1
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Chen X, Chen H, Fraser Stoddart J. The Story of the Little Blue Box: A Tribute to Siegfried Hünig. Angew Chem Int Ed Engl 2023; 62:e202211387. [PMID: 36131604 PMCID: PMC10099103 DOI: 10.1002/anie.202211387] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2022] [Indexed: 02/02/2023]
Abstract
The tetracationic cyclophane, cyclobis(paraquat-p-phenylene), also known as the little blue box, constitutes a modular receptor that has facilitated the discovery of many host-guest complexes and mechanically interlocked molecules during the past 35 years. Its versatility in binding small π-donors in its tetracationic state, as well as forming trisradical tricationic complexes with viologen radical cations in its doubly reduced bisradical dicationic state, renders it valuable for the construction of various stimuli-responsive materials. Since the first reports in 1988, the little blue box has been featured in over 500 publications in the literature. All this research activity would not have been possible without the seminal contributions carried out by Siegfried Hünig, who not only pioneered the syntheses of viologen-containing cyclophanes, but also revealed their rich redox chemistry in addition to their ability to undergo intramolecular π-dimerization. This Review describes how his pioneering research led to the design and synthesis of the little blue box, and how this redox-active host evolved into the key component of molecular shuttles, switches, and machines.
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Affiliation(s)
- Xiao‐Yang Chen
- Department of ChemistryNorthwestern University2145 Sheridan RoadEvanstonIllinois 60208USA
| | - Hongliang Chen
- Stoddart Institute of Molecular ScienceDepartment of ChemistryZhejiang UniversityHangzhou310027China
- ZJU-Hangzhou Global Scientific and Technological Innovation CenterHangzhou311215China
| | - J. Fraser Stoddart
- Department of ChemistryNorthwestern University2145 Sheridan RoadEvanstonIllinois 60208USA
- Stoddart Institute of Molecular ScienceDepartment of ChemistryZhejiang UniversityHangzhou310027China
- ZJU-Hangzhou Global Scientific and Technological Innovation CenterHangzhou311215China
- School of ChemistryUniversity of New South WalesSydneyNSW 2052Australia
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2
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Jiao Y, Mao H, Qiu Y, Wu G, Chen H, Zhang L, Han H, Li X, Zhao X, Tang C, Chen XY, Feng Y, Stern CL, Wasielewski MR, Stoddart JF. Mechanical Bond-Assisted Full-Spectrum Investigation of Radical Interactions. J Am Chem Soc 2022; 144:23168-23178. [DOI: 10.1021/jacs.2c10882] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Affiliation(s)
- Yang Jiao
- Department of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208, United States
| | - Haochuan Mao
- Department of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208, United States
- Institute for Sustainability and Energy at Northwestern, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208, United States
| | - Yunyan Qiu
- Department of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208, United States
| | - Guangcheng Wu
- Department of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208, United States
| | - Hongliang Chen
- Department of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208, United States
- Stoddart Institute of Molecular Science, Department of Chemistry, Zhejiang University, Hangzhou 310027, China
- ZJU-Hangzhou Global Scientific and Technological Innovation Center, Hangzhou 311215, China
| | - Long Zhang
- Department of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208, United States
| | - Han Han
- Department of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208, United States
| | - Xuesong Li
- Department of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208, United States
| | - Xingang Zhao
- Department of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208, United States
| | - Chun Tang
- Department of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208, United States
| | - Xiao-Yang Chen
- Department of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208, United States
| | - Yuanning Feng
- Department of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208, United States
| | - Charlotte L. Stern
- Department of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208, United States
| | - Michael R. Wasielewski
- Department of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208, United States
- Institute for Sustainability and Energy at Northwestern, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208, United States
| | - J. Fraser Stoddart
- Department of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208, United States
- Stoddart Institute of Molecular Science, Department of Chemistry, Zhejiang University, Hangzhou 310027, China
- ZJU-Hangzhou Global Scientific and Technological Innovation Center, Hangzhou 311215, China
- School of Chemistry, University of New South Wales, Sydney, NSW 2052, Australia
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3
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Abstract
Molecular recognition1-4 and supramolecular assembly5-8 cover a broad spectrum9-11 of non-covalently orchestrated phenomena between molecules. Catalysis12 of such processes, however, unlike that for the formation of covalent bonds, is limited to approaches13-16 that rely on sophisticated catalyst design. Here we establish a simple and versatile strategy to facilitate molecular recognition by extending electron catalysis17, which is widely applied18-21 in synthetic covalent chemistry, into the realm of supramolecular non-covalent chemistry. As a proof of principle, we show that the formation of a trisradical complex22 between a macrocyclic host and a dumbbell-shaped guest-a molecular recognition process that is kinetically forbidden under ambient conditions-can be accelerated substantially on the addition of catalytic amounts of a chemical electron source. It is, therefore, electrochemically possible to control23 the molecular recognition temporally and produce a nearly arbitrary molar ratio between the substrates and complexes ranging between zero and the equilibrium value. Such kinetically stable supramolecular systems24 are difficult to obtain precisely by other means. The use of the electron as a catalyst in molecular recognition will inspire chemists and biologists to explore strategies that can be used to fine-tune non-covalent events, control assembly at different length scales25-27 and ultimately create new forms of complex matter28-30.
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4
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Chen X, Mao H, Feng Y, Cai K, Shen D, Wu H, Zhang L, Zhao X, Chen H, Song B, Jiao Y, Wu Y, Stern CL, Wasielewski MR, Stoddart JF. Radically Enhanced Dual Recognition. Angew Chem Int Ed Engl 2021. [DOI: 10.1002/ange.202109647] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Xiao‐Yang Chen
- Department of Chemistry Northwestern University 2145 Sheridan Road Evanston IL 60208 USA
| | - Haochuan Mao
- Department of Chemistry Northwestern University 2145 Sheridan Road Evanston IL 60208 USA
- Institute for Sustainability and Energy at Northwestern Northwestern University 2145 Sheridan Road Evanston IL 60208 USA
| | - Yuanning Feng
- Department of Chemistry Northwestern University 2145 Sheridan Road Evanston IL 60208 USA
| | - Kang Cai
- Department of Chemistry Nankai University 94 Weijin Road, Nankai District Tianjin 300071 China
| | - Dengke Shen
- Institutes of Physical Science and Information Technology Anhui University Hefei 230601 China
| | - Huang Wu
- Department of Chemistry Northwestern University 2145 Sheridan Road Evanston IL 60208 USA
| | - Long Zhang
- Department of Chemistry Northwestern University 2145 Sheridan Road Evanston IL 60208 USA
| | - Xingang Zhao
- Department of Chemistry Northwestern University 2145 Sheridan Road Evanston IL 60208 USA
| | - Hongliang Chen
- Department of Chemistry Northwestern University 2145 Sheridan Road Evanston IL 60208 USA
| | - Bo Song
- Department of Chemistry Northwestern University 2145 Sheridan Road Evanston IL 60208 USA
| | - Yang Jiao
- Department of Chemistry Northwestern University 2145 Sheridan Road Evanston IL 60208 USA
| | - Yong Wu
- Department of Chemistry Northwestern University 2145 Sheridan Road Evanston IL 60208 USA
| | - Charlotte L. Stern
- Department of Chemistry Northwestern University 2145 Sheridan Road Evanston IL 60208 USA
| | - Michael R. Wasielewski
- Department of Chemistry Northwestern University 2145 Sheridan Road Evanston IL 60208 USA
- Institute for Sustainability and Energy at Northwestern Northwestern University 2145 Sheridan Road Evanston IL 60208 USA
| | - J. Fraser Stoddart
- Department of Chemistry Northwestern University 2145 Sheridan Road Evanston IL 60208 USA
- School of Chemistry University of New South Wales Sydney NSW 2052 Australia
- Stoddart Institute of Molecular Science Department of Chemistry Zhejiang University Hangzhou 310027 China
- ZJU-Hangzhou Global Scientific and Technological Innovation Center Hangzhou 311215 China
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5
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Chowdhury S, Reynard-Feytis Q, Roizard C, Frath D, Chevallier F, Bucher C, Gibaud T. Light-Controlled Aggregation and Gelation of Viologen-Based Coordination Polymers. J Phys Chem B 2021; 125:12063-12071. [PMID: 34677961 DOI: 10.1021/acs.jpcb.1c06090] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Ditopic bis-(triazole/pyridine)viologens are bidentate ligands that self-assemble into coordination polymers. In such photo-responsive materials, light irradiation initiates photo-induced electron transfer to generate π-radicals that can self-associate to form π-dimers. This leads to a cascade of events: processes at the supramolecular scale associated with mechanical and structural transition at the macroscopic scale. By tuning the irradiation power and duration, we evidence the formation of aggregates and gels. Using microscopy, we show that the aggregates are dense, polydisperse, micron-sized, spindle-shaped particles which grow in time. Using microscopy and time-resolved micro-rheology, we follow the gelation kinetics which leads to a gel characterized by a correlation length of a few microns and a weak elastic modulus. The analysis of the aggregates and the gel states vouch for an arrested phase separation process, a new scenario to supramolecular systems.
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Affiliation(s)
- Shagor Chowdhury
- Laboratoire de Chimie, Université de Lyon, Ens de Lyon, CNRS UMR 5182, F69342 Lyon, France
| | - Quentin Reynard-Feytis
- Laboratoire de Chimie, Université de Lyon, Ens de Lyon, CNRS UMR 5182, F69342 Lyon, France
| | - Clément Roizard
- Laboratoire de Chimie, Université de Lyon, Ens de Lyon, CNRS UMR 5182, F69342 Lyon, France
| | - Denis Frath
- Laboratoire de Chimie, Université de Lyon, Ens de Lyon, CNRS UMR 5182, F69342 Lyon, France
| | - Floris Chevallier
- Laboratoire de Chimie, Université de Lyon, Ens de Lyon, CNRS UMR 5182, F69342 Lyon, France
| | - Christophe Bucher
- Laboratoire de Chimie, Université de Lyon, Ens de Lyon, CNRS UMR 5182, F69342 Lyon, France
| | - Thomas Gibaud
- Laboratoire de Physique, Université de Lyon, Ens de Lyon, University Claude Bernard, CNRS, F69342 Lyon, France
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6
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Chen XY, Mao H, Feng Y, Cai K, Shen D, Wu H, Zhang L, Zhao X, Chen H, Song B, Jiao Y, Wu Y, Stern CL, Wasielewski MR, Stoddart JF. Radically Enhanced Dual Recognition. Angew Chem Int Ed Engl 2021; 60:25454-25462. [PMID: 34342116 DOI: 10.1002/anie.202109647] [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: 07/19/2021] [Indexed: 11/08/2022]
Abstract
Complexation between a viologen radical cation (V.+ ) and cyclobis(paraquat-p-phenylene) diradical dication (CBPQT2(.+) ) has been investigated and utilized extensively in the construction of mechanically interlocked molecules (MIMs) and artificial molecular machines (AMMs). The selective recognition of a pair of V.+ using radical-pairing interactions, however, remains a formidable challenge. Herein, we report the efficient encapsulation of two methyl viologen radical cations (MV.+ ) in a size-matched bisradical dicationic host - namely, cyclobis(paraquat-2,6-naphthalene)2(.+) , i.e., CBPQN2(.+) . Central to this dual recognition process was the choice of 2,6-bismethylenenaphthalene linkers for incorporation into the bisradical dicationic host. They provide the space between the two bipyridinium radical cations in CBPQN2(.+) suitable for binding two MV.+ with relatively short (3.05-3.25 Å) radical-pairing distances. The size-matched bisradical dicationic host was found to exhibit highly selective and cooperative association with the two MV.+ in MeCN at room temperature. The formation of the tetrakisradical tetracationic inclusion complex - namely, [(MV)2 ⊂CBPQN]4( .+) - in MeCN was confirmed by VT 1 H NMR, as well as by EPR spectroscopy. The solid-state superstructure of [(MV)2 ⊂CBPQN]4( .+) reveals an uneven distribution of the binding distances (3.05, 3.24, 3.05 Å) between the three different V.+ , suggesting that localization of the radical-pairing interactions has a strong influence on the packing of the two MV.+ inside the bisradical dicationic host. Our findings constitute a rare example of binding two radical guests with high affinity and cooperativity using host-guest radical-pairing interactions. Moreover, they open up possibilities of harnessing the tetrakisradical tetracationic inclusion complex as a new, orthogonal and redox-switchable recognition motif for the construction of MIMs and AMMs.
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Affiliation(s)
- Xiao-Yang Chen
- Department of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, IL, 60208, USA
| | - Haochuan Mao
- Department of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, IL, 60208, USA.,Institute for Sustainability and Energy at Northwestern, Northwestern University, 2145 Sheridan Road, Evanston, IL, 60208, USA
| | - Yuanning Feng
- Department of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, IL, 60208, USA
| | - Kang Cai
- Department of Chemistry, Nankai University, 94 Weijin Road, Nankai District, Tianjin, 300071, China
| | - Dengke Shen
- Institutes of Physical Science and Information Technology, Anhui University, Hefei, 230601, China
| | - Huang Wu
- Department of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, IL, 60208, USA
| | - Long Zhang
- Department of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, IL, 60208, USA
| | - Xingang Zhao
- Department of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, IL, 60208, USA
| | - Hongliang Chen
- Department of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, IL, 60208, USA
| | - Bo Song
- Department of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, IL, 60208, USA
| | - Yang Jiao
- Department of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, IL, 60208, USA
| | - Yong Wu
- Department of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, IL, 60208, USA
| | - Charlotte L Stern
- Department of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, IL, 60208, USA
| | - Michael R Wasielewski
- Department of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, IL, 60208, USA.,Institute for Sustainability and Energy at Northwestern, Northwestern University, 2145 Sheridan Road, Evanston, IL, 60208, USA
| | - J Fraser Stoddart
- Department of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, IL, 60208, USA.,School of Chemistry, University of New South Wales, Sydney, NSW, 2052, Australia.,Stoddart Institute of Molecular Science, Department of Chemistry, Zhejiang University, Hangzhou, 310027, China.,ZJU-Hangzhou Global Scientific and Technological Innovation Center, Hangzhou, 311215, China
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7
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Cai K, Zhang L, Astumian RD, Stoddart JF. Radical-pairing-induced molecular assembly and motion. Nat Rev Chem 2021; 5:447-465. [PMID: 37118435 DOI: 10.1038/s41570-021-00283-4] [Citation(s) in RCA: 36] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/16/2021] [Indexed: 12/25/2022]
Abstract
Radical-pairing interactions between conjugated organic π-radicals are relative newcomers to the inventory of molecular recognition motifs explored in supramolecular chemistry. The unique electronic, magnetic, optical and redox-responsive properties of the conjugated π-radicals render molecules designed with radical-pairing interactions useful for applications in various areas of chemistry and materials science. In particular, the ability to control formation of radical cationic or anionic species, by redox stimulation, provides a flexible trigger for directed assembly and controlled molecular motions, as well as a convenient means of inputting energy to fuel non-equilibrium processes. In this Review, we provide an overview of different examples of radical-pairing-based recognition processes and of their emerging use in (1) supramolecular assembly, (2) templation of mechanically interlocked molecules, (3) stimuli-controlled molecular switches and, by incorporation of kinetic asymmetry in the design, (4) the creation of unidirectional molecular transporters based on pumping cassettes powered by fuelled switching of radical-pairing interactions. We conclude the discussion with an outlook on future directions for the field.
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8
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Jiao T, Qu H, Tong L, Cao X, Li H. A Self‐Assembled Homochiral Radical Cage with Paramagnetic Behaviors. Angew Chem Int Ed Engl 2021. [DOI: 10.1002/ange.202100655] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Tianyu Jiao
- Department of Chemistry Zhejiang University Hangzhou 310027 P. R. China
| | - Hang Qu
- State Key Laboratory of Physical Chemistry of Solid Surfaces iChEM and College of Chemistry and Chemical Engineering Xiamen University Xiamen 361005 China
| | - Lu Tong
- Department of Chemistry Zhejiang University Hangzhou 310027 P. R. China
| | - Xiaoyu Cao
- State Key Laboratory of Physical Chemistry of Solid Surfaces iChEM and College of Chemistry and Chemical Engineering Xiamen University Xiamen 361005 China
| | - Hao Li
- Department of Chemistry Zhejiang University Hangzhou 310027 P. R. China
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9
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Jiao T, Qu H, Tong L, Cao X, Li H. A Self-Assembled Homochiral Radical Cage with Paramagnetic Behaviors. Angew Chem Int Ed Engl 2021; 60:9852-9858. [PMID: 33651476 DOI: 10.1002/anie.202100655] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2021] [Revised: 02/14/2021] [Indexed: 12/24/2022]
Abstract
Condensation of an inherently C3 -symmetric polychlorotriphenylmethyl (PTM) radical trisaldehyde with tris(2-aminoethyl)amine (TREN) yields a [4+4] tetrahedral radical cage as a racemic pair of homochiral enantiomers in 75 % isolated yield. The structure was characterized by X-ray crystallography, confirming the homochirality of each cage framework. The homochirality results from intramolecular [CH⋅⋅⋅π] and hydrogen-bonding interactions within the cage framework. The four PTM radicals in a cage undergo weak through-space coupling. Magnetic measurements demonstrated that each cage bears 3.58 spins.
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Affiliation(s)
- Tianyu Jiao
- Department of Chemistry, Zhejiang University, Hangzhou, 310027, P. R. China
| | - Hang Qu
- State Key Laboratory of Physical Chemistry of Solid Surfaces, iChEM and College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, 361005, China
| | - Lu Tong
- Department of Chemistry, Zhejiang University, Hangzhou, 310027, P. R. China
| | - Xiaoyu Cao
- State Key Laboratory of Physical Chemistry of Solid Surfaces, iChEM and College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, 361005, China
| | - Hao Li
- Department of Chemistry, Zhejiang University, Hangzhou, 310027, P. R. China
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10
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Wang C, Wu G, Zhu J, Jiao T, Zhang Y, Li H. An Octacationic [2]Catenane Formed by Oxime Condensation: A Bistable Molecular Switch. Chempluschem 2019. [DOI: 10.1002/cplu.201900668] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Cai‐Yun Wang
- Department of Chemistry Zhejiang University Hangzhou 310027 P. R. China
| | - Guangcheng Wu
- Department of Chemistry Zhejiang University Hangzhou 310027 P. R. China
| | - Jiaqi Zhu
- Department of Chemistry Zhejiang University Hangzhou 310027 P. R. China
| | - Tianyu Jiao
- Department of Chemistry Zhejiang University Hangzhou 310027 P. R. China
| | - Yang Zhang
- Department of Chemistry Zhejiang University Hangzhou 310027 P. R. China
| | - Hao Li
- Department of Chemistry Zhejiang University Hangzhou 310027 P. R. China
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11
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Abstract
The design and synthesis of artificial molecular switches (AMSs) displaying architectures of increased complexity would constitute significant progress in meeting the challenging task of realizing artificial molecular machines (AMMs). Here, we report the synthesis and characterization of a molecular shuttle composed of a cyclobis(paraquat-4,4'-biphenylene) cyclophane ring and a dumbbell incorporating a cyclobis(paraquat-m-phenylene) cyclophane "head" and a bifurcated, tawse-like "tail" composed of two oligoether chains, each containing a 1,5-dioxynaphthalene ring. In its reduced state the ring-in-ring recognition motif, between the meta and para bisradical dicationic cyclophanes (rings), defines the [2]rotaxane, whereas in the oxidized state, the cyclobis(paraquat-4,4'-biphenylene) cyclophane encircles the two 1,5-dioxynaphthalene rings in the bifurcated "tail". The redox-controlled molecular shuttling, which can be likened to the action of a zipper in the macroscopic world, exhibits slow kinetics dampened by the opening and closing of the bifurcated "tail" of the molecular shuttle. Cyclic voltammetry reveals that this slow shuttling is associated with electrochemical hysteresis.
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Affiliation(s)
- Melissa Dumartin
- Department of Chemistry , Northwestern University , 2145 Sheridan Road , Evanston , Illinois 60208 , United States
| | - Mark C Lipke
- Department of Chemistry and Chemical Biology , Rutgers, The State University of New Jersey , 610 Taylor Road , Piscataway , New Jersey 08854 , United States
| | - J Fraser Stoddart
- Department of Chemistry , Northwestern University , 2145 Sheridan Road , Evanston , Illinois 60208 , United States.,Institute of Molecular Design and Synthesis , Tianjin University , 92 Weijin Road, Nankai District , Tianjin 300072 , P. R. China.,School of Chemistry , University of New South Wales , Sydney , NSW 2052 , Australia
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12
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Abstract
The host-guest recognition between two macrocycles to form hierarchical non-intertwined ring-in-ring assemblies remains an interesting and challenging target in noncovalent synthesis. Herein, we report the design and characterization of a box-in-box assembly on the basis of host-guest radical-pairing interactions between two rigid diradical dicationic cyclophanes. One striking feature of the box-in-box complex is its ability to host various 1,4-disubstituted benzene derivatives inside as a third component in the cavity of the smaller of the two diradical dicationic cyclophanes to produce hierarchical Russian doll like assemblies. These results highlight the utility of matching the dimensions of two different cyclophanes as an efficient approach for developing new hybrid supramolecular assemblies with radical-paired ring-in-ring complexes and smaller neutral guest molecules.
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13
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Wang Y, Cheng T, Sun J, Liu Z, Frasconi M, Goddard WA, Stoddart JF. Neighboring Component Effect in a Tri-stable [2]Rotaxane. J Am Chem Soc 2018; 140:13827-13834. [PMID: 30253106 DOI: 10.1021/jacs.8b08519] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
The redox properties of cyclobis(paraquat- p-phenylene)cyclophane (CBPQT4+) render it a uniquely variable source of recognition in the context of mechanically interlocked molecules, through aromatic donor-acceptor interactions in its fully oxidized state (CPBQT4+) and radical-pairing interactions in its partially reduced state (CBPQT2(•+)). Although it is expected that the fully reduced neutral state (CBPQT(0)) might behave as a π-donating recognition unit, resulting in a dramatic change in its binding properties when compared with the other two redox states, its role in rotaxanes has not yet been investigated. To address this challenge, we report herein the synthesis of a tri-stable [2]rotaxane in which a CBPQT4+ ring is mechanically interlocked with a dumbbell component containing five recognition sites-(i) a bipyridinium radical cation (BIPY(•+)) located centrally along the axis of the dumbbell, straddled by (ii) two tetrafluorophenylene units linked to (iii) two triazole rings. In addition to the selective recognition between (iv) the CBPQT4+ ring and the triazole units, and (v) the CBPQT2(•+) ring and the reduced BIPY(•+) unit in the dumbbell component, investigations in solution have now confirmed the presence of additional non-covalent bonding interactions between the CBPQT(0) ring, acting as a donor in its neutral state, and the two tetrafluorophenylene acceptors in the dumbbell component. The unveiling of this piece of molecular recognition in a [2]rotaxane is reminiscent of the existence in much simpler, covalently linked, organic molecules of neighboring group participation (anchimeric assistance giving way to transannular interactions) in small-, medium-, and large-membered rings.
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Affiliation(s)
- Yuping Wang
- Department of Chemistry , Northwestern University , 2145 Sheridan Road , Evanston , Illinois 60208 , United States
| | - Tao Cheng
- Materials and Process Simulation Center , California Institute of Technology , 1200 East California Boulevard , Pasadena , California 91125 , United States
| | - Junling Sun
- Department of Chemistry , Northwestern University , 2145 Sheridan Road , Evanston , Illinois 60208 , United States
| | - Zhichang Liu
- School of Science , Westlake University , 18 Shilongshan Road , Hangzhou 310024 , China
| | - Marco Frasconi
- Department of Chemical Sciences , University of Padova , Via Marzolo 1 , Padova 35131 , Italy
| | - William A Goddard
- Materials and Process Simulation Center , California Institute of Technology , 1200 East California Boulevard , Pasadena , California 91125 , United States
| | - J Fraser Stoddart
- Department of Chemistry , Northwestern University , 2145 Sheridan Road , Evanston , Illinois 60208 , United States.,Institute for Molecular Design and Synthesis , Tianjin University , 92 Weijin Road , Nankai District, Tianjin 300072 , China.,School of Chemistry , University of New South Wales , Sydney , NSW 2052 , Australia
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14
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A New Horizon for the Mechanical Bond. Chem 2018. [DOI: 10.1016/j.chempr.2018.09.016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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15
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Nguyen MT, Ferris DP, Pezzato C, Wang Y, Stoddart JF. Densely Charged Dodecacationic [3]- and Tetracosacationic Radial [5]Catenanes. Chem 2018. [DOI: 10.1016/j.chempr.2018.07.010] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
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16
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Lipke MC, Wu Y, Roy I, Wang Y, Wasielewski MR, Stoddart JF. Shuttling Rates, Electronic States, and Hysteresis in a Ring-in-Ring Rotaxane. ACS CENTRAL SCIENCE 2018; 4:362-371. [PMID: 29632882 PMCID: PMC5879476 DOI: 10.1021/acscentsci.7b00535] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/06/2017] [Indexed: 06/08/2023]
Abstract
The trisradical recognition motif between a 4,4'-bipyridinium radical cation and a cyclo-bis-4,4'-bipyridinium diradical dication has been employed previously in rotaxanes to control their nanomechanical and electronic properties. Herein, we describe the synthesis and characterization of a redox-active ring-in-ring [2]rotaxane BBR·8PF6 that employs a tetraradical variant of this recognition motif. A square-shaped bis-4,4'-bipyridinium cyclophane is mechanically interlocked around the dumbbell component of this rotaxane, and the dumbbell itself incorporates a smaller bis-4,4'-bipyridinium cyclophane into its covalently bonded structure. This small cyclophane serves as a significant impediment to the shuttling of the larger ring across the dumbbell component of BBR8+ , whereas reduction to the tetraradical tetracationic state BBR4(+•) results in strong association of the two cyclophanes driven by two radical-pairing interactions. In these respects, BBR·8PF6 exhibits qualitatively similar behavior to its predecessors that interconvert between hexacationic and trisradical tricationic states. The rigid preorganization of two bipyridinium groups within the dumbbell of BBR·8PF6 confers, however, two distinct properties upon this rotaxane: (1) the rate of shuttling is reduced significantly relative to those of its predecessors, resulting in marked electrochemical hysteresis observed by cyclic voltammetry for switching between the BBR8+/BBR4(+•) states, and (2) the formally tetraradical form of the rotaxane, BBR4(+•) , exhibits a diamagnetic ground state, which, as a result of the slow shuttling motions within BBR4(+•) , has a long enough lifetime to be characterized by 1H NMR spectroscopy.
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Affiliation(s)
- Mark C. Lipke
- Department
of Chemistry and Chemical Biology, Rutgers,
The State University of New Jersey, 610 Taylor Road, Piscataway, New Jersey 08854, United States
| | - Yilei Wu
- Department
of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208, United States
| | - Indranil Roy
- Department
of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208, United States
| | - Yuping Wang
- Department
of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208, United States
| | - Michael R. Wasielewski
- Department
of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208, United States
| | - J. Fraser Stoddart
- Department
of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208, United States
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17
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Cai LX, Li SC, Yan DN, Zhou LP, Guo F, Sun QF. Water-Soluble Redox-Active Cage Hosting Polyoxometalates for Selective Desulfurization Catalysis. J Am Chem Soc 2018. [DOI: 10.1021/jacs.8b00394] [Citation(s) in RCA: 169] [Impact Index Per Article: 28.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Affiliation(s)
- Li-Xuan Cai
- State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou 350002, PR China
| | - Shao-Chuan Li
- State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou 350002, PR China
- College of Chemistry, Liaoning University, Shenyang 110036, PR China
| | - Dan-Ni Yan
- State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou 350002, PR China
- University of Chinese
Academy of Sciences, Beijing 100049, PR China
| | - Li-Peng Zhou
- State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou 350002, PR China
| | - Fang Guo
- College of Chemistry, Liaoning University, Shenyang 110036, PR China
| | - Qing-Fu Sun
- State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou 350002, PR China
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18
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Yang YD, Sessler JL, Gong HY. Flexible imidazolium macrocycles: building blocks for anion-induced self-assembly. Chem Commun (Camb) 2018; 53:9684-9696. [PMID: 28766599 DOI: 10.1039/c7cc04661h] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
This feature article summarises recent contributions of the authors in the area of anion-induced supramolecular self-assembly. It is based on the chemistry of a set of tetracationic imidazolium macrocycles, specifically the so-called 'Texas-sized' molecular box, cyclo[2](2,6-di(1H-imidazol-1-yl)pyridine)[2](1,4-dimethylenebenzene) (14+), and its congeners, cyclo[2](2,6-di(1H-imidazol-1-yl)pyridine)[2](1,2-dimethylenebenzene) (24+), cyclo[2](2,6-di(1H-imidazol-1-yl)pyridine)[2](1,3-dimethylenebenzene) (34+), and cyclo[2](2,6-di(1H-imidazol-1-yl)pyridine)[2](2,6-dimethylenepyridine) (44+). These systems collectively have been demonstrated as being versatile building blocks that interact with organic carboxylate or sulfonate anions, as well as substrates (e.g., neutral molecules or metal cations). Most work to date has been carried out with 14+, a system that has been found to support the construction of a number of stimuli responsive self-assembled ensembles. This macrocycle and others of the 'Texas-sized' box family also show the potential to react as carbene precursors and to undergo post-synthetic modification (PSM) to produce new functional macrocycles, such as trans- and cis-cyclo[2]((Z)-N-(2-((6-(1H-imidazol-1-yl)pyridin-2-yl)amino)vinyl)formamide)[2](1,4-bismethylbenzene) (52+ and 62+, respectively). On the basis of the work reviewed in this Feature article, we propose that the imidazolium macrocycles 14+-44+ can be considered as useful tools for the construction of ensembles with environmentally responsive features, including control over self-assembly and an ability to undergo precursor-specific PSM.
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Affiliation(s)
- Yu-Dong Yang
- College of Chemistry, Beijing Normal University, Xinjiekouwaidajie 19, Beijing, 100875, P. R. China.
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19
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Wang Y, Frasconi M, Stoddart JF. Introducing Stable Radicals into Molecular Machines. ACS CENTRAL SCIENCE 2017; 3:927-935. [PMID: 28979933 PMCID: PMC5620985 DOI: 10.1021/acscentsci.7b00219] [Citation(s) in RCA: 84] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/25/2017] [Indexed: 06/07/2023]
Abstract
Ever since their discovery, stable organic radicals have received considerable attention from chemists because of their unique optical, electronic, and magnetic properties. Currently, one of the most appealing challenges for the chemical community is to develop sophisticated artificial molecular machines that can do work by consuming external energy, after the manner of motor proteins. In this context, radical-pairing interactions are important in addressing the challenge: they not only provide supramolecular assistance in the synthesis of molecular machines but also open the door to developing multifunctional systems relying on the various properties of the radical species. In this Outlook, by taking the radical cationic state of 1,1'-dialkyl-4,4'-bipyridinium (BIPY•+) as an example, we highlight our research on the art and science of introducing radical-pairing interactions into functional systems, from prototypical molecular switches to complex molecular machines, followed by a discussion of the (i) limitations of the current systems and (ii) future research directions for designing BIPY•+-based molecular machines with useful functions.
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Affiliation(s)
- Yuping Wang
- Department of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208, United States
| | - Marco Frasconi
- Department of Chemical Sciences, University of Padova, Via Marzolo 1, Padova 35131, Italy
| | - J. Fraser Stoddart
- Department of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208, United States
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