1
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Goldup SM. The End of the Beginning of Mechanical Stereochemistry. Acc Chem Res 2024; 57:1696-1708. [PMID: 38830116 PMCID: PMC11191403 DOI: 10.1021/acs.accounts.4c00195] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2024] [Revised: 04/29/2024] [Accepted: 05/01/2024] [Indexed: 06/05/2024]
Abstract
ConspectusStereochemistry has played a key role in the development of synthetic chemistry for the simple reason that the function and properties of most molecules, from medicine to materials science, depend on their shape and thus the stereoisomer used. However, despite the potential for rotaxanes and catenanes to display unusual forms of stereochemistry being identified as early as 1961, this aspect of the mechanical bond remained underexplored and underexploited; until 2014 it was only possible to access chiral rotaxanes and catenanes whose stereoisomerism is solely attributable to the mechanical bond using chiral stationary phase high performance liquid chromatography, which limited their production on scale and thus inhibited the investigation of their properties and applications. Furthermore, the stereogenic units of such molecules and analogues were often poorly described, which made it hard to fully articulate both what had been achieved in the field and what problems were left to solve. Relatively recently, methods to access rotaxanes and catenanes that display mechanical stereochemistry selectively have been developed, making these intriguing structures available for study in a range of prototypical applications including catalysis, sensing, and as chiral luminophores.In this Account, we briefly discuss the history of mechanical stereochemistry, beginning in 1961 when the potential for mechanical stereoisomerism was first identified, before defining how mechanical stereochemistry arises from a structural point of view. Building on this, using simple stereochemical arguments, we confirm that the complete set of unique stereogenic units of two-component rotaxanes and catenanes have finally been identified and categorized unambiguously, with the last being identified only in 2024. After pausing to discuss some of the stereochemical curiosities that arise when molecules contain both covalent and mechanical stereogenic units, and the potential for stereoisomerism to arise due to co-conformational movement, we use our stereochemical framework to summarize our efforts to develop conceptually general approaches to [2]catenanes and [2]rotaxanes containing all of the possible mechanical stereogenic units. In particular, we highlight how the nature of a mechanical stereogenic unit affects the available strategies for their stereoselective synthesis. We finish by highlighting recent prototypical chemical applications of interlocked molecules that rely on their mechanical stereochemistry, before discussing future directions and challenges.Taken together, we propose that the transition of such molecules from being hard to make and poorly described, to being available in high stereopurity using clearly articulated methodological and stereochemical concepts suggests that the field is finally maturing. Thus, we are now coming to the end of the beginning of mechanical stereochemistry. The stage is now set for such molecules to play a functional role in a range of areas, indeed in any chemical or physical application where control over molecular shape is required.
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Affiliation(s)
- Stephen M. Goldup
- School of Chemistry, University
of Birmingham, Birmingham B15 2TT, U.K.
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2
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Gallagher P, Savoini A, Saady A, Maynard JRJ, Butler PWV, Tizzard GJ, Goldup SM. Facial Selectivity in Mechanical Bond Formation: Axially Chiral Enantiomers and Geometric Isomers from a Simple Prochiral Macrocycle. J Am Chem Soc 2024; 146:9134-9141. [PMID: 38507717 PMCID: PMC10996000 DOI: 10.1021/jacs.3c14329] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2023] [Revised: 02/12/2024] [Accepted: 02/14/2024] [Indexed: 03/22/2024]
Abstract
In 1971, Schill recognized that a prochiral macrocycle encircling an oriented axle led to geometric isomerism in rotaxanes. More recently, we identified an overlooked chiral stereogenic unit in rotaxanes that arises when a prochiral macrocycle encircles a prochiral axle. Here, we show that both stereogenic units can be accessed using equivalent strategies, with a single weak stereodifferentiating interaction sufficient for moderate to excellent stereoselectivity. Using this understanding, we demonstrated the first direct enantioselective (70% ee) synthesis of a mechanically axially chiral rotaxane.
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Affiliation(s)
- Peter
R. Gallagher
- Chemistry, University of Southampton, University Road, Southampton, SO17 1BJ, U.K.
- School
of Chemistry, University of Birmingham, Edgbaston, Birmingham B15 2TT, U.K.
| | - Andrea Savoini
- Chemistry, University of Southampton, University Road, Southampton, SO17 1BJ, U.K.
- School
of Chemistry, University of Birmingham, Edgbaston, Birmingham B15 2TT, U.K.
| | - Abed Saady
- Chemistry, University of Southampton, University Road, Southampton, SO17 1BJ, U.K.
- School
of Chemistry, University of Birmingham, Edgbaston, Birmingham B15 2TT, U.K.
| | - John R. J. Maynard
- Chemistry, University of Southampton, University Road, Southampton, SO17 1BJ, U.K.
| | - Patrick W. V. Butler
- Chemistry, University of Southampton, University Road, Southampton, SO17 1BJ, U.K.
| | - Graham J. Tizzard
- Chemistry, University of Southampton, University Road, Southampton, SO17 1BJ, U.K.
| | - Stephen M. Goldup
- Chemistry, University of Southampton, University Road, Southampton, SO17 1BJ, U.K.
- School
of Chemistry, University of Birmingham, Edgbaston, Birmingham B15 2TT, U.K.
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3
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Savoini A, Gallagher PR, Saady A, Goldup SM. The Final Stereogenic Unit of [2]Rotaxanes: Type 2 Geometric Isomers. J Am Chem Soc 2024; 146:8472-8479. [PMID: 38499387 PMCID: PMC10979452 DOI: 10.1021/jacs.3c14594] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2023] [Revised: 02/12/2024] [Accepted: 02/14/2024] [Indexed: 03/20/2024]
Abstract
Mechanical stereochemistry arises when the interlocking of stereochemically trivial covalent subcomponents results in a stereochemically complex object. Although this general concept was identified in 1961, the stereochemical description of these molecules is still under development to the extent that new forms of mechanical stereochemistry are still being identified. Here, we present a simple analysis of rotaxane and catenane stereochemistry that allowed us to identify the final missing simple mechanical stereogenic unit, an overlooked form of rotaxane geometric isomerism, and demonstrate its stereoselective synthesis.
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Affiliation(s)
- Andrea Savoini
- School
of Chemistry, University of Southampton, University Road, Southampton SO17 1BJ, U.K.
- School
of Chemistry, University of Birmingham, Edgbaston, Birmingham B15 2TT, U.K.
| | - Peter R. Gallagher
- School
of Chemistry, University of Southampton, University Road, Southampton SO17 1BJ, U.K.
- School
of Chemistry, University of Birmingham, Edgbaston, Birmingham B15 2TT, U.K.
| | - Abed Saady
- School
of Chemistry, University of Southampton, University Road, Southampton SO17 1BJ, U.K.
- School
of Chemistry, University of Birmingham, Edgbaston, Birmingham B15 2TT, U.K.
| | - Stephen M. Goldup
- School
of Chemistry, University of Southampton, University Road, Southampton SO17 1BJ, U.K.
- School
of Chemistry, University of Birmingham, Edgbaston, Birmingham B15 2TT, U.K.
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4
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Bazzoni M, Andreoni L, Silvi S, Credi A, Cera G, Secchi A, Arduini A. Selective access to constitutionally identical, orientationally isomeric calix[6]arene-based [3]rotaxanes by an active template approach. Chem Sci 2021; 12:6419-6428. [PMID: 34084442 PMCID: PMC8115267 DOI: 10.1039/d1sc00279a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
Tris(phenylureido)calix[6]arene is endowed with unique properties that make it a valuable macrocyclic component for the synthesis of mechanically interlocked molecules. Its three-dimensional and intrinsically nonsymmetric structure is kinetically selective toward two processes: (i) in apolar media, the threading of bipyridinium based axle-like components takes place exclusively from the upper rim; (ii) SN2 alkylation reactions of a pyridylpyridinium precursor engulfed in the cavity occur selectively at pyridylpyridinium nitrogen atom located at the macrocycle upper rim (active template synthesis). Here we exploit such properties to prepare two series of [3]rotaxanes, each consisting of three sequence isomers that arise from the threading of two identical but nonsymmetric wheels on a symmetric thread differing only for the reciprocal orientation of the macrocycles. The features of the calix[6]arene and the active template synthetic approach, together with a careful selection of the precursors, enabled us to selectively synthesise the [3]rotaxane sequence isomers of each series with fast kinetics and high yields. Expedient access to a series of spatially controlled oriented [3]rotaxane isomers via a metal-free active template approach.![]()
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Affiliation(s)
- Margherita Bazzoni
- Dipartimento di Scienze Chimiche, della Vita e della Sostenibilità Ambientale, Università di Parma Parco Area delle Scienze 17/A I-43124 Parma Italy
| | - Leonardo Andreoni
- Dipartimento di Chimica "G. Ciamician", Università di Bologna Via Selmi 2 I-40126 Bologna Italy
| | - Serena Silvi
- Dipartimento di Chimica "G. Ciamician", Università di Bologna Via Selmi 2 I-40126 Bologna Italy
| | - Alberto Credi
- Istituto per la Sintesi Organica e la Fotoreattività, Consiglio Nazionale delle Ricerche Via Gobetti 101 I-40129 Bologna Italy.,Dipartimento di Chimica Industriale "Toso Montanari", Università di Bologna Viale del Risorgimento 4 I-40136 Bologna Italy
| | - Gianpiero Cera
- Dipartimento di Scienze Chimiche, della Vita e della Sostenibilità Ambientale, Università di Parma Parco Area delle Scienze 17/A I-43124 Parma Italy
| | - Andrea Secchi
- Dipartimento di Scienze Chimiche, della Vita e della Sostenibilità Ambientale, Università di Parma Parco Area delle Scienze 17/A I-43124 Parma Italy
| | - Arturo Arduini
- Dipartimento di Scienze Chimiche, della Vita e della Sostenibilità Ambientale, Università di Parma Parco Area delle Scienze 17/A I-43124 Parma Italy
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5
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Cera G, Arduini A, Secchi A, Credi A, Silvi S. Heteroditopic Calix[6]arene Based Intervowen and Interlocked Molecular Devices. CHEM REC 2021; 21:1161-1181. [PMID: 33656250 DOI: 10.1002/tcr.202100012] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2021] [Revised: 02/17/2021] [Indexed: 01/13/2023]
Abstract
Since the dawn of supramolecular chemistry, calixarenes have been employed as platforms onto which functional groups and binding sites can be loaded in a regio- and stereocontrolled manner for the recognition of charged and neutral species. Despite their wider annulus, potentially suitable to bind larger guests, the larger members of the calixarene series have been relatively less employed, mainly because of the synthetic difficulties to control their conformational flexibility and their regioselective functionalization. In this account, we will present the achievements gained during the last two decades on the use of the calix[6]arene as a platform to build-up structures in which the macrocycle acts as a wheel for the synthesis of oriented (pseudo)rotaxanes. We also account on how these calix[6]arene hosts affect the reactivity or spectroscopic properties of their bound guests.
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Affiliation(s)
- Gianpiero Cera
- Dipartimento di Scienze Chimiche, della Vita e della Sostenibilità Ambientale, Università di Parma, Parco Area delle Scienze 17/A, I-43124, Parma, Italy
| | - Arturo Arduini
- Dipartimento di Scienze Chimiche, della Vita e della Sostenibilità Ambientale, Università di Parma, Parco Area delle Scienze 17/A, I-43124, Parma, Italy
| | - Andrea Secchi
- Dipartimento di Scienze Chimiche, della Vita e della Sostenibilità Ambientale, Università di Parma, Parco Area delle Scienze 17/A, I-43124, Parma, Italy
| | - Alberto Credi
- Dipartimento di Chimica Industriale "Toso Montanari", Viale del Risorgimento 4, I-40136, Bologna, Italy.,Istituto per la Sintesi Organica e la Foto reattività, Consiglio Nazionale delle Ricerche, via Gobetti 101, 40129, Bologna, Italy
| | - Serena Silvi
- Dipartimento di Chimica "G. Ciamician", Università di Bologna, Via Selmi 2, I-40126, Bologna, Italy
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6
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Iwamoto T, Miyagawa S, Naito M, Tokunaga Y. Orientation of the α-CD component of [2]rotaxanes affects their specific molecular recognition behaviour. Org Chem Front 2021. [DOI: 10.1039/d0qo01337d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
An α-CD component enhanced the anion recognition ability of the urea moiety and the deprotonation of the phenol moiety in the axle component in orientationally isomeric [2]rotaxanes with the OH groups on the wide rim of the α-CD, respectively.
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Affiliation(s)
- Takuya Iwamoto
- Department of Materials Science and Engineering
- Faculty of Engineering
- University of Fukui
- Bunkyo
- Japan
| | - Shinobu Miyagawa
- Department of Materials Science and Engineering
- Faculty of Engineering
- University of Fukui
- Bunkyo
- Japan
| | - Masaya Naito
- Department of Materials Science and Engineering
- Faculty of Engineering
- University of Fukui
- Bunkyo
- Japan
| | - Yuji Tokunaga
- Department of Materials Science and Engineering
- Faculty of Engineering
- University of Fukui
- Bunkyo
- Japan
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7
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Bazzoni M, Terenziani F, Secchi A, Cera G, Jabin I, De Leener G, Luhmer M, Arduini A. Tuning the Fluorescence Through Reorientation of the Axle in Calix[6]arene-Based Pseudorotaxanes. Chemistry 2020; 26:3022-3025. [PMID: 31944456 DOI: 10.1002/chem.201905500] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2019] [Indexed: 12/31/2022]
Abstract
This work describes a calix[6]arene-based wheel that binds, in non-polar media, a stilbazolium salt to yield a mixture of pseudorotaxane orientational isomers. The isomer's abundance ratio evolves with time and can be reversibly tuned by adjusting the temperature. The spectroscopic properties, and notably the emission spectrum, of the bound guest depend on its orientation inside the non-palindromic wheel, suggesting such a system as a switch with spectroscopic readout.
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Affiliation(s)
- Margherita Bazzoni
- Dipartimento di Scienze Chimiche, della Vita e, della Sostenibilità Ambientale, Università degli Studi di Parma, Parco Area delle Scienze 17/A, 43124, Parma, Italy
| | - Francesca Terenziani
- Dipartimento di Scienze Chimiche, della Vita e, della Sostenibilità Ambientale, Università degli Studi di Parma, Parco Area delle Scienze 17/A, 43124, Parma, Italy
| | - Andrea Secchi
- Dipartimento di Scienze Chimiche, della Vita e, della Sostenibilità Ambientale, Università degli Studi di Parma, Parco Area delle Scienze 17/A, 43124, Parma, Italy
| | - Gianpiero Cera
- Dipartimento di Scienze Chimiche, della Vita e, della Sostenibilità Ambientale, Università degli Studi di Parma, Parco Area delle Scienze 17/A, 43124, Parma, Italy
| | - Ivan Jabin
- Laboratoire de Chimie Organique, Université libre de Bruxelles (ULB), Avenue F.D. Roosevelt 50, CP160/06, 1050, Brussels, Belgium
| | - Gaël De Leener
- Centre d'Instrumentation en REsonance Magnétique (CIREM), Laboratoire de Résonance Magnétique Nucléaire Haute Résolution, Université libre de Bruxelles (ULB), Avenue F.D. Roosevelt 50, CP160/08, 1050, Brussels, Belgium
| | - Michel Luhmer
- Centre d'Instrumentation en REsonance Magnétique (CIREM), Laboratoire de Résonance Magnétique Nucléaire Haute Résolution, Université libre de Bruxelles (ULB), Avenue F.D. Roosevelt 50, CP160/08, 1050, Brussels, Belgium
| | - Arturo Arduini
- Dipartimento di Scienze Chimiche, della Vita e, della Sostenibilità Ambientale, Università degli Studi di Parma, Parco Area delle Scienze 17/A, 43124, Parma, Italy
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8
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Orlandini G, Casimiro L, Bazzoni M, Cogliati B, Credi A, Lucarini M, Silvi S, Arduini A, Secchi A. Synthesis and properties of a redox-switchable calix[6]arene-based molecular lasso. Org Chem Front 2020. [DOI: 10.1039/c9qo01379b] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
A self-complexing lasso-like molecule has been synthesised as the first example of a calix[6]arene-based [1]pseudorotaxane. This artificial molecular lasso can be switched between self-threaded and dethreaded structures by redox stimulation.
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Affiliation(s)
- Guido Orlandini
- Dipartimento di Scienze Chimiche
- della Vita e della Sostenibilità Ambientale
- Università di Parma
- I-43124 Parma
- Italy
| | - Lorenzo Casimiro
- Dipartimento di Chimica “G. Ciamician”
- Università di Bologna
- Italy
| | - Margherita Bazzoni
- Dipartimento di Scienze Chimiche
- della Vita e della Sostenibilità Ambientale
- Università di Parma
- I-43124 Parma
- Italy
| | - Beatrice Cogliati
- Dipartimento di Scienze Chimiche
- della Vita e della Sostenibilità Ambientale
- Università di Parma
- I-43124 Parma
- Italy
| | - Alberto Credi
- Istituto per la Sintesi Organica e la Fotoreattività
- Consiglio Nazionale delle Ricerche
- I-40129 Bologna
- Italy
- Dipartimento di Chimica Industriale “Toso Montanari”
| | - Marco Lucarini
- Dipartimento di Chimica “G. Ciamician”
- Università di Bologna
- Italy
| | - Serena Silvi
- Dipartimento di Chimica “G. Ciamician”
- Università di Bologna
- Italy
| | - Arturo Arduini
- Dipartimento di Scienze Chimiche
- della Vita e della Sostenibilità Ambientale
- Università di Parma
- I-43124 Parma
- Italy
| | - Andrea Secchi
- Dipartimento di Scienze Chimiche
- della Vita e della Sostenibilità Ambientale
- Università di Parma
- I-43124 Parma
- Italy
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9
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Iuliano V, Ciao R, Vignola E, Talotta C, Iannece P, De Rosa M, Soriente A, Gaeta C, Neri P. Multiple threading of a triple-calix[6]arene host. Beilstein J Org Chem 2019; 15:2092-2104. [PMID: 31579081 PMCID: PMC6753684 DOI: 10.3762/bjoc.15.207] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2019] [Accepted: 08/16/2019] [Indexed: 01/05/2023] Open
Abstract
The synthesis of the triple-calix[6]arene derivative 6 in which three calix[6]arene macrocycles are linked to a central 1,3,5-trimethylbenzene moiety is reported. Derivative 6 is able to give multiple-threading processes in the presence of dialkylammonium axles. The formation of pseudo[2]rotaxane, pseudo[3]rotaxane, and pseudo[4]rotaxane by threading one, two, and three, respectively, calix-wheels of 6 has been studied by 1D and 2D NMR, DOSY, and ESI-FT-ICR MS/MS experiments. The use of a directional alkylbenzylammonium axle led to the stereoselective formation of endo-alkyl pseudo[n]rotaxane stereoisomers.
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Affiliation(s)
- Veronica Iuliano
- Laboratory of Supramolecular Chemistry, Dipartimento di Chimica e Biologia " A. Zambelli", Università di Salerno, Via Giovanni Paolo II 132, 84084 Fisciano (Salerno), Italy
| | - Roberta Ciao
- Laboratory of Supramolecular Chemistry, Dipartimento di Chimica e Biologia " A. Zambelli", Università di Salerno, Via Giovanni Paolo II 132, 84084 Fisciano (Salerno), Italy
| | - Emanuele Vignola
- Laboratory of Supramolecular Chemistry, Dipartimento di Chimica e Biologia " A. Zambelli", Università di Salerno, Via Giovanni Paolo II 132, 84084 Fisciano (Salerno), Italy
| | - Carmen Talotta
- Laboratory of Supramolecular Chemistry, Dipartimento di Chimica e Biologia " A. Zambelli", Università di Salerno, Via Giovanni Paolo II 132, 84084 Fisciano (Salerno), Italy
| | - Patrizia Iannece
- Laboratory of Supramolecular Chemistry, Dipartimento di Chimica e Biologia " A. Zambelli", Università di Salerno, Via Giovanni Paolo II 132, 84084 Fisciano (Salerno), Italy
| | - Margherita De Rosa
- Laboratory of Supramolecular Chemistry, Dipartimento di Chimica e Biologia " A. Zambelli", Università di Salerno, Via Giovanni Paolo II 132, 84084 Fisciano (Salerno), Italy
| | - Annunziata Soriente
- Laboratory of Supramolecular Chemistry, Dipartimento di Chimica e Biologia " A. Zambelli", Università di Salerno, Via Giovanni Paolo II 132, 84084 Fisciano (Salerno), Italy
| | - Carmine Gaeta
- Laboratory of Supramolecular Chemistry, Dipartimento di Chimica e Biologia " A. Zambelli", Università di Salerno, Via Giovanni Paolo II 132, 84084 Fisciano (Salerno), Italy
| | - Placido Neri
- Laboratory of Supramolecular Chemistry, Dipartimento di Chimica e Biologia " A. Zambelli", Università di Salerno, Via Giovanni Paolo II 132, 84084 Fisciano (Salerno), Italy
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10
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Bazzoni M, Zanichelli V, Casimiro L, Massera C, Credi A, Secchi A, Silvi S, Arduini A. New Geometries for Calix[6]arene-Based Rotaxanes. European J Org Chem 2019. [DOI: 10.1002/ejoc.201900211] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Margherita Bazzoni
- Dipartimento di Scienze Chimiche, della Vita e della Sostenibilità Ambientale; Università di Parma; Parco Area delle Scienze 17/A 43124 Parma Italy
| | - Valeria Zanichelli
- Dipartimento di Scienze Chimiche, della Vita e della Sostenibilità Ambientale; Università di Parma; Parco Area delle Scienze 17/A 43124 Parma Italy
| | - Lorenzo Casimiro
- Dipartimento di Chimica “G. Ciamician”; Università di Bologna; Via Selmi 2 40126 Italy
| | - Chiara Massera
- Dipartimento di Scienze Chimiche, della Vita e della Sostenibilità Ambientale; Università di Parma; Parco Area delle Scienze 17/A 43124 Parma Italy
| | - Alberto Credi
- Center for Light Activated Nanostructures (CLAN) and Dipartimento di Scienze e Tecnologie Agro-alimentari; Università di Bologna; 40127 Bologna Italy
- Istituto per la Sintesi Organica e la Fotoreattività (ISOF) - CNR Area della Ricerca di Bologna; Via P. Gobetti 101 40129 Bologna Italy
| | - Andrea Secchi
- Dipartimento di Scienze Chimiche, della Vita e della Sostenibilità Ambientale; Università di Parma; Parco Area delle Scienze 17/A 43124 Parma Italy
| | - Serena Silvi
- Dipartimento di Chimica “G. Ciamician”; Università di Bologna; Via Selmi 2 40126 Italy
| | - Arturo Arduini
- Dipartimento di Scienze Chimiche, della Vita e della Sostenibilità Ambientale; Università di Parma; Parco Area delle Scienze 17/A 43124 Parma Italy
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11
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Zanichelli V, Bazzoni M, Arduini A, Franchi P, Lucarini M, Ragazzon G, Secchi A, Silvi S. Redox-Switchable Calix[6]arene-Based Isomeric Rotaxanes. Chemistry 2018; 24:12370-12382. [DOI: 10.1002/chem.201800496] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2018] [Indexed: 11/10/2022]
Affiliation(s)
- Valeria Zanichelli
- Dipartimento di Scienze Chimiche, della Vita e della; Sostenibilità Ambientale; Università di Parma; Parco Area delle Scienze 17/A 43124 Parma Italy
| | - Margherita Bazzoni
- Dipartimento di Scienze Chimiche, della Vita e della; Sostenibilità Ambientale; Università di Parma; Parco Area delle Scienze 17/A 43124 Parma Italy
| | - Arturo Arduini
- Dipartimento di Scienze Chimiche, della Vita e della; Sostenibilità Ambientale; Università di Parma; Parco Area delle Scienze 17/A 43124 Parma Italy
| | - Paola Franchi
- Dipartimento di Chimica “G. Ciamician”; Università di Bologna; Via Selmi 2 40126 Bologna Italy
| | - Marco Lucarini
- Dipartimento di Chimica “G. Ciamician”; Università di Bologna; Via Selmi 2 40126 Bologna Italy
| | - Giulio Ragazzon
- Dipartimento di Chimica “G. Ciamician”; Università di Bologna; Via Selmi 2 40126 Bologna Italy
- Dipartimento di Scienze Chimiche; Università di Padova; via Marzolo 1 35131 Padova Italy
| | - Andrea Secchi
- Dipartimento di Scienze Chimiche, della Vita e della; Sostenibilità Ambientale; Università di Parma; Parco Area delle Scienze 17/A 43124 Parma Italy
| | - Serena Silvi
- Dipartimento di Chimica “G. Ciamician”; Università di Bologna; Via Selmi 2 40126 Bologna Italy
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12
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Remote electrochemical modulation of pK a in a rotaxane by co-conformational allostery. Proc Natl Acad Sci U S A 2017; 115:9385-9390. [PMID: 29255033 DOI: 10.1073/pnas.1712783115] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Allosteric control, one of Nature's most effective ways to regulate functions in biomolecular machinery, involves the transfer of information between distant sites. The mechanistic details of such a transfer are still an object of intensive investigation and debate, and the idea that intramolecular communication could be enabled by dynamic processes is gaining attention as a complement to traditional explanations. Mechanically interlocked molecules, owing to the particular kind of connection between their components and the resulting dynamic behavior, are attractive systems to investigate allosteric mechanisms and exploit them to develop functionalities with artificial species. We show that the pKa of an ammonium site located on the axle component of a [2]rotaxane can be reversibly modulated by changing the affinity of a remote recognition site for the interlocked crown ether ring through electrochemical stimulation. The use of a reversible ternary redox switch enables us to set the pKa to three different values, encompassing more than seven units. Our results demonstrate that in the axle the two sites do not communicate, and that in the rotaxane the transfer of information between them is made possible by the shuttling of the ring, that is, by a dynamic intramolecular process. The investigated coupling of electron- and proton-transfer reactions is reminiscent of the operation of the protein complex I of the respiratory chain.
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La Manna P, Talotta C, Gaeta C, Soriente A, De Rosa M, Neri P. Threading of an Inherently Directional Calixarene Wheel with Oriented Ammonium Axles. J Org Chem 2017; 82:8973-8983. [PMID: 28799754 DOI: 10.1021/acs.joc.7b01388] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The threading of monostoppered alkylbenzylammonium axles 7+ and 8+ with the calix[6]-wheel 3 can occur by both routes of entering the macrocycle 3 in the cone conformation: passage through the upper rim and the through the lower rim. Thus, under thermodynamic conditions, with both the axles 7+ and 8+, the two possible orientations of calix[2]pseudorotaxane, namely, endo-benzyl and endo-alkyl, are formed by a stereoselectivity controlled by the endo-alkyl rule. Interestingly, by 1H NMR monitoring of the threading process between 8+ and 3, we revealed two calix[2]pseudorotaxane isomers in which the calix-wheel adopts 1,2,3-alternate and cone conformations, which represent the kinetic and thermodynamic species, respectively. Finally, the synthesis of ammonium-based oriented calix[2]rotaxane is here described.
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Affiliation(s)
- Pellegrino La Manna
- Dipartimento di Chimica e Biologia "A. Zambelli", Università di Salerno , Via Giovanni Paolo II 132, I-84084 Fisciano, Salerno, Italy
| | - Carmen Talotta
- Dipartimento di Chimica e Biologia "A. Zambelli", Università di Salerno , Via Giovanni Paolo II 132, I-84084 Fisciano, Salerno, Italy
| | - Carmine Gaeta
- Dipartimento di Chimica e Biologia "A. Zambelli", Università di Salerno , Via Giovanni Paolo II 132, I-84084 Fisciano, Salerno, Italy
| | - Annunziata Soriente
- Dipartimento di Chimica e Biologia "A. Zambelli", Università di Salerno , Via Giovanni Paolo II 132, I-84084 Fisciano, Salerno, Italy
| | - Margherita De Rosa
- Dipartimento di Chimica e Biologia "A. Zambelli", Università di Salerno , Via Giovanni Paolo II 132, I-84084 Fisciano, Salerno, Italy
| | - Placido Neri
- Dipartimento di Chimica e Biologia "A. Zambelli", Università di Salerno , Via Giovanni Paolo II 132, I-84084 Fisciano, Salerno, Italy
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Zanichelli V, Ragazzon G, Orlandini G, Venturi M, Credi A, Silvi S, Arduini A, Secchi A. Efficient active-template synthesis of calix[6]arene-based oriented pseudorotaxanes and rotaxanes. Org Biomol Chem 2017; 15:6753-6763. [PMID: 28766652 DOI: 10.1039/c7ob01642e] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
A substrate can modify its chemical features, including a change of its reactivity, as a consequence of non-covalent interactions upon inclusion within a molecular host. Since the rise of supramolecular chemistry, this phenomenon has stimulated the ingenuity of scientists to emulate the function of enzymes by designing supramolecular systems in which the energetics and selectivity of reactions can be manipulated through programmed host-guest interactions and/or steric confinement. In this paper we investigate how the engulfment of a positively charged pyridinium-based guest inside the π-rich cavity of a tris-(N-phenylureido)calix[6]arene host affects its reactivity towards a SN2 reaction. We found that the alkylation of complexed substrates leads to the formation of pseudorotaxanes and rotaxanes with faster kinetics and higher yields with respect to the standard procedures exploited so far. More importantly, the strategy described here expands the range of efficient synthetic routes for the formation of mechanically interlocked species with a strict control of the mutual orientation of their non-symmetric molecular components.
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Affiliation(s)
- Valeria Zanichelli
- Dipartimento di Scienze Chimiche, della Vita e della Sostenibilità Ambientale, Università di Parma, Parco Area delle Scienze 17/A, I-43124 Parma, Italy.
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15
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Orlandini G, Ragazzon G, Zanichelli V, Secchi A, Silvi S, Venturi M, Arduini A, Credi A. Covalent capture of oriented calix[6]arene rotaxanes by a metal-free active template approach. Chem Commun (Camb) 2017; 53:6172-6174. [DOI: 10.1039/c7cc02859h] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A rotaxane with predetermined orientation of its nonsymmetric components is obtained by a rim-selective active template effect exerted by a calix[6]arene.
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Affiliation(s)
- Guido Orlandini
- Dipartimento di Scienze Chimiche
- della Vita e della Sostenibilità Ambientale
- Università di Parma
- I-43124 Parma
- Italy
| | - Giulio Ragazzon
- Dipartimento di Chimica “G. Ciamician”
- Università di Bologna
- 40126 Bologna
- Italy
| | - Valeria Zanichelli
- Dipartimento di Scienze Chimiche
- della Vita e della Sostenibilità Ambientale
- Università di Parma
- I-43124 Parma
- Italy
| | - Andrea Secchi
- Dipartimento di Scienze Chimiche
- della Vita e della Sostenibilità Ambientale
- Università di Parma
- I-43124 Parma
- Italy
| | - Serena Silvi
- Dipartimento di Chimica “G. Ciamician”
- Università di Bologna
- 40126 Bologna
- Italy
| | - Margherita Venturi
- Dipartimento di Chimica “G. Ciamician”
- Università di Bologna
- 40126 Bologna
- Italy
- Istituto per la Sintesi Organica e la Fotoreattività
| | - Arturo Arduini
- Dipartimento di Scienze Chimiche
- della Vita e della Sostenibilità Ambientale
- Università di Parma
- I-43124 Parma
- Italy
| | - Alberto Credi
- Istituto per la Sintesi Organica e la Fotoreattività
- Consiglio Nazionale delle Ricerche
- 40129 Bologna
- Italy
- Dipartimento di Scienze e Tecnologie Agro-alimentari
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Yu G, Suzaki Y, Osakada K. Ferrocene-containing [1]-, [2]-, [3]- and [4]rotaxanes synthesized from a common precursor. RSC Adv 2016. [DOI: 10.1039/c6ra05688a] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
[1]-, [2]-, [3]- and [4]rotaxanes were synthesized by reaction of azide compounds with dialkylammonium with ferrocenyl and alkynyl terminal groups.
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Affiliation(s)
- Gilbert Yu
- Chemical Resources Laboratory R1-3
- Tokyo Institute of Technology
- Yokohama
- Japan
- Ateneo de Manila University
| | - Yuji Suzaki
- Chemical Resources Laboratory R1-3
- Tokyo Institute of Technology
- Yokohama
- Japan
| | - Kohtaro Osakada
- Chemical Resources Laboratory R1-3
- Tokyo Institute of Technology
- Yokohama
- Japan
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17
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Catalán AC, Tiburcio J. Self-assembly of pseudo-rotaxane and rotaxane complexes using an electrostatic slippage approach. Chem Commun (Camb) 2016; 52:9526-9. [DOI: 10.1039/c6cc04619c] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The protonation of a cyclic tertiary amine, integrated into the structure of a dumbbell-shaped guest molecule, accelerates the sliding of the guest through the cavity of a crown ether macrocycle to yield a stable pseudo-rotaxane complex.
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Affiliation(s)
- Aldo C. Catalán
- Departamento de Química
- Centro de Investigación y de Estudios Avanzados (Cinvestav)
- Ciudad de Mexico
- Mexico
| | - Jorge Tiburcio
- Departamento de Química
- Centro de Investigación y de Estudios Avanzados (Cinvestav)
- Ciudad de Mexico
- Mexico
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