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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Nandi M, Bej S, Jana T, Ghosh P. From construction to application of a new generation of interlocked molecules composed of heteroditopic wheels. Chem Commun (Camb) 2023. [PMID: 38015500 DOI: 10.1039/d3cc03778a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2023]
Abstract
Over the last few decades, research on mechanically interlocked molecules has significantly evolved owing to their unique structural features and interesting properties. A substantial percentage of the reported works have focused on the synthetic strategies, leading to the preparation of functional MIMs for their applications in the chemical, materials, and biomedical sciences. Importantly, various macrocyclic wheels with specific heteroditopicity (including phenanthroline, amide, amine, oxy-ether, isophthalamide, calixarene and triazole) and threading axles (bipyridine, phenanthroline, pyridinium, triazolium, etc.) have been designed to synthesize targeted multifunctional mononuclear/multinuclear pseudorotaxanes, rotaxanes and catenanes. The structural uniqueness of these interlocked systems is advantageous owing to the presence of mechanical bonds with specific three-dimensional cavities. Furthermore, their multi-functionalities and preorganised structural entities exhibit a high potential for versatile applications, like switching, shuttling, dynamic properties, recognition and sensing. In this feature article, we describe some of the most recent advances in the construction and chemical behaviour of a new generation of interlocked molecules, primarily focusing on heteroditopic wheels and their applications in different directions of the modern research area. Furthermore, we outline the future prospects and significant perspectives of the new generation heteroditopic wheel based interlocked molecules in different emerging areas of science.
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Affiliation(s)
- Mandira Nandi
- School of Chemical Sciences, Indian Association for the Cultivation of Science, Kolkata 700032, India.
| | - Somnath Bej
- School of Chemical Sciences, Indian Association for the Cultivation of Science, Kolkata 700032, India.
| | - Tarun Jana
- School of Chemical Sciences, Indian Association for the Cultivation of Science, Kolkata 700032, India.
| | - Pradyut Ghosh
- School of Chemical Sciences, Indian Association for the Cultivation of Science, Kolkata 700032, India.
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5
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Andreoni L, Beneventi GM, Giovanardi G, Cera G, Credi A, Arduini A, Secchi A, Silvi S. A Multiresponsive Calix[6]arene Pseudorotaxane Empowered by Fluorophoric Dansyl Groups. Chemistry 2023; 29:e202203472. [PMID: 36929373 DOI: 10.1002/chem.202203472] [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: 11/08/2022] [Indexed: 03/18/2023]
Abstract
We report the synthesis and characterization, by means of NMR and UV-visible spectroscopy and electrochemical techniques, of a dansyl calix[6]arene derivative and of its pseudorotaxane complex with a bipyridinium-based axle. This novel macrocycle shows remarkable complexation ability, in analogy with parent compounds, while the dansyl moieties impart valuable features to the system. Indeed, these units: i) signal the state of the system by fluorescence; ii) can be reversibly protonated, enabling the modulation of the complexation abilities of the macrocycle; iii) participate in photoinduced electron transfer processes, which may be exploited to tune the stability of the supramolecular complex. Therefore, in this multiresponsive pseudorotaxane, the threading and de-threading motions of the molecular components can be modulated either by protonation of the calixarene host or by reduction of the bipyridinium guest, which can be accomplished both by electrochemical reduction and via photoinduced electron transfer. Overall, three orthogonal and reversible stimuli can be used to induce molecular movements of the pseudorotaxane components.
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Affiliation(s)
- Leonardo Andreoni
- Dipartimento di Chimica "G. Ciamician", Università di Bologna, Via Selmi 2, 40126, Bologna, Italy.,CLAN-Center for Light Activated Nanostructures, Istituto per la Sintesi Organica e la Fotoreattività, Consiglio Nazionale delle Ricerche, Via Gobetti 101, 40129, Bologna, Italy
| | | | - Gabriele Giovanardi
- Dipartimento di Scienze Chimiche della Vita e della Sostenibilità Ambientale, Università di Parma, Parco Area delle Scienze 17/A, 43124, Parma, Italy
| | - Gianpiero Cera
- Dipartimento di Scienze Chimiche della Vita e della Sostenibilità Ambientale, Università di Parma, Parco Area delle Scienze 17/A, 43124, Parma, Italy
| | - Alberto Credi
- CLAN-Center for Light Activated Nanostructures, Istituto per la Sintesi Organica e la Fotoreattività, Consiglio Nazionale delle Ricerche, Via Gobetti 101, 40129, Bologna, Italy.,Dipartimento di Chimica Industriale "Toso Montanari", Università di Bologna, Viale del Risorgimento 4, 40136, Bologna, 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
| | - 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.,CLAN-Center for Light Activated Nanostructures, Istituto per la Sintesi Organica e la Fotoreattività, Consiglio Nazionale delle Ricerche, Via Gobetti 101, 40129, Bologna, Italy
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6
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Cester Bonati F, Bazzoni M, Baccini C, Zanichelli V, Orlandini G, Arduini A, Cera G, Secchi A. Calix[6]arene-Based [3]Rotaxanes as Prototypes for the Template Synthesis of Molecular Capsules. MOLECULES (BASEL, SWITZERLAND) 2023; 28:molecules28020595. [PMID: 36677647 PMCID: PMC9864859 DOI: 10.3390/molecules28020595] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/18/2022] [Revised: 12/24/2022] [Accepted: 01/01/2023] [Indexed: 01/11/2023]
Abstract
In this work, the ability of several bis-viologen axles to thread a series of heteroditopic tris(N-phenylureido)calix[6]arene wheels to give interwoven supramolecular complexes to the [3]pseudorotaxane type was studied. The unidirectionality of the threading process inside these nonsymmetric wheels allows the formation of highly preorganised [3]pseudorotaxane and [3]rotaxane species in which the macrocycles phenylureido moieties, functionalised with either ester, carboxylic, or hydroxymethyl groups, are facing each other. As verified by NMR and semiempirical computational studies, these latter compounds possess the correct spatial arrangement of their subcomponents, which could lead, in principle, upon proper bridging reaction, to the realisation of upper-to-upper molecular capsules that are based on calix[6]arene derivatives.
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7
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Huang Q, Cai Z, Li W, Chen R, Zhang W, Jin K, Zhao Y, Li Y, Sun T. Novel, Selective Calix[6]Arene - Polyethylene Glycol (C6A-PEG) Stationary Phase for Capillary Gas Chromatography (GC). ANAL LETT 2022. [DOI: 10.1080/00032719.2022.2143794] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Affiliation(s)
- Qiuchen Huang
- Liaoning Province Professional and Technical Innovation Center for Fine Chemical Engineering of Aromatics Downstream, School of Petrochemical Engineering, Shenyang University of Technology, Liaoyang, China
| | - Zhiqiang Cai
- Liaoning Province Professional and Technical Innovation Center for Fine Chemical Engineering of Aromatics Downstream, School of Petrochemical Engineering, Shenyang University of Technology, Liaoyang, China
| | - Wei Li
- Liaoning Province Professional and Technical Innovation Center for Fine Chemical Engineering of Aromatics Downstream, School of Petrochemical Engineering, Shenyang University of Technology, Liaoyang, China
| | - Ruonan Chen
- Liaoning Province Professional and Technical Innovation Center for Fine Chemical Engineering of Aromatics Downstream, School of Petrochemical Engineering, Shenyang University of Technology, Liaoyang, China
| | - Wei Zhang
- Liaoning Province Professional and Technical Innovation Center for Fine Chemical Engineering of Aromatics Downstream, School of Petrochemical Engineering, Shenyang University of Technology, Liaoyang, China
| | - Keyun Jin
- College of Chemistry and Chemical Engineering, Henan Key Laboratory of Function-Oriented Porous Materials, Luoyang Normal University, Luoyang, China
| | - Yi Zhao
- College of Chemistry and Chemical Engineering, Henan Key Laboratory of Function-Oriented Porous Materials, Luoyang Normal University, Luoyang, China
| | - Yiwen Li
- College of Chemistry and Chemical Engineering, Henan Key Laboratory of Function-Oriented Porous Materials, Luoyang Normal University, Luoyang, China
| | - Tao Sun
- College of Chemistry and Chemical Engineering, Henan Key Laboratory of Function-Oriented Porous Materials, Luoyang Normal University, Luoyang, China
- Hebei Key Laboratory of Heterocyclic Compounds, Handan University, Handan, China
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8
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Bonati FC, Secchi A, Cera G. Recent advances with calix[6]- and calix[8]arene organometallic catalysts. Tetrahedron Lett 2022. [DOI: 10.1016/j.tetlet.2022.154221] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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9
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Giovanardi G, Balestri D, Secchi A, Cera G. Diametric calix[6]arene gold(I) catalysts for intramolecular cyclopropanations of 1,6-dienynes. Org Biomol Chem 2022; 20:6464-6472. [PMID: 35894952 DOI: 10.1039/d2ob01074g] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
We report a solid-state structural investigation of diametric calix[6]arene-based phosphine gold(I) cavitands which are characterised by two specific, different 1,2,3-alternate conformations in solution and in the solid state. The effect of the specific orientation of phosphines, with respect to macrocycles, was studied in intramolecular cyclopropanation of 1,6-dienynes. The general applicability of these catalysts was disclosed, delivering a family of polycycles with high yields and functional group tolerance.
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Affiliation(s)
- Gabriele Giovanardi
- Dipartimento di Scienze Chimiche, della Vita e della Sostenibilità Ambientale, Università di Parma, Parco Area delle Scienze 17/A, 43124 Parma, Italy.
| | - Davide Balestri
- Dipartimento di Scienze Chimiche, della Vita e della Sostenibilità Ambientale, Università di Parma, Parco Area delle Scienze 17/A, 43124 Parma, 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.
| | - Gianpiero Cera
- 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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10
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Giovanardi G, Secchi A, Arduini A, Cera G. Diametric calix[6]arene-based phosphine gold(I) cavitands. Beilstein J Org Chem 2022; 18:190-196. [PMID: 35233258 PMCID: PMC8848346 DOI: 10.3762/bjoc.18.21] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2021] [Accepted: 02/02/2022] [Indexed: 12/18/2022] Open
Abstract
We report the synthesis and characterization, in low polarity solvents, of a novel class of diametric phosphine gold(I) cavitands characterized by a 1,2,3-alternate geometry. Preliminary catalytic studies were performed on a model cycloisomerization of 1,6-enynes as a function of the relative orientation of the bonded gold(I) nuclei with respect to the macrocyclic cavity.
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Affiliation(s)
- Gabriele Giovanardi
- Dipartimento di Scienze Chimiche, della Vita e della Sostenibilità Ambientale, Università di Parma, Parco Area delle Scienze 17/A, 43124 Parma, 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
| | - Arturo Arduini
- Dipartimento di Scienze Chimiche, della Vita e della Sostenibilità Ambientale, Università di Parma, Parco Area delle Scienze 17/A, 43124 Parma, Italy
| | - Gianpiero Cera
- 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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Cera G, Bazzoni M, Andreoni L, Cester Bonati F, Massera C, Silvi S, Credi A, Secchi A, Arduini A. Thioureidocalix[6]arenes Pseudorotaxanes. European J Org Chem 2021. [DOI: 10.1002/ejoc.202101080] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Gianpiero Cera
- 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
| | - Leonardo Andreoni
- Dipartimento di Chimica “G. Ciamician” Università di Bologna Via Selmi 2 40126 Bologna Italy
- CLAN-Center for Light Activated Nanostructures Istituto per la Sintesi Organica e la Fotoreattività Consiglio Nazionale delle Ricerche Via Gobetti 101 40129 Bologna Italy
| | - Federica Cester Bonati
- Dipartimento di Scienze Chimiche della Vita e della Sostenibilità Ambientale Università di Parma Parco Area delle Scienze 17/A 43124 Parma 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
| | - Serena Silvi
- Dipartimento di Chimica “G. Ciamician” Università di Bologna Via Selmi 2 40126 Bologna Italy
- CLAN-Center for Light Activated Nanostructures Istituto per la Sintesi Organica e la Fotoreattività Consiglio Nazionale delle Ricerche Via Gobetti 101 40129 Bologna Italy
| | - Alberto Credi
- CLAN-Center for Light Activated Nanostructures Istituto per la Sintesi Organica e la Fotoreattività Consiglio Nazionale delle Ricerche Via Gobetti 101 40129 Bologna Italy
- Dipartimento di Chimica Industriale “Toso Montanari” Università di Bologna Viale del Risorgimento 4 40136 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
| | - 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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12
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Cera G, Giovanardi G, Secchi A, Arduini A. Merging Molecular Recognition and Gold(I) Catalysis with Triphoscalix[6]arene Ligands. Chemistry 2021; 27:10261-10266. [PMID: 34002908 DOI: 10.1002/chem.202101323] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2021] [Indexed: 12/17/2022]
Abstract
We report the synthesis and characterization of novel triphosphine calix[6]arene ligands. These supramolecular wheels, with recognition features governed by the hydrogen-bonding domain, were employed to synthesize multitasking trinuclear gold(I) complexes as a new platform for the synthesis of interwoven (pseudo)rotaxane species. In parallel, the multivalent, metal-bonded upper rim displayed catalytic features promoting highly selective gold-catalyzed cycloisomerization reactions of 1,6-enynes.
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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, 43124, Parma, Italy
| | - Gabriele Giovanardi
- Dipartimento di Scienze Chimiche, della Vita e della Sostenibilità Ambientale, Università di Parma, Parco Area delle Scienze 17/A, 43124, Parma, 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
| | - 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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13
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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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