, UMR CNRS 7177, Equipe LASYROC, 1 Rue Blaise Pascal, 67008 Strasbourg, France
- Correspondence: (P.P.); (V.M.)
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Unravelling functions of halogen substituents in the enantioseparation of halogenated planar chiral ferrocenes on polysaccharide-based chiral stationary phases: experimental and electrostatic potential analyses. J Chromatogr A 2022; 1673:463097. [DOI: 10.1016/j.chroma.2022.463097] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2022] [Revised: 04/27/2022] [Accepted: 04/28/2022] [Indexed: 12/31/2022]
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Dessì A, Sechi B, Dallocchio R, Chankvetadze B, Pérez‐Baeza M, Cossu S, Mamane V, Pale P, Peluso P. Comparative enantioseparation of planar chiral ferrocenes on polysaccharide‐based chiral stationary phases. Chirality 2022; 34:609-619. [DOI: 10.1002/chir.23417] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2021] [Revised: 01/03/2022] [Accepted: 01/05/2022] [Indexed: 12/19/2022]
Affiliation(s)
| | - Barbara Sechi
- Istituto di Chimica Biomolecolare ICB CNR Sassari Italy
| | | | - Bezhan Chankvetadze
- Institute of Physical and Analytical Chemistry, School of Exact and Natural Sciences Tbilisi State University Tbilisi Georgia
| | - Mireia Pérez‐Baeza
- Departamento de Química Analítica Universitat de València València Spain
| | - Sergio Cossu
- Dipartimento di Scienze Molecolari e Nanosistemi DSMN Università Ca' Foscari Venezia Venice Italy
| | - Victor Mamane
- Institut de Chimie de Strasbourg, UMR CNRS 7177, Equipe LASYROC Strasbourg Cedex France
| | - Patrick Pale
- Institut de Chimie de Strasbourg, UMR CNRS 7177, Equipe LASYROC Strasbourg Cedex France
| | - Paola Peluso
- Istituto di Chimica Biomolecolare ICB CNR Sassari Italy
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Rosetti A, Preda G, Villani C, Pierini M, Pasini D, Cirilli R. Triptycene derivatives as chiral probes for studying the molecular enantiorecognition on sub-2-μm particle cellulose tris(3,5-dimethylphenylcarbamate) chiral stationary phase. Chirality 2021; 33:883-890. [PMID: 34571576 DOI: 10.1002/chir.23358] [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: 06/25/2021] [Revised: 08/04/2021] [Accepted: 08/26/2021] [Indexed: 11/09/2022]
Abstract
Two chiral triptycene derivatives were analyzed on the Chiralpak IB-U column packed with cellulose tris(3,5-dimethylphenylcarbamate)-based sub-2-μm diameter particles. Under normal-phase conditions, sub-minute baseline enantioseparations were obtained. Differences in structural elements and chromatographic behavior of the investigated compounds were evaluated to identify the interactions that drive the chiral discrimination process. From the evaluation of the experimental chromatographic data, it was found that hydrogen bond formation is essential for the separation of enantiomers.
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Affiliation(s)
- Alessia Rosetti
- Department of Chemistry and Drug Technology, Sapienza University of Rome, Rome, Italy
| | - Giovanni Preda
- Department of Chemistry and INSTM Research Unit, University of Pavia, Pavia, Italy
| | - Claudio Villani
- Department of Chemistry and Drug Technology, Sapienza University of Rome, Rome, Italy
| | - Marco Pierini
- Department of Chemistry and Drug Technology, Sapienza University of Rome, Rome, Italy
| | - Dario Pasini
- Department of Chemistry and INSTM Research Unit, University of Pavia, Pavia, Italy
| | - Roberto Cirilli
- National Center for the Control and Evaluation of Drugs, Istituto Superiore di Sanità, Rome, Italy
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Scheiner S. Dissection of the Origin of π-Holes and the Noncovalent Bonds in Which They Engage. J Phys Chem A 2021; 125:6514-6528. [PMID: 34310147 DOI: 10.1021/acs.jpca.1c05431] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Accompanying the rapidly growing list of σ-hole bonds has come the acknowledgment of parallel sorts of noncovalent bonds which owe their stability in large part to a deficiency of electron density in the area above the molecular plane, known as a π-hole. The origins of these π-holes are probed for a wide series of molecules, comprising halogen, chalcogen, pnicogen, tetrel, aerogen, and spodium bonds. Much like in the case of their σ-hole counterparts, formation of the internal covalent π-bond in the Lewis acid molecule pulls density toward the bond midpoint and away from its extremities. This depletion of density above the central atom is amplified by an electron-withdrawing substituent. At the same time, the amplitude of the π*-orbital is enhanced in the region of the density-depleted π-hole, facilitating a better overlap with the nucleophile's lone pair orbital and a stabilizing n → π* charge transfer. The presence of lone pairs on the central atom acts to attenuate the π-hole and shift its position somewhat, resulting in an overall weakening of the π-hole bond. There is a tendency for π-hole bonds to include a higher fraction of induction energy than σ-bonds with proportionately smaller electrostatic and dispersion components, but this distinction is less a product of the σ- or π-character and more a function of the overall bond strength.
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Affiliation(s)
- Steve Scheiner
- Department of Chemistry and Biochemistry, Utah State University, Logan, Utah 84322-0300, United States
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