653 results on '"*ROTAXANES"'
Search Results
2. Syntheses of three-dimensional catenanes under kinetic control.
- Author
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Wu Y, Guo QH, Qiu Y, Weber JA, Young RM, Bancroft L, Jiao Y, Chen H, Song B, Liu W, Feng Y, Zhao X, Li X, Zhang L, Chen XY, Li H, Wasielewski MR, and Stoddart JF
- Subjects
- Kinetics, Catenanes chemistry, Rotaxanes chemistry
- Abstract
Although catenanes comprising two ring-shaped components can be made in large quantities by templation, the preparation of three-dimensional (3D) catenanes with cage-shaped components is still in its infancy. Here, we report the design and syntheses of two 3D catenanes by a sequence of SN2 reactions in one pot. The resulting triply mechanically interlocked molecules were fully characterized in both the solution and solid states. Mechanistic studies have revealed that a suit[3]ane, which contains a threefold symmetric cage component as the suit and a tribromide component as the body, is formed at elevated temperatures. This suit[3]ane was identified as the key reactive intermediate for the selective formation of the two 3D catenanes which do not represent thermodynamic minima. We foresee a future in which this particular synthetic strategy guides the rational design and production of mechanically interlocked molecules under kinetic control.
- Published
- 2022
- Full Text
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3. Towards polyyne rotaxanes and catenanes
- Author
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Patrick, Connor and Anderson, Harry Laurence
- Subjects
Cyclocarbons ,Supramolecular chemistry ,Catenanes ,Rotaxanes ,Chemistry, Organic ,Polyynes - Abstract
This thesis summarises attempts towards polyyne [n]rotaxanes and cyclocarbon [n]catenanes. Carbon allotropes built purely from sp carbon atoms have long fascinated chemists but have yet to be isolated or characterised due to their high reactivity. This thesis documents work towards isolating both linear and cyclic sp carbon chains. Chapter 1 reviews the history of carbon allotropes, focussing on cyclic and linear forms of sp carbon. Synthetic strategies towards preparing acetylene-rich molecules, rotaxanes and catenanes are discussed. Chapter 2 discusses development of a novel masked alkyne equivalent (MAE) with intrinsic metal binding abilities. A simple masked triyne can be synthesised in only three steps, but photochemical unmasking of this group could not be realised due to a competing dimerisation process. Chapter 3 details new strategies for synthesising polyyne [3]rotaxanes with two macrocycles on the same polyyne thread. An active metal template route using dicobalt-masked precursors was developed to prepare two polyyne [3]rotaxanes. The thermal stabilities of the two rotaxanes were evaluated relative to the naked polyyne dumbbell and were found to be significantly more stable in decalin at 80 °C. Chapter 4 presents a novel approach to cyclocarbon [n]catenanes and polyyne [n]rotaxanes. The coupling of a [2]rotaxane bearing two temporary bulky MAE stoppers provides access to precursors of cyclocarbon [n]catenanes and polyyne [n]rotaxanes. Early unmasking experiments have successfully afforded a polyyne bearing 24 contiguous acetylene units and indicate that larger polyynes should be viable using this route. Chapter 5 summarises.
- Published
- 2022
4. Synthesizing [2]Rotaxanes and [2]Catenanes through Na(+)-Templated Clipping of Macrocycles around Oligo(ethylene glycol) Units.
- Author
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Wu YW, Chen PN, Chang CF, Lai CC, and Chiu SH
- Subjects
- Catenanes chemistry, Ethylene Glycol chemistry, Ions, Magnetic Resonance Spectroscopy, Molecular Structure, Rotaxanes chemical synthesis, Rotaxanes chemistry, Catenanes chemical synthesis, Macrocyclic Compounds chemistry, Sodium chemistry
- Abstract
Di-, tri-, and tetra(ethylene glycol) units in both dumbbell-shaped and macrocyclic molecules can be used as primary recognition units for the clipping of macrocycles in the presence of templating Na(+) ions to form corresponding [2]rotaxanes and [2]catenanes. One such tri(ethylene glycol)-containing [2]catenane behaves as a Na(+) ion-controllable molecular switch.
- Published
- 2015
- Full Text
- View/download PDF
5. Construction of photoswitchable rotaxanes and catenanes containing dithienylethene fragments.
- Author
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Li Z, Han X, Chen H, Wu D, Hu F, Liu SH, and Yin J
- Subjects
- Imines chemistry, Isomerism, Mechanical Phenomena, Models, Molecular, Molecular Conformation, Alkenes chemistry, Catenanes chemistry, Photochemical Processes, Rotaxanes chemistry
- Abstract
Mechanically interlocked structures such as rotaxanes and catenanes provide a novel backbone for constructing functional materials with unique structural characteristics. In this study, we have designed and synthesized a series of photoswitchable rotaxanes and catenanes containing photochromic dithienylethene fragments using a template-directed clipping approach based on dynamic imine chemistry. Their structures have been confirmed using NMR, mass spectrometry and elemental analysis. Investigations into their photoisomerization properties indicated that these dithienylethene-based mechanically interlocked molecules have good reversibility and excellent fatigue resistance upon irradiation with UV or visible light. Interestingly, the mechanically interlocked molecules containing two dithienylethene backbones display around a 2-fold increase in the molar absorption coefficient compared with that of the mono dithienylethene derivative. Furthermore, the introduction of the fluorophore pyrene in the dithienylethene component facilitates these molecules to serve as fluorescent switches.
- Published
- 2015
- Full Text
- View/download PDF
6. Novel porphyrin-fullerene assemblies: from rotaxanes to catenanes.
- Author
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Schuster DI, Li K, Guldi DM, and Ramey J
- Subjects
- Models, Molecular, Molecular Structure, Oxidation-Reduction, Photochemistry, Rotaxanes chemical synthesis, Catenanes chemical synthesis, Fullerenes chemistry, Porphyrins chemistry, Rotaxanes chemistry
- Abstract
[reaction: see text] Titration of porphyrin-fullerene rotaxanes with DABCO or 4,4'-bipyridine led to photo- and redoxactive catenanic architectures, which upon photoexcitation undergo a sequence of short-range energy and electron transfer events to give a long-lived charge-separated radical-pair state.
- Published
- 2004
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7. Alternative demetalation method for Cu(I)-phenanthroline-based catenanes and rotaxanes.
- Author
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Megiatto JD Jr and Schuster DI
- Subjects
- Kinetics, Molecular Structure, Catenanes chemistry, Phenanthrolines chemistry, Rotaxanes chemistry
- Abstract
A new and less hazardous procedure for demetalation of Cu(I)-phenanthroline-based interlocked molecules, using aqueous NH(4)OH rather than toxic KCN, has been developed. The conditions are compatible with materials containing nucleophile-sensitive appended groups such as C(60), and coordinating moieties such as zinc(II)-porphyrins.
- Published
- 2011
- Full Text
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8. Design, assembly, characterization, and operation of double-stranded interlocked DNA nanostructures.
- Author
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Valero J, Centola M, Ma Y, Škugor M, Yu Z, Haydell MW, Keppner D, and Famulok M
- Subjects
- DNA chemical synthesis, Light, Microscopy, Atomic Force, Catenanes chemistry, DNA chemistry, Nanostructures chemistry, Nanotechnology methods, Nucleic Acid Hybridization methods, Rotaxanes chemistry
- Abstract
Mechanically interlocked DNA nanostructures are useful as flexible entities for operating DNA-based nanomachines. Interlocked structures made of double-stranded (ds) DNA components can be constructed by irreversibly threading them through one another to mechanically link them. The interlocked components thus remain bound to one another while still permitting large-amplitude motion about the mechanical bond. The construction of interlocked dsDNA architectures is challenging because it usually involves the synthesis and modification of small dsDNA nanocircles of various sizes, dependent on intrinsically curved DNA. Here we describe the design, generation, purification, and characterization of interlocked dsDNA structures such as catenanes, rotaxanes, and daisy-chain rotaxanes (DCRs). Their construction requires precise control of threading and hybridization of the interlocking components at each step during the assembly process. The protocol details the characterization of these nanostructures with gel electrophoresis and atomic force microscopy (AFM), including acquisition of high-resolution AFM images obtained in intermittent contact mode in liquid. Additional functionality can be conferred on the DNA architectures by incorporating proteins, molecular switches such as photo-switchable azobenzene derivatives, or fluorophores for studying their mechanical behavior by fluorescence quenching or fluorescent resonance energy transfer experiments. These modified interlocked DNA architectures provide access to more complex mechanical devices and nanomachines that can perform a variety of desired functions and operations. The assembly of catenanes can be completed in 2 d, and that of rotaxanes in 3 d. Addition of azobenzene functionality, fluorophores, anchor groups, or the site-specific linkage of proteins to the nanostructure can extend the time line.
- Published
- 2019
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9. A [2]rota[2]catenane, constructed from a pillar[5]arene-crown ether fused double-cavity macrocycle: synthesis and structural characterization.
- Author
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Hu WB, Hu WJ, Zhao XL, Liu YA, Li JS, Jiang B, and Wen K
- Subjects
- Calixarenes, Catenanes chemistry, Molecular Structure, Rotaxanes chemistry, Catenanes chemical synthesis, Crown Ethers chemistry, Quaternary Ammonium Compounds chemistry, Rotaxanes chemical synthesis
- Abstract
A topologically novel [2]rota[2]catenane containing both a pillar[5]arene-imidazolium based [2]rotaxane subunit and a crown ether-tetracationic cyclophane based [2]catenane one was designed and constructed. The structure of the [2]rota[2]catenane was thoroughly characterized by NMR spectra, MS spectrometry and single crystal X-ray diffraction analysis.
- Published
- 2015
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10. Interlocked systems in nanomedicine.
- Author
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Ornelas-Megiatto C, Becher TB, and Megiatto JD Jr
- Subjects
- Animals, Antineoplastic Agents chemistry, Antineoplastic Agents pharmacology, Catenanes metabolism, Dendrimers chemical synthesis, Dendrimers therapeutic use, Gene Transfer Techniques, Humans, Hydrogels chemistry, Hydrogels therapeutic use, Liposomes chemistry, Liposomes therapeutic use, Mice, Nanomedicine instrumentation, Nanoparticles chemistry, Nanoparticles therapeutic use, Neoplasms pathology, Neoplasms therapy, Regeneration, Rotaxanes metabolism, Theranostic Nanomedicine methods, Catenanes chemistry, Diagnostic Imaging methods, Drug Delivery Systems methods, Nanomedicine methods, Rotaxanes chemistry
- Abstract
The concept of Nanomedicine emerged along with the new millennium, and it is expected to provide solutions to some of modern medicine's unsolved problems. Nanomedicine offers new hopes in several critical areas such as cancer treatment, viral and bacterial infections, medical imaging, tissue regeneration, and theranostics. To explore all these applications, a wide variety of nanomaterials have been developed which include liposomes, dendrimers, nanohydrogels and polymeric, metallic and inorganic nanoparticles. Recently, interlocked systems, namely rotaxanes and catenanes, have been incorporated into some of these chemical platforms in an attempt to improve their performance. This review focus on the nanomedicine applications of nanomaterials containing interlocked structures. The introduction gives an overview on the significance of interdisciplinary science in the progress of the nanomedicine field, and it explains the evolution of interlocked molecules until their application in nanomedicine. The following sections are organized by the type of interlocked structure, and it comprises details of the in vitro and/or in vivo experiments involving each material: rotaxanes as imaging agents, rotaxanes as cytotoxic agents, rotaxanes as peptide transporters, mechanized silica nanoparticles as stimuli responsive drug delivery systems, and polyrotaxanes as drug and gene delivery systems.
- Published
- 2015
- Full Text
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11. [2]Pseudorotaxanes and [2]catenanes constructed by oxacalixcrowns/viologen molecular recognition motifs.
- Author
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Liu H, Li XY, Zhao XL, Liu YA, Li JS, Jiang B, and Wen K
- Subjects
- Catenanes chemistry, Molecular Structure, Paraquat chemistry, Protein Structure, Tertiary, Rotaxanes chemistry, Catenanes chemical synthesis, Rotaxanes chemical synthesis, Viologens chemistry
- Abstract
Oxacalix[2]arene[2]pyrazine and functional polyether derived oxacalixcrown-6, -7, and -8 were synthesized, and their host-guest complexation with paraquat to form [2]pseudorotaxanes was studied. The [2]pseudorotaxanes were then successfully used in the construction of two oxacalixcrown-tetracationic cyclophane [CBPQT(4+)] based [2]catenanes.
- Published
- 2014
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12. Synthesis of rotacatenanes by the combination of Cu-mediated threading reaction and the template method: the dual role of one ligand.
- Author
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Hayashi R, Wakatsuki K, Yamasaki R, Mutoh Y, Kasama T, and Saito S
- Subjects
- Catenanes chemistry, Ligands, Rotaxanes chemistry, Catenanes chemical synthesis, Copper chemistry, Macrocyclic Compounds chemistry, Phenanthrolines chemistry, Rotaxanes chemical synthesis
- Abstract
Rotacatenanes were synthesized by the catalytic reaction using a macrocyclic phenanthroline-CuI complex followed by the installation of another ring by the template method. In this approach, the size of the ring component of the rotaxane turns out to be a very important factor for the synthesis of rotacatenanes.
- Published
- 2014
- Full Text
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13. Theoretical design for a light-driven molecular motor based on rotaxanes
- Author
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Sebastian, K. L.
- Published
- 2004
14. Molecular entanglement can strongly increase basicity.
- Author
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Capocasa, Giorgio, Frateloreto, Federico, Valentini, Matteo, and Di Stefano, Stefano
- Subjects
BASICITY ,PROTON affinity ,INORGANIC compounds ,CHEMICAL properties ,CATENANES ,ROTAXANES - Abstract
Brønsted basicity is a fundamental chemical property featured by several kinds of inorganic and organic compounds. In this Review, we treat a particularly high basicity resulting from the mechanical entanglement involving two or more molecular subunits in catenanes and rotaxanes. Such entanglement allows a number of basic sites to be in close proximity with each other, highly increasing the proton affinity in comparison with the corresponding, non-entangled counterparts up to obtain superbases, properly defined as mechanically interlocked superbases. In the following pages, the development of this kind of superbases will be described with a historical perusal, starting from the initial, serendipitous findings up to the most recent reports where the strong basic property of entangled molecular units is the object of a rational design. Brønsted basicity can be greatly enhanced by the mechanical entanglement of two or more interlocked molecular subunits within catenanes and rotaxanes. Here, the authors discuss the development of such mechanically interlocked superbases, and outline challenges and opportunities for future directions of research. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
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15. A High‐Yielding Active Template Click Reaction (AT−CuAAC) for the Synthesis of Mechanically Interlocked Nanohoops.
- Author
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May, James H., Fehr, Julia M., Lorenz, Jacob C., Zakharov, Lev N., and Jasti, Ramesh
- Subjects
- *
CARBON nanotubes , *ROTAXANES , *CATENANES , *NANOSCIENCE , *MOIETIES (Chemistry) , *RING formation (Chemistry) - Abstract
Mechanically interlocked molecules (MIMs) represent an exciting yet underexplored area of research in the context of carbon nanoscience. Recently, work from our group and others has shown that small carbon nanotube fragments—[n]cycloparaphenylenes ([n]CPPs) and related nanohoop macrocycles—may be integrated into mechanically interlocked architectures by leveraging supramolecular interactions, covalent tethers, or metal‐ion templates. Still, available synthetic methods are typically difficult and low yielding, and general methods that allow for the creation of a wide variety of these structures are limited. Here we report an efficient route to interlocked nanohoop structures via the active template Cu‐catalyzed azide‐alkyne cycloaddition (AT−CuAAC) reaction. With the appropriate choice of substituents, a macrocyclic precursor to 2,2′‐bipyridyl embedded [9]CPP (bipy[9]CPP) participates in the AT−CuAAC reaction to provide [2]rotaxanes in near‐quantitative yield, which can then be converted into the fully π‐conjugated catenane structures. Through this approach, two nanohoop[2]catenanes are synthesized which consist of a bipy[9]CPP catenated with either Tz[10]CPP or Tz[12]CPP (where Tz denotes a 1,2,3‐triazole moiety replacing one phenylene ring in the [n]CPP backbone). [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
16. Anion-templated assembly of interpenetrated and interlocked structures.
- Author
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Beer PD, Sambrook MR, and Curiel D
- Subjects
- Catenanes chemistry, Guanidine chemical synthesis, Guanidine chemistry, Imidazoles chemical synthesis, Imidazoles chemistry, Models, Molecular, Pyridinium Compounds chemical synthesis, Pyridinium Compounds chemistry, Rhenium chemistry, Rotaxanes chemistry, Anions chemistry, Catenanes chemical synthesis, Rotaxanes chemical synthesis
- Abstract
The rational development of a general anion templation strategy for the construction of a variety of interpenetrated and interlocked molecular structures based upon the coupling of anion recognition with ion-pairing is described. The success of this anion templation methodology is demonstrated with the halide anion directed assembly of a series of novel [2]pseudorotaxanes containing pyridinium, pyridinium nicotinamide, imidazolium, benzimidazolium and guanidinium threading components and anion binding macrocyclic ligands. Interlocked [2]rotaxane and [2]catenane molecular structures are also synthesised using this anion templation protocol. These interlocked structures feature unique topologically defined hydrogen bond donating binding domains that exhibit a high degree of selectivity for chloride, the templating anion. A series of rhenium(I) bipyridyl containing [2]pseudorotaxane assemblies and a [2]rotaxane further highlight the potential this strategic anion templation approach has in future chemical sensor design and fabrication.
- Published
- 2006
- Full Text
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17. A highly efficient approach to [4]pseudocatenanes by threefold metathesis reactions of a triptycene-based tris[2]pseudorotaxane.
- Author
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Zhu XZ and Chen CF
- Subjects
- Catenanes chemistry, Crystallography, X-Ray, Magnetic Resonance Spectroscopy methods, Models, Molecular, Molecular Structure, Rotaxanes chemical synthesis, Catenanes chemical synthesis, Rotaxanes chemistry
- Abstract
A triptycene-based homotritopic host was designed and synthesized. Assembly of the host with a bisbenzylammonium salt containing terminal double bonds resulted in a tris[2]pseudorotaxane, which further performed the threefold metathesis reaction and then hydrogenation to give a [4]pseudocatenane in high yield. The [4]pseudocatenane exhibited a novel topological structure with high symmetry, which was confirmed by the spectral data and X-ray analysis.
- Published
- 2005
- Full Text
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18. Heteroditopic Rotaxanes and Catenanes for Ion Pair Recognition.
- Author
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Nicholson, Steven J., Barlow, Sean R., and Evans, Nicholas H.
- Subjects
- *
ION pairs , *CATENANES , *ROTAXANES - Abstract
A review of heteroditopic interlocked molecules and their application as receptors for simple inorganic ion pair species. The review details the design and ion recognition properties of the rotaxane and catenane receptors, as well as highlighting some of the experimental challenges; hence, it provides insight into possible future avenues of research in this youthful field. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
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19. Lanthanide-Containing Rotaxanes, Catenanes, and Knots.
- Author
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Evans, Nicholas H.
- Subjects
- *
CATENANES , *ROTAXANES , *COORDINATE covalent bond , *RARE earth metals , *LUMINESCENCE - Abstract
The valuable luminescence, magnetic, and catalytic properties of lanthanide cations are beginning to be exploited in conjunction with structurally exotic mechanically interlocked molecules (MIMs) such as rotaxanes, catenanes and knots. This Minireview provides an account of this rapidly developing research area commencing with the use of lanthanides in extended MIM-containing frameworks. Then, attention turns to discrete lanthanide-containing pseudorotaxanes, followed by fully interlocked rotaxanes, catenanes and knots – where lanthanides have not only been incorporated into MIM architectures but have also been used to template formation of the interlocked structure. Particular focus is paid to examples where the lanthanide MIMs have been put to useful applications, in what is still a relatively youthful avenue of research in both lanthanide coordination chemistry and the chemistry of mechanically interlocked molecules. [ABSTRACT FROM AUTHOR]
- Published
- 2020
- Full Text
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20. Recent Advances in the Synthesis and Functions of Reconfigurable Interlocked DNA Nanostructures.
- Author
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Lu CH, Cecconello A, and Willner I
- Subjects
- Chemistry Techniques, Synthetic, DNA chemical synthesis, DNA, Circular, Fluorescent Dyes chemistry, Rotaxanes chemistry, Catenanes chemistry, DNA chemistry, Nanostructures chemistry, Nanotechnology methods
- Abstract
Interlocked circular DNA nanostructures, e.g., catenanes or rotaxanes, provide functional materials within the area of DNA nanotechnology. Specifically, the triggered reversible reconfiguration of the catenane or rotaxane structures provides a means to yield new DNA switches and to use them as dynamic scaffolds for controlling chemical functions and positioning functional cargoes. The synthesis of two-ring catenanes and their switchable reconfiguration by pH, metal ions, or fuel/anti-fuel stimuli are presented, and the functions of these systems, as pendulum or rotor devices or as switchable catalysts, are described. Also, the synthesis of three-, five-, and seven-ring catenanes is presented, and their switchable reconfiguration using fuel/anti-fuel strands is addressed. Implementation of the dynamically reconfigured catenane structures for the programmed organization of Au nanoparticle (NP) assemblies, which allows the plasmonic control of the fluorescence properties of Au NP/fluorophore loads associated with the scaffold, and for the operation of logic gates is discussed. Interlocked DNA rotaxanes and their different synthetic approaches are presented, and their switchable reconfiguration by means of fuel/anti-fuel strands or photonic stimuli is described. Specifically, the use of the rotaxane as a scaffold to organize Au NP assemblies, and the control of the fluorescence properties with Au NP/fluorophore hybrids loaded on the rotaxane scaffold, are introduced. The future prospectives and challenges in the field of interlocked DNA nanostructures and the possible applications are discussed.
- Published
- 2016
- Full Text
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21. Synthesis of linear [5]catenanes via olefin metathesis dimerization of pseudorotaxanes composed of a [2]catenane and a secondary ammonium salt.
- Author
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Iwamoto H, Tafuku S, Sato Y, Takizawa W, Katagiri W, Tayama E, Hasegawa E, Fukazawa Y, and Haino T
- Subjects
- Catalysis, Dimerization, Molecular Structure, Proton Magnetic Resonance Spectroscopy, Alkenes chemistry, Ammonium Compounds chemistry, Catenanes chemical synthesis, Rotaxanes chemistry
- Abstract
[5]Catenanes were synthesized by olefin metathesis dimerization. The reaction of pseudorotaxanes, which were derived from a [2]catenane and one equivalent of an ammonium salt bearing two terminal olefins in dichloromethane, with a catalytic amount of Grubbs catalyst afforded linear [5]catenanes in 12% yield. Intermolecular and intramolecular olefin metathesis reactions were controlled by the length of the alkyl chain of the ammonium salts.
- Published
- 2016
- Full Text
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22. Pioneering Work on Catenanes, Rotaxanes, and a Knotane in the University of Freiburg 1958–1988.
- Author
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Brückner, Reinhard
- Subjects
- *
CATENANES , *ROTAXANES , *NOBEL Prize in Chemistry , *NOBEL Prizes , *ISOMERISM - Abstract
Research at the University of Freiburg is summarized which aimed at realizing catenanes, rotaxanes, and a molecular knot from 61–62 until 41 years ago. Taking a fresh view at ansa‐compounds – distinct from those in which he had been interested for other reasons before – Arthur Lüttringhaus began to tackle syntheses of catenanes in 1957. The first isolation of a pure catenane (37) succeeded in 1964 jointly with Gottfried Schill. Most of the progress made in the sequel was due to Schill alone or achieved under his direction; in addition, a few follow‐up studies were published without Schill or Lüttringhaus being their authors. The major feats of these endeavors were the syntheses of the following molecules: (1) the first catenanes (38 – de‐acetyl‐41, 74) without a ring in any constituent (this feature makes them unique till today; the catenane 74 holds the additional record of being the only all‐hydrocarbon catenane till now); the first [3]catenanes at all (obtained as a mixture of constitutional isomers C2v‐97 and C2h‐97); the first [3]catenanes exhibiting topological isomerism (89, iso‐89, and neo‐iso‐89); the rotaxanes 70 [which had the design peculiarity of being convertible into a catenane (74)], 113 (Schill's #1‐rotaxane), and 115; the pre‐knotane rac‐dia‐iso‐123 [provided it was obtained and not (only) its topological isomer dia‐iso‐123]. – For due perspectives, pertinent studies of third parties are included, too: 1) Wasserman's reports on the isolation of the catenane 8 are analyzed in great detail; the conclusion is that the identity of 8 was never established. 2) Schill's oscillating rotaxane 70 from 1988, which is subject to a reversible and non‐degenerate ring migration (→ iso‐70), is supplemented by Stoddart's much faster oscillating rotaxane 71 from 1991, which undergoes a reversible and degenerate ring migration (→ 71 instead of → iso‐71) and was dubbed "molecular shuttle". 3) The first [3]catenanes from the groups of Schill (97; 1969), Sauvage (98 and 99; 1985), and Stoddart (100–102; 1991) are juxtaposed. 4) The Harrisons' synthesis of the rotaxane 106 by a most noteworthy solid‐phase approach (1967) is recalled in the context of Schill's synthesis of the rotaxane 113 (1967 or 1969). 5) Attempts at threading α‐cyclodextrin by long‐chain 1,ω‐dithiols (→ 130) and ring‐closing the latter oxidatively for obtaining catenated disulfides failed in Lüttringhaus' 1957/1958 studies; in contrast, Stoddart's threading permethyl‐β‐cyclodextrin (133) by the long‐chain 1,ω‐diamine 132 and ring‐closing the latter by a double condensation with terephthaloyl dichloride was successful by providing 3 % of the catenated bislactame 134 in 1993. The concluding section characterizes the synthetic strategies towards catenanes and rotaxanes developed in Freiburg as "template‐based". This differs from the Nobel Prize Committee's assessment. [ABSTRACT FROM AUTHOR]
- Published
- 2019
- Full Text
- View/download PDF
23. Towards polyyne rotaxanes and catenanes
- Author
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Patrick, CW, Dixon, D, Tykwinksi, R, and Anderson, H
- Subjects
Rotaxanes ,Chemistry, Organic ,Catenanes ,Polyynes ,Cyclocarbons ,Supramolecular chemistry - Abstract
This thesis summarises attempts towards polyyne [n]rotaxanes and cyclocarbon [n]catenanes. Carbon allotropes built purely from sp carbon atoms have long fascinated chemists but have yet to be isolated or characterised due to their high reactivity. This thesis documents work towards isolating both linear and cyclic sp carbon chains. Chapter 1 reviews the history of carbon allotropes, focussing on cyclic and linear forms of sp carbon. Synthetic strategies towards preparing acetylene-rich molecules, rotaxanes and catenanes are discussed. Chapter 2 discusses development of a novel masked alkyne equivalent (MAE) with intrinsic metal binding abilities. A simple masked triyne can be synthesised in only three steps, but photochemical unmasking of this group could not be realised due to a competing dimerisation process. Chapter 3 details new strategies for synthesising polyyne [3]rotaxanes with two macrocycles on the same polyyne thread. An active metal template route using dicobalt-masked precursors was developed to prepare two polyyne [3]rotaxanes. The thermal stabilities of the two rotaxanes were evaluated relative to the naked polyyne dumbbell and were found to be significantly more stable in decalin at 80 °C. Chapter 4 presents a novel approach to cyclocarbon [n]catenanes and polyyne [n]rotaxanes. The coupling of a [2]rotaxane bearing two temporary bulky MAE stoppers provides access to precursors of cyclocarbon [n]catenanes and polyyne [n]rotaxanes. Early unmasking experiments have successfully afforded a polyyne bearing 24 contiguous acetylene units and indicate that larger polyynes should be viable using this route. Chapter 5 summarises
- Published
- 2022
24. Self-assembly of [3]catenanes and a [4]molecular necklace based on a cryptand/paraquat recognition motif.
- Author
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Ye Y, Wang SP, Zhu B, Cook TR, Wu J, Li S, and Stang PJ
- Subjects
- Magnetic Resonance Spectroscopy, Models, Molecular, Molecular Structure, Catenanes chemistry, Crown Ethers chemistry, Ethers, Cyclic chemistry, Paraquat chemistry, Rotaxanes chemistry, Schiff Bases chemistry
- Abstract
Hierarchical self-assembly centered on metallacyclic scaffolds greatly facilitates the construction of mechanically interlocked structures. The formation of two [3]catenanes and one [4]molecular necklace is presented by utilizing the orthogonality of coordination-driven self-assembly and crown ether-based cryptand/paraquat derivative complexation. The threaded [3]catenanes and [4]molecular necklace were fabricated by using ten and nine total molecular components, respectively, from four and three unique species in solution, respectively. In all cases single supramolecular ensembles were obtained, attesting to the high degree of structural complexity made possible via self-assembly approaches.
- Published
- 2015
- Full Text
- View/download PDF
25. Halogen- and hydrogen-bonding catenanes for halide-anion recognition.
- Author
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Gilday LC and Beer PD
- Subjects
- Anions chemistry, Catenanes chemical synthesis, Halogens chemistry, Hydrogen Bonding, Magnetic Resonance Spectroscopy, Rotaxanes chemical synthesis, Rotaxanes chemistry, Catenanes chemistry
- Abstract
Halogen-bonding (XB) interactions were exploited in the solution-phase assembly of anion-templated pseudorotaxanes between an isophthalamide-containing macrocycle and bromo- or iodo-functionalised pyridinium threading components. (1)H NMR spectroscopic titration investigations demonstrated that such XB interpenetrated assemblies are more stable than analogous hydrogen bonding (HB) pseudorotaxanes. The stability of the anion-templated halogen-bonded pseudorotaxane architectures was exploited in the preparation of new halogen-bonding interlocked catenane species through a Grubbs' ring-closing metathesis (RCM) clipping methodology. The catenanes' anion recognition properties in the competitive CDCl(3)/CD(3) OD 1:1 solvent mixture revealed selectivity for the heavier halides iodide and bromide over chloride and acetate., (© 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)
- Published
- 2014
- Full Text
- View/download PDF
26. From construction to application of a new generation of interlocked molecules composed of heteroditopic wheels.
- Author
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Nandi, Mandira, Bej, Somnath, Jana, Tarun, and Ghosh, Pradyut
- Subjects
- *
ROTAXANES , *MOLECULES , *WHEELS , *MEDICAL sciences , *PHENANTHROLINE , *CATENANES , *DIARYLETHENE - 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. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
27. Ground-state kinetics of bistable redox-active donor-acceptor mechanically interlocked molecules.
- Author
-
Fahrenbach AC, Bruns CJ, Li H, Trabolsi A, Coskun A, and Stoddart JF
- Subjects
- Kinetics, Molecular Conformation, Oxidation-Reduction, Static Electricity, Stereoisomerism, Catenanes chemistry, Rotaxanes chemistry
- Abstract
The ability to design and confer control over the kinetics of theprocesses involved in the mechanisms of artificial molecular machines is at the heart of the challenge to create ones that can carry out useful work on their environment, just as Nature is wont to do. As one of the more promising forerunners of prototypical artificial molecular machines, chemists have developed bistable redox-active donor-acceptor mechanically interlocked molecules (MIMs) over the past couple of decades. These bistable MIMs generally come in the form of [2]rotaxanes, molecular compounds that constitute a ring mechanically interlocked around a dumbbell-shaped component, or [2]catenanes, which are composed of two mechanically interlocked rings. As a result of their interlocked nature, bistable MIMs possess the inherent propensity to express controllable intramolecular, large-amplitude, and reversible motions in response to redox stimuli. In this Account, we rationalize the kinetic behavior in the ground state for a large assortment of these types of bistable MIMs, including both rotaxanes and catenanes. These structures have proven useful in a variety of applications ranging from drug delivery to molecular electronic devices. These bistable donor-acceptor MIMs can switch between two different isomeric states. The favored isomer, known as the ground-state co-conformation (GSCC) is in equilibrium with the less favored metastable state co-conformation (MSCC). The forward (kf) and backward (kb) rate constants associated with this ground-state equilibrium are intimately connected to each other through the ground-state distribution constant, KGS. Knowing the rate constants that govern the kinetics and bring about the equilibration between the MSCC and GSCC, allows researchers to understand the operation of these bistable MIMs in a device setting and apply them toward the construction of artificial molecular machines. The three biggest influences on the ground-state rate constants arise from (i) ground-state effects, the energy required to breakup the noncovalent bonding interactions that stabilize either the GSCC or MSCC, (ii) spacer effects, where the structures overcome additional barriers, either steric or electrostatic or both, en route from one co-conformation to the other, and (iii) the physical environment of the bistable MIMs. By managing all three of these effects, chemists can vary these rate constants over many orders of magnitude. We also discuss progress toward achieving mechanostereoselective motion, a key principle in the design and realization of artificial molecular machines capable of doing work at the molecular level, by the strategic implementation of free energy barriers to intramolecular motion.
- Published
- 2014
- Full Text
- View/download PDF
28. Chiral Catenanes and Rotaxanes: Fundamentals and Emerging Applications.
- Author
-
Evans, Nicholas H.
- Subjects
- *
CATENANES , *ROTAXANES , *CHIRALITY , *MOLECULAR machinery (Technology) , *MACROCYCLIC compounds - Abstract
Abstract: Molecular chirality provides a key challenge in host–guest recognition and other related chemical applications such as asymmetric catalysis. For a molecule to act as an efficient enantioselective receptor, it requires multi‐point interactions between host and chiral guest, which may be achieved by an appropriate chiral 3D scaffold. As a consequence of their interlocked structure, catenanes and rotaxanes may present such a 3D scaffold, and can be chiral by inclusion of a classical chiral element and/or as a consequence of the mechanical bond. This Minireview presents illustrative examples of chiral [2]catenanes and [2]rotaxanes, and discusses where these molecules have been used in chemical applications such as chiral host–guest recognition and asymmetric catalysis. [ABSTRACT FROM AUTHOR]
- Published
- 2018
- Full Text
- View/download PDF
29. Chiral Mechanically Interlocked Molecules - Applications of Rotaxanes, Catenanes and Molecular Knots in Stereoselective Chemosensing and Catalysis.
- Author
-
Pairault, Noel and Niemeyer, Jochen
- Subjects
- *
ROTAXANES , *CATENANES , *STEREOSELECTIVE reactions - Abstract
Interlocked molecules, such as rotaxanes, catenanes, and molecular knots, offer conceptually new possibilities for the generation of chiral chemosensors and catalysts. Due to the presence of the mechanical or topological bond, interlocked molecules can be used to design functional systems with unprecedented features, such as switchability and deep binding cavities. In addition, classical elements of chirality can be supplemented with mechanical or topological chirality, which have so far only scarcely been employed as sources of chirality for stereoselective applications. This minireview discusses recent examples in this emerging area, showing that the application of chiral interlocked molecules in sensing and catalysis offers many fascinating opportunities for future research. 1 Introduction 2 Interlocked Molecules with Chiral Subcomponents 2.1 Point Chirality 2.2 Axial Chirality 3 Mechanically Chiral Interlocked Molecules 4 Topologically Chiral Interlocked Molecules 5 Outlook [ABSTRACT FROM AUTHOR]
- Published
- 2018
- Full Text
- View/download PDF
30. Chemical peristalsis.
- Author
-
Astumian RD
- Subjects
- Catenanes chemistry, Macromolecular Substances, Nanotechnology, Rotaxanes chemistry, Rotaxanes metabolism, Thermodynamics, Catenanes metabolism, Models, Theoretical, Molecular Motor Proteins metabolism
- Abstract
Molecules that emulate in part the remarkable capabilities of protein motors were recently chemically synthesized. A promising approach is based on physically interlocked macromolecular complexes such as rotaxanes and catenanes. Using the latter, Leigh et al. [Leigh, D. A., Wong, J. K. Y., Dehez, F. & Zerbetto, F. (2003) Nature 424, 174-179] constructed a molecular rotor in which two small rings are induced by pulses of light to move unidirectionally around a third, larger ring. The mechanism is similar to that by which a peristaltic pump operates. Unlike macroscopic peristalsis, however, in which a traveling wave forces material through a series of one-way valves, the chemical peristaltic mechanism does not directly cause the small rings to move but only alters the energetics, with the motion itself arising by thermal activation over energy barriers. Engines operating by this mechanism are "Brownian" motors. Here we describe a minimal two-state mechanism for a catenane-based molecular motor. Although fluctuations caused by equilibrium processes cannot drive directed motion, nonequilibrium fluctuations, whether generated externally or by a far-from-equilibrium chemical reaction, can drive rotation even against an external torque. We discuss a possible architecture for input and output of information and energy between the motor and its environment and give a simple expression for the maximum thermodynamic efficiency. The proposed Brownian motor mechanism is consistent with the high efficiency observed by Yasuda et al. [Yasuda, Y., Noji, H., Kinoshita, K. & Yoshida, M. (1998) Cell 93, 1117-1124] for the F(1)-ATP synthase operating as an ATP-powered molecular rotor.
- Published
- 2005
- Full Text
- View/download PDF
31. Catenane and Rotaxane Synthesis from Cucurbit[6]uril‐Mediated Azide‐Alkyne Cycloaddition.
- Author
-
Tse, Yuen Cheong and Au‐Yeung, Ho Yu
- Subjects
RING formation (Chemistry) ,COVALENT bonds ,CATENANES ,ROTAXANES ,CLICK chemistry ,MOLECULES - Abstract
The chemistry of mechanically interlocked molecules (MIMs) such as catenane and rotaxane is full of new opportunities for the presence of a mechanical bond, and the efficient synthesis of these molecules is therefore of fundamental importance in realizing their unique properties and functions. While many different types of preorganizing interactions and covalent bond formation strategies have been exploited in MIMs synthesis, the use of cucurbit[6]uril (CB[6]) in simultaneously templating macrocycle interlocking and catalyzing the covalent formation of the interlocked components is particularly advantageous in accessing high‐order catenanes and rotaxanes. In this review, catenane and rotaxane obtained from CB[6]‐catalyzed azide‐alkyne cycloaddition will be discussed, with special emphasis on the synthetic strategies employed for obtaining complex [n]rotaxanes and [n]catenanes, as well as their properties and functions. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
32. Ground-state thermodynamics of bistable redox-active donor-acceptor mechanically interlocked molecules.
- Author
-
Fahrenbach AC, Bruns CJ, Cao D, and Stoddart JF
- Subjects
- Oxidation-Reduction, Catenanes chemistry, Rotaxanes chemistry, Thermodynamics
- Abstract
Fashioned through billions of years of evolution, biological molecular machines, such as ATP synthase, myosin, and kinesin, use the intricate relative motions of their components to drive some of life's most essential processes. Having control over the motions in molecules is imperative for life to function, and many chemists have designed, synthesized, and investigated artificial molecular systems that also express controllable motions within molecules. Using bistable mechanically interlocked molecules (MIMs), based on donor-acceptor recognition motifs, we have sought to imitate the sophisticated nanoscale machines present in living systems. In this Account, we analyze the thermodynamic characteristics of a series of redox-switchable [2]rotaxanes and [2]catenanes. Control and understanding of the relative intramolecular movements of components in MIMs have been vital in the development of a variety of applications of these compounds ranging from molecular electronic devices to drug delivery systems. These bistable donor-acceptor MIMs undergo redox-activated switching between two isomeric states. Under ambient conditions, the dominant translational isomer, the ground-state coconformation (GSCC), is in equilibrium with the less favored translational isomer, the metastable-state coconformation (MSCC). By manipulating the redox state of the recognition site associated with the GSCC, we can stimulate the relative movements of the components in these bistable MIMs. The thermodynamic parameters of model host-guest complexes provide a good starting point to rationalize the ratio of GSCC to MSCC at equilibrium. The bistable [2]rotaxanes show a strong correlation between the relative free energies of model complexes and the ground-state distribution constants (K(GS)). This relationship does not always hold for bistable [2]catenanes, most likely because of the additional steric and electronic constraints present when the two rings are mechanically interlocked with each other. Measuring the ground-state distribution constants of bistable MIMs presents its own set of challenges. While it is possible, in principle, to determine these constants using NMR and UV-vis spectroscopies, these methods lack the sensitivity to permit the determination of ratios of translational isomers greater than 10:1 with sufficient accuracy and precision. A simple application of the Nernst equation, in combination with variable scan-rate cyclic voltammetry, however, allows the direct measurement of ground-state distribution constants across a wide range (K(GS) = 10-10(4)) of values.
- Published
- 2012
- Full Text
- View/download PDF
33. The synthesis and properties of peptide based [2]rotaxanes
- Author
-
Meurs, Sandra van
- Subjects
547 ,Catenanes - Published
- 2001
34. Thermodynamic forecasting of mechanically interlocked switches.
- Author
-
Olson MA, Braunschweig AB, Ikeda T, Fang L, Trabolsi A, Slawin AM, Khan SI, and Stoddart JF
- Subjects
- Calorimetry, Crystallography, X-Ray, Electrochemistry, Models, Molecular, Molecular Conformation, Paraquat chemistry, Reproducibility of Results, Catenanes chemistry, Mechanical Phenomena, Rotaxanes chemistry, Thermodynamics
- Abstract
Mechanically interlocked molecular (MIM) switches in the form of bistable [2]rotaxanes and [2]catenanes have proven to be--when incorporated in molecular electronic devices (MEDs) and in nanoelectromechanical systems (NEMS)--a realistic and viable alternative to the silicon chip density challenge. Structural modifications and chemical environment can have a large impact on the relaxation thermodynamics of the molecular motions, such as translation and circumrotation in bistable rotaxanes and catenanes responsible for the operation of devices based on MIMs. The effects of structural modifications on the difference in free energy (DeltaG(o)) for the equilibrium processes in switchable MIMs can be predicted by considering, firstly, the interactions present in their precursor pseudorotaxanes. By employing isothermal titration microcalorimetry (ITC) to investigate the thermodynamic parameters governing pseudorotaxane formation for a series of monosubstituted, acceptor host cyclophanes with various donor guests, in conjunction with X-ray crystallographic data, an obvious link between the noncovalent bonding interactions in pseudorotaxanes and MIMs that survive following the formation of the mechanical bond can be identified. It follows that the changes (DeltaDeltaG(o) values) in the difference of free energy during the formation of different pseudorotaxanes can subsequently be extrapolated to predict DeltaG(o) values for the thermodynamics associated with switching in analogous MIM switches, employing the same donor-acceptor recognition components. In this manner, a systematic and predictive thermodynamic approach to designing and tuning switchable MIMs and MIM-based materials has been established. Additionally, these thermodynamic relationships are reminiscent of the long forgotten concept of the 'parachor' as a molecular descriptor with respect to the additivity of physical properties in chemical systems dealing specifically with quantitative structure property-activity relationships (QSPR/QSAR).
- Published
- 2009
- Full Text
- View/download PDF
35. Polypseudorotaxanes via ring-opening metathesis polymerizations of [2]catenanes.
- Author
-
Kang S, Berkshire BM, Xue Z, Gupta M, Layode C, May PA, and Mayer MF
- Subjects
- Molecular Structure, Catenanes chemistry, Polymers chemistry, Rotaxanes chemistry
- Abstract
A bis-phenanthroline [2]catenane copper complex, consisting of one olefinic macrocycle and one nonolefinic macrocycle, underwent an entropy-driven ring-opening olefin metathesis polymerization (ROMP) to provide a polypseudorotaxane. The polymerization featured an average degree of polymerization of ca. 63 wherein the polymer was effectively saturated with threaded macrocycles. Removal of the copper led to near complete release of the macrocycles from the polymer backbone.
- Published
- 2008
- Full Text
- View/download PDF
36. Neutral Donor–acceptor Porphyrin-stoppered [2]Rotaxanes.
- Author
-
Gunter, Maxwell J. and Merican, Zulkifli
- Subjects
- *
ROTAXANES , *CYCLIC compounds , *PORPHYRINS , *MACROCYCLIC compounds , *ACYLATION , *CHEMICAL reactions , *SUPRAMOLECULAR chemistry - Abstract
A series of porphyrin-stoppered [2]rotaxanes incorporating neutral naphthodiimide and dinaphtho-crown ether subunits have been assembled using Pd-catalysed coupling reactions and by acylations of hydroxy and amino functions on the porphyrin stopper units. This establishes the methodology for the production of more complex systems which can be addressed by the porphyrin components. [ABSTRACT FROM AUTHOR]
- Published
- 2005
- Full Text
- View/download PDF
37. Transition Metal-complexed Catenanes and Rotaxanes as Light-driven Molecular Machines Prototypes.
- Author
-
Collin, Jean-Paul and Sauvage, Jean-Pierre
- Subjects
CATENANES ,ROTAXANES ,RUTHENIUM ,POLYCYCLIC compounds ,CYCLIC compounds ,PLATINUM group - Abstract
In the course of the last decade, many dynamic molecular systems, for which the movements are controlled from the outside, have been elaborated. These compounds are generally referred to as "molecular machines." Our group has made and studied catenanes and rotaxanes since the early 80s. An important class of molecular machines is based on these interlocking or threaded ring compounds. Although a "molecular muscle" is briefly discussed in the present review article, we mostly focus on light-driven machines, consisting of ruthenium(II)-complexed rotaxanes or catenanes. The synthetic approach is based on the template effect of an octahedral ruthenium(II) centres. Two 1,10-phenanthroline ligands are incorporated in an axis or in a ring, affording the precursor to the rotaxane or the catenane, respectively. Ru(diimine)
3 2+ complexes display the universally used ³MLCT (metal-to-ligand charge transfer) excited state and, another interesting excited state, the ³LF (ligand field) state, which is strongly dissociative. In the past, the ³LF state has mostly been considered as detrimental and thus, its reactivity has not been frequently utilised. By taking advantage of this latter state, it has been possible to propose a new family of molecular machines, which are set in motion by populating the dissociative ³LF state, thus leading to ligand exchange in the coordination sphere of the ruthenium(II) centre. [ABSTRACT FROM AUTHOR]- Published
- 2005
- Full Text
- View/download PDF
38. Synthesizing [2]Rotaxanes and [2]Catenanes through Na+-Templated Clipping of Macrocycles around Oligo(ethylene glycol) Units.
- Author
-
Yi-Wei Wu, Pei-Nung Chen, Chia-Fong Chang, Chien-Chen Lai, and Sheng-Hsien Chiu
- Subjects
- *
ROTAXANES synthesis , *ETHYLENE glycol , *MACROCYCLIC compounds , *MOLECULAR recognition , *CATENANES , *SODIUM ions , *CHEMICAL templates - Abstract
Di-, tri-, and tetra(ethylene glycol) units in both dumbbell-shaped and macrocyclic molecules can be used as primary recognition units for the clipping of macrocycles in the presence of templating Na+ ions to form corresponding [2]rotaxanes and [2]catenanes. One such tri(ethylene glycol)-containing [2]catenane behaves as a Na+ ion-controllable molecular switch. [ABSTRACT FROM AUTHOR]
- Published
- 2015
- Full Text
- View/download PDF
39. Recent Advances in the Synthesis and Application of Hydrogen Bond Templated Rotaxanes and Catenanes.
- Author
-
Evans, Nicholas H.
- Subjects
HYDROGEN bonding ,HYDROGEN production ,CATENANES ,ROTAXANES ,CELL imaging - Abstract
Alongside the use of metal cations and π–π stacking, hydrogen bonding is one of the major templating interactions used to prepare rotaxanes and catenanes. In this review, a brief summary of key historical milestones will be followed by discussion of developments from over the last decade in both synthetic methodology and application of hydrogen bond templated interlocked molecules. Hydrogen bond templation can allow for rapid access to interlocked molecules in high yields, with select examples having been put to useful purpose, in applications such as organocatalysis and cellular imaging. [ABSTRACT FROM AUTHOR]
- Published
- 2019
- Full Text
- View/download PDF
40. Stimuli-responsive mechanically interlocked molecules constructed from cucurbit[n]uril homologues and derivatives.
- Author
-
Liu, Jing-Xin, Chen, Kai, and Redshaw, Carl
- Subjects
CUCURBITACEAE ,SUPRAMOLECULAR chemistry ,DENDRIMERS ,MOLECULES ,ROTAXANES ,CATENANES - Abstract
Cucurbit[n]uril supramolecular chemistry has developed rapidly since 2001 when different cucurbit[n]uril homologues (Q[n]) were successfully separated in pure form. The combination of Q[n] cavity size and various types of external stimuli has given birth to numerous types of Q[n]-based mechanically interlocked molecules (MIMs), including (pseudo)rotaxanes, catenanes, dendrimers and poly(pseudo)rotaxanes. In this review article, the important advances in the field of Q[n]-based MIMs over the past two decades are highlighted. This review also describes examples of heterowheel (pseudo)rotaxanes and poly(pseudo)rotaxanes involving Q[n]s, and reflects on the opportunities and challenges of constructing Q[n]-based stimuli-responsive MIMs. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
41. Heteroditopic Calix[6]arene Based Intervowen and Interlocked Molecular Devices.
- Author
-
Cera, Gianpiero, Arduini, Arturo, Secchi, Andrea, Credi, Alberto, and Silvi, Serena
- Subjects
- *
SUPRAMOLECULAR chemistry , *ROTAXANES , *FUNCTIONAL groups , *BINDING sites , *CALIXARENES - 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. [ABSTRACT FROM AUTHOR]
- Published
- 2021
- Full Text
- View/download PDF
42. Chemical consequences of mechanical bonding in catenanes and rotaxanes: isomerism, modification, catalysis and molecular machines for synthesis.
- Author
-
Neal, Edward A. and Goldup, Stephen M.
- Subjects
- *
CATENANES , *ROTAXANES , *ISOMERISM , *MOLECULAR machinery (Technology) , *ELECTRONIC equipment , *ORGANIC synthesis - Abstract
Research on mechanically interlocked molecules has advanced substantially over the last five decades. A large proportion of the published work focusses on the synthesis of these challenging targets, and the subsequent control of the relative position of the covalent sub-components, to generate novel molecular devices and machines. In this Feature Article we instead review some of the less discussed consequences of mechanical bonding for the chemical behaviour of catenanes and rotaxanes, and their application in synthesis, including striking recent examples of molecular machines which carry out complex synthetic tasks. [ABSTRACT FROM AUTHOR]
- Published
- 2014
- Full Text
- View/download PDF
43. Peptide-based rotaxanes and catenanes: an emerging class of supramolecular chemistry systems.
- Author
-
Moretto, Alessandro, Crisma, Marco, Formaggio, Fernando, and Toniolo, Claudio
- Subjects
- *
CATENANES , *ROTAXANES , *PEPTIDES , *SUPRAMOLECULAR chemistry , *MACROCYCLIC compounds - Abstract
[2]Rotaxanes are interlocked molecular systems in which the cavity of a macrocycle (wheel) is threaded by a linear compound (axle). The axle is held in place principally by a sterically demanding moiety (stopper) at each end. If the two ends of a rotaxane are covalently linked together, then an assembly of two intertwined macrocycles (termed [2]catenane) is generated. Although rotaxanes and catenanes have been extensively investigated by several research groups, only a limited amount of studies has been devoted to these systems when a peptide molecule characterizes either the axle or the wheel(s) (or both). The purpose of this short conceptual overview is to summarize recent findings on synthetic and naturally occurring peptide-based [2]rotaxanes, [3]rotaxanes, and [2]catenanes and discuss future prospects for the research in this emerging area of supramolecular chemistry. [ABSTRACT FROM AUTHOR]
- Published
- 2012
- Full Text
- View/download PDF
44. Post‐Synthetic Macrocyclization of Rotaxane Building Blocks.
- Author
-
Gauthier, Maxime, Waelès, Philip, and Coutrot, Frédéric
- Subjects
- *
DRUG target , *ROTAXANES , *RING formation (Chemistry) , *SUPRAMOLECULAR chemistry - Abstract
Although not often encountered, cyclic interlocked molecules are appealing molecular targets because of their restrained tridimensional structure which is related to both the cyclic and interlocked shapes. Interlocked molecules such as rotaxane building blocks may be good candidates for post‐synthetic intramolecular cyclization if the preservation of the mechanical bond ensures the interlocked architecture throughout the reaction. This is obviously the case if the modification does not involve the cleavage of either the macrocycle's main chain or the encircled part of the axle. However, among the post‐synthetic reactions, the chemical linkage between two reactive sites belonging to embedded elements of rotaxanes still consists of an underexploited route to interlocked cyclic molecules. This Review lists the rare examples of macrocyclization through chemical connection between reactive sites belonging to a surrounding macrocycle and/or an encircled axle of interlocked rotaxanes. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
45. Rational Design and Cellular Synthesis of Proteins with Unconventional Chemical Topology.
- Author
-
Tianzuo Li, Fan Zhang, Jing Fang, Yajie Liu, and Wen-Bin Zhang
- Subjects
PROTEIN synthesis ,PROTEIN engineering ,TOPOLOGY ,CATENANES ,ROTAXANES - Abstract
Chemical topology refers to the three-dimensional arrangement (i.e., connectivity and spatial relationship) of a molecule's constituent atoms and bonds. The molecular mechanism for translation defines the linear configuration of all nascent proteins. Nontrivial protein topology arises only upon post-translational processing events and often imparts functional benefits such as enhanced stability, making topology a unique dimension for protein engineering. Utilizing the assembly-reaction synergy, our group has developed several methods for the effective and convenient cellular synthesis of a variety of topological proteins, such as lasso proteins, protein rotaxanes, and protein catenanes. The work opens the access to new protein classes and paves the road toward illustrating the topological effects on structure-function relationship of proteins, which lays solid foundation for exploring topological proteins' practical application. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
46. Rotaxanes and pseudorotaxanes with threads containing viologen units.
- Author
-
Deska, Malgorzata, Kozlowska, Jolanta, and Sliwa, Wanda
- Subjects
- *
ROTAXANES , *VIOLOGENS , *CROWN ethers , *CRYPTANDS , *CATENANES , *HYDROGEN bonding - Abstract
In the present review rotaxanes and pseudorotaxanes with threads containing viologen units are described. First the rotaxanes and pseudorotaxanes in which the crown ether serves as a ring are presented, they are followed by rotaxanes and pseudorotaxanes containing the crown-based cryptand as a ring. For the above interlocked species the synthetic approaches and properties, especially those promising for their use in sensors and switches are shown. [ABSTRACT FROM AUTHOR]
- Published
- 2013
47. Palladium-Templated Subcomponent Self-Assembly of Macrocycles, Catenanes, and Rotaxanes.
- Author
-
Browne, Colm, Ronson, Tanya K., and Nitschke, Jonathan R.
- Subjects
- *
CATENANES , *ROTAXANES , *MOLECULAR self-assembly , *CHEMICAL templates , *AMINES - Abstract
The reaction of 2,6-diformylpyridine with diverse amines and PdII ions gave rise to a variety of metallosupramolecular species, in which the PdII ion is observed to template a tridentate bis(imino)pyridine ligand. These species included a mononuclear complex as well as [2+2] and [3+3] macrocycles. The addition of pyridine-containing macrocyclic capping ligands allows for topological complexity to arise, thereby enabling the straightforward preparation of structures that include a [2]catenane, a [2]rotaxane, and a doubly threaded [3]rotaxane. [ABSTRACT FROM AUTHOR]
- Published
- 2014
- Full Text
- View/download PDF
48. Efficient Potassium-lon-Templated Synthesis and Controlled Destruction of [2]Rotaxanes Based on Cascade Complexes.
- Author
-
Tao Hant and Chuan-Feng Chen
- Subjects
- *
TRANSITION metal ions , *ROTAXANES , *CATENANES , *LIGANDS (Chemistry) , *ANTHRAQUINONES , *SUPRAMOLECULAR chemistry - Abstract
The article discusses the formation and usage of transition metal ions in rotaxanes and catenanes. It says that the metal ions have stable interactions with ligands that are used for the efficiency of templated-directed synthesis of several supramolecular architectures and interlocked molecules. It investigates the cascade complex formation between host 1 and anthraquinone. It also presents the synthesis of three potassium-ion-templated rotaxanes as well as its deslipping behaviors.
- Published
- 2008
- Full Text
- View/download PDF
49. Covalently Templated Syntheses of Mechanically Interlocked Molecules.
- Author
-
Cornelissen, Milo D., Pilon, Simone, and van Maarseveen, Jan H.
- Subjects
- *
CATENANES , *ROTAXANES , *MOLECULES , *CARBONATES - Abstract
Mechanically interlocked molecules (MiMs), such as catenanes and rotaxanes, exhibit unique properties due to the mechanical bond which unites their components. The translational and rotational freedom present in these compounds may be harnessed to create stimuli-responsive MiMs, which find potential application as artificial molecular machines. Mechanically interlocked structures such as lasso peptides have also been found in nature, making MiMs promising albeit elusive targets for drug discovery. Although the first syntheses of MiMs were based on covalent strategies, approaches based on non-covalent interactions rose to prominence thereafter and have remained dominant. Non-covalent strategies are generally short and efficient, but do require particular structural motifs which are difficult to alter. In a covalent approach, MiMs can be more easily modified while the components may have increased rotational and translational freedom. Both approaches have complementary merits and combining the unmatched efficiency of non-covalent approaches with the scope of covalent syntheses may open up vast opportunities. In this review, recent covalently templated syntheses of MiMs are discussed to show their complementarity and anticipate future developments in this field. 1 Introduction 2 Tetrahedral Templates 2.1 A Carbonate Template for Non-Rusty Catenanes 2.2 All-Benzene Catenanes on a Silicon Template 2.3 Backfolding from Quaternary Carbon 3 Planar Templates 3.1 Rotaxanes Constructed in a Ring 3.2 Hydrindacene as a Dynamic Covalent Template 3.3 Templating on Tri- and Tetrasubstituted Benzenes 4 Conclusion [ABSTRACT FROM AUTHOR]
- Published
- 2021
- Full Text
- View/download PDF
50. Synthesizing [2]Rotaxanes and [2]Catenanes through Na+-Templated Clipping of Macrocycles around Oligo(ethylene glycol) Units
- Author
-
Chia-Fong Chang, Pei-Nung Chen, Chien-Chen Lai, Yi-Wei Wu, and Sheng-Hsien Chiu
- Subjects
Ions ,Molecular switch ,Ethylene Glycol ,Macrocyclic Compounds ,Magnetic Resonance Spectroscopy ,Molecular Structure ,Rotaxanes ,biology ,Sodium ,Organic Chemistry ,Catenane ,Catenanes ,biology.organism_classification ,Biochemistry ,chemistry.chemical_compound ,chemistry ,Clipping (morphology) ,Polymer chemistry ,Molecule ,Tetra ,Physical and Theoretical Chemistry ,Ethylene glycol - Abstract
Di-, tri-, and tetra(ethylene glycol) units in both dumbbell-shaped and macrocyclic molecules can be used as primary recognition units for the clipping of macrocycles in the presence of templating Na(+) ions to form corresponding [2]rotaxanes and [2]catenanes. One such tri(ethylene glycol)-containing [2]catenane behaves as a Na(+) ion-controllable molecular switch.
- Published
- 2015
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