Amplification of Acetylcholine-Binding Catenanes from Dynamic Combinatorial Libraries

Lam, Ruby T S; Belenguer, Ana M.; Roberts, Susan C.; Naumann, Christoph; Jarrosson, Thibaut; Otto, Sijbren; Sanders, Jeremy K. M.

doi:10.1126/science.1109999

Cited by 290 publications

(199 citation statements)

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“…Investigations of the expression of chiral information during self-organization have led to the development of a remarkable array of structures and functions, 17,19,[56][57][58][59][60] from the sergeantsand-soldiers principle 61,62 to a light-powered rotor. 63,64 The chiral information expressed by the system comprising helicate 1 and its diastereomers allowed us to track separately the reversible ligand-exchange and imine-exchange processes occurring within this mixture of structures.…”

Section: Discussionmentioning

confidence: 99%

Self-Sorting Chiral Subcomponent Rearrangement During Crystallization

et al. 2007

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Abstract:The incorporation of enantiopure 1-amino-2,3-propanediol as a subcomponent into a dicopper double helicate resulted in perfect chiral induction of the helicate's twist. DFT calculations allowed the determination of the helicity of the complex in solution. The same helical induction, in which S amines induced a Λ helical twist, was observed in the solid state by X-ray crystallography. Electronic structure calculations also revealed that the unusual deep green color of this class of complexes was due to a metalto-ligand charge transfer excitation, in which the excited state possesses a valence delocalized Cu2 3+ core. The use of a racemic amine subcomponent resulted in the formation of a dynamic library of six diastereomeric pairs of enantiomers. Surprisingly, this library converted into a single pair of enantiomers during crystallization. We were able to observe this process reverse upon redissolution, as initial ligand exchange was followed by covalent imine metathesis.

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Section: Discussionmentioning

confidence: 99%

Self-Sorting Chiral Subcomponent Rearrangement During Crystallization

et al. 2007

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“…Although other syntheses of trefoil knots have been reported [15][16][17][18][19][20][21][22] (as have composites of trefoil knots 23 and other molecular topologies such as catenanes [24][25][26][27][28] and Borromean links 29 ), higher-order molecular knots remain elusive. Here, we report on the synthesis of a molecular pentafoil knot that combines the use of metal helicates to create crossover points 30 , anion template assembly to form a cyclic array of the correct size [31][32][33] , and the joining of the metal complexes by reversible imine bond formation 34-37 aided by the gauche effect 38 to make the continuous 160-atom-long covalent backbone of the most complex non-DNA molecular knot prepared to date.…”

mentioning

confidence: 99%

A synthetic molecular pentafoil knot

Ayme

Beves

Leigh³

et al. 2011

Nature Chem

388

243

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Knots are being discovered with increasing frequency in both biological and synthetic macromolecules and have been fundamental topological targets for chemical synthesis for the past two decades. Here, we report on the synthesis of the most complex non-DNA molecular knot prepared to date: the self-assembly of five bis-aldehyde and five bis-amine building blocks about five metal cations and one chloride anion to form a 160-atom-loop molecular pentafoil knot (five crossing points). The structure and topology of the knot is established by NMR spectroscopy, mass spectrometry and X-ray crystallography, revealing a symmetrical closed-loop double helicate with the chloride anion held at the centre of the pentafoil knot by ten CH ... Cl -hydrogen bonds. The one-pot self-assembly reaction features an exceptional number of different design elements-some well precedented and others less well known within the context of directing the formation of (supra)molecular species. We anticipate that the strategies and tactics used here can be applied to the rational synthesis of other higher-order interlocked molecular architectures.K nots are important structural features in DNA 1 , are found in some proteins [2][3][4][5] and are thought to play a significant role in the physical properties of both natural and synthetic polymers 6,7 . Although billions of prime knots are known to mathematics 8 , to date the only ones to have succumbed to chemical synthesis using building blocks other than DNA are the topologically trivial unknot (that is, a simple closed loop without any crossing points) and the next simplest knot (featuring three crossing points), the trefoil knot 9,10 . A pentafoil knot-also known as a cinquefoil knot or Solomon's seal knot (the 5 1 knot in Alexander-Briggs notation 11 )-is a torus knot 12 with five crossing points, is inherently chiral, and is the fourth prime knot (following the unknot, trefoil knot and figure-of-eight knot) in terms of number of crossing points and complexity 8,11,12 .Sauvage reported the first molecular knot synthesis 13 , using a linear metal helicate 14 to generate the three crossing points required for a trefoil knot. Although other syntheses of trefoil knots have been reported [15][16][17][18][19][20][21][22] (as have composites of trefoil knots 23 and other molecular topologies such as catenanes [24][25][26][27][28] and Borromean links 29 ), higher-order molecular knots remain elusive. Here, we report on the synthesis of a molecular pentafoil knot that combines the use of metal helicates to create crossover points 30 , anion template assembly to form a cyclic array of the correct size [31][32][33] , and the joining of the metal complexes by reversible imine bond formation 34-37 aided by the gauche effect 38 to make the continuous 160-atom-long covalent backbone of the most complex non-DNA molecular knot prepared to date.So far, attempts to make molecular knots with more than three crossing points by extending the linear helicate strategy of Sauvage to ligands with more coordination sites...

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“…The recent rise of dynamic covalent chemistry (10) using reversible chemical reactions under thermodynamic control has led to an increasing number of catenane syntheses that are either designed to lead to a particular structure (for recent examples, see 9, 11-19) or result from unpredictable dynamic combinatorial selection (20,21). The advantage of either of these dynamic strategies is the possibility of recycling un-interlocked components, hence increasing the yield of the desired structure.…”

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confidence: 99%

Dynamic combinatorial synthesis of a catenane based on donor–acceptor interactions in water

Au‐Yeung

Pantoş

Sanders

2009

Proc. Natl. Acad. Sci. U.S.A.

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138

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A new type of neutral donor-acceptor [2]-catenane, containing both complementary units in the same ring was synthesized from a dynamic combinatorial library in water. The yield of the water soluble [2]-catenane is enhanced by increasing either buildingblock concentrations or ionic strength, or by the addition of an electron-rich template. NMR spectroscopy demonstrates that the template is intercalated between the 2 electron-deficient naphthalenediimide units of the catenane.dynamic combinatorial chemistry ͉ molecular recognition W e report here the spontaneous assembly of a donoracceptor (D-A) [2]-catenane from a dynamic combinatorial library (DCL) in water. Unusually, this is a D-A catenane that contains the electron-deficient and electron-rich aromatic moieties in the same ring. Owing to their complex topology and the resulting synthetic challenge, mechanically interlocked molecules such as catenanes have captivated chemists for a long time (1). With advances in the efficient templated synthesis of these interlocked structures, applications of these interesting molecules have been found in molecular electronic devices, such as switches, motors, color displays, and molecular memory (2-5).Conventional catenane synthesis relies on the use of noncovalent interactions to preorganize precursors in a suitable configuration that favors the formation of an interlocked structure, employing an irreversible, kinetically controlled chemical reaction as the final catenating step (for recent examples, see 6-9). The recent rise of dynamic covalent chemistry (10) using reversible chemical reactions under thermodynamic control has led to an increasing number of catenane syntheses that are either designed to lead to a particular structure (for recent examples, see 9, 11-19) or result from unpredictable dynamic combinatorial selection (20,21). The advantage of either of these dynamic strategies is the possibility of recycling un-interlocked components, hence increasing the yield of the desired structure.Interactions between electron-rich aromatics, such as dialkoxynaphthalene (DN) and tetrathiafulvalene (TTF), and electron deficient aromatics, like naphthalenediimide (NDI) and paraquat, have been extensively used in the preparation of catenanes (9,22,23). The vast majority of these catenane constructions rely on kinetically controlled reactions. Some examples of thermodynamically controlled syntheses of these structures include the neutral [2]-catenanes featuring zincpyridine coordination (24) and alkene metathesis as the ringclosing reactions (25). More recently, Stoddart and coworkers reported the iodide-catalyzed self-assembly of paraquat-based cationic D-A [2]-(16) and [3]-catenanes (14) from separate -donor and -acceptor rings using thermodynamically controlled nucleophilic substitution. Most of the examples of D-A catenane syntheses depend on a preformed, -rich crown ether ring containing electron-donor units, and the subsequent formation of new electron-deficient rings followed by catenation. Hence, the resulting catenanes...

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Amplification of Acetylcholine-Binding Catenanes from Dynamic Combinatorial Libraries

Cited by 290 publications

References 13 publications

Self-Sorting Chiral Subcomponent Rearrangement During Crystallization

Self-Sorting Chiral Subcomponent Rearrangement During Crystallization

A synthetic molecular pentafoil knot

Dynamic combinatorial synthesis of a catenane based on donor–acceptor interactions in water

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