Self-Assembly of Disk-Shaped Molecules to Coiled-Coil Aggregates with Tunable Helicity

Engelkamp, Hans; Middelbeek, S.; Nolte, Roeland J. M.

doi:10.1126/science.284.5415.785

Cited by 743 publications

(452 citation statements)

References 17 publications

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“…This self-assembly system relates to other processes in which a stereocenter selects the twist sense of a racemic helical structure (10,23,24) and is in agreement with the principles elaborated by Green et al (25). However, it differs from those in which a stereocenter induces helicity in an achiral nonhelical system (26). Other examples of helical supramolecular dendrimers selfassembled from achiral dendrons are known (27,28).…”

Section: Structural Analysis Of Oriented Fibers By Xrd and Self-assemsupporting

confidence: 50%

Principles of self-assembly of helical pores from dendritic dipeptides

Percéc

Dulcey

Peterca

et al. 2006

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

123

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The self-assembly of the dendritic dipeptides (4-3,4-3,5)nG2-CH2-Boc-L-Tyr-L-Ala-OMe and their achiral dendritic alcohol (4-3,4-3,5)nG2-CH2OH precursors, both with n ‫؍‬ 1-16, where n represents the number of methylenic units in the alkyl groups of the dendron, are reported. All chiral dendritic dipeptides and achiral dendritic alcohols self-assemble into helical porous columns that are stable in both solution and solid state. The pore diameter (Dpore) of the columns self-assembled from dendritic dipeptides is Ϸ10 Å larger than that of structures assembled from dendritic alcohols. The increase of the Dpore at the transition from dendritic alcohol to dendritic dipeptide is accompanied by a decreased solid angle of the building block. This trend is in agreement with previous pore size-solid angle dependences observed with different protective groups of the dipeptide and primary structures of the dendron. However, within the series of dendritic alcohols and dendritic dipeptides with various n, the Dpore increases when the solid angle increases. The results of these investigations together with those of previous studies on the role of dipeptide stereochemistry and protective groups on this self-assembly process provide the molecular principles required to program the construction of supramolecular helical pores with diameter controlled at the Å level from a single dendritic dipeptide architecture. These principles are expected to be valid for libraries of dendritic dipeptides based on dendrons and dipeptides with various primary structures. chiral dendrons ͉ porous supramolecular columns ͉ protein mimics ͉ peptide stereochemistry N atural porous proteins function as viral helical coats (1), transmembrane channels (2, 3), antibiotics (4), and pathogens (5), and their remodeled structures are used in synthetic systems for reversible encapsulation (6) and stochastic sensing (7). With few exceptions (8-10) porous protein mimics do not assemble, as the natural porous proteins do, into periodically ordered structures that are stable in both solution and bulk (11)(12)(13)(14). This behavior limits their structural analysis by combinations of solution and solid-state complementary techniques. Recently our laboratory (15) reported the self-assembly of amphiphilic dendritic dipeptides into helical porous structures that are stable in both solution and bulk (15). Preliminary reports have demonstrated that the internal structure and the stability of the porous columns self-assembled from dendritic dipeptides are programmed by the structure and stereochemistry of the dipeptide (15, 16), the protective groups of the dipeptide (17), and the structure of the dendron (18) attached to the dipeptide. Here we are reporting a comparative study of the self-assembly and structural and retrostructural analysis of the supramolecular porous structures generated from libraries of (4-3,4-3,5)nG2-CH 2 -Boc-L-Tyr-L-Ala-OMe dendritic dipeptides and their achiral (4-3,4-3,5)nG2-CH 2 OH precursors with n ϭ 1-16. This series of experiments will prov...

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Section: Structural Analysis Of Oriented Fibers By Xrd and Self-assemsupporting

confidence: 50%

Principles of self-assembly of helical pores from dendritic dipeptides

Percéc

Dulcey

Peterca

et al. 2006

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

123

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“…Covalent, but more often non covalent intermolecular forces have been used to engineer highly ordered three dimensional supramolecular architectures where the single building blocks are held together by specific interactions, such as metal ligand bonding, [85]- [87] hydrogen bonding [88]- [91] and stacking. [92] On the other hand, self assembly at the solid liquid interface has been successfully used to control the molecular arrangement in two dimensions. [91][93]…”

Section: Immobilization Of Organic Moleculesmentioning

confidence: 99%

Shape‐Switchable Azo‐Macrocycles

et al. 2009

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The synthesis of four shape‐switchable macrocycles comprising different peripheral substituents is described. The macrocycles 1–4 consist of m‐terphenyl semicircles interlinked by two azo joints. These macrocycles were assembled from nitro‐functionalized m‐terphenyl moieties through reductive dimerization. The semicircles were assembled through Suzuki cross‐coupling reactions. The molecular weights of the macrocycles were determined by vapour pressure osmometry, because mass spectrometry failed in the cases of 2 and 3. The E → Z photoisomerization reactions were analysed by UV/Vis spectroscopy complemented by 1H NMR studies. A very slow thermal back‐reaction indicated considerable stabilization of the Z isomer. The reduced efficiency of the thermal back‐reaction probably arises from the reduced degree of freedom due to the mechanical interlinking of the two azo groups. The photostationary state consisted of all‐Z (85 %) and all‐E isomers (15 %). The E → Z transformation induced by irradiation displayed simple exponential kinetics, which indicates pairwise switching of the two azo groups in a macrocycle, at least on the timescale under investigation. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)

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“…For example, discotic molecules in crystalline or liquid crystalline states often exhibit helical order in columnar arrangements (2-6), and such materials are attractive for use in optoelectronic devices because of the exceptional 1D charge-carrier mobilities along the columns (2-4). A common route to induce helicity in columnar arrangements is inclusion of chiral centers in discotic molecules (7). Helical columnar arrangements have also been realized in a few cases with achiral discotic molecules (8,9), although no general strategy seems to have emerged.…”

mentioning

confidence: 99%

Rational design of helical architectures

Chakrabarti¹,

Fejer²,

Wales³

2009

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

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Nature has mastered the art of creating complex structures through self-assembly of simpler building blocks. Adapting such a bottom-up view provides a potential route to the fabrication of novel materials. However, this approach suffers from the lack of a sufficiently detailed understanding of the noncovalent forces that hold the self-assembled structures together. Here we demonstrate that nature can indeed guide us, as we explore routes to helicity with achiral building blocks driven by the interplay between two competing length scales for the interactions, as in DNA. By characterizing global minima for clusters, we illustrate several realizations of helical architecture, the simplest one involving ellipsoids of revolution as building blocks. In particular, we show that axially symmetric soft discoids can self-assemble into helical columnar arrangements. Understanding the molecular origin of such spatial organisation has important implications for the rational design of materials with useful optoelectronic applications.anisotropic interactions ͉ columnar arrangements ͉ helix ͉ self-assembly N ature provides ubiquitous examples of helical architecture with diverse functions. Helical structures are common structural motifs in biomolecules and are involved in the storage of genetic information (1). They are also important in solid-and liquid-crystal engineering for fabricating functional materials with useful optoelectronic applications (2-5). For example, discotic molecules in crystalline or liquid crystalline states often exhibit helical order in columnar arrangements (2-6), and such materials are attractive for use in optoelectronic devices because of the exceptional 1D charge-carrier mobilities along the columns (2-4). A common route to induce helicity in columnar arrangements is inclusion of chiral centers in discotic molecules (7). Helical columnar arrangements have also been realized in a few cases with achiral discotic molecules (8, 9), although no general strategy seems to have emerged.Self-assembly is nature's prescription for the creation of complex structures from simpler building blocks (10, 11). Although many novel building blocks have been discovered for self-assembly, differing in shape, composition, and functionality (12, 13), the basic rules that govern this process are not yet understood in sufficient detail to realize target structures routinely through a priori design of building blocks. Here we ask the specific question: Can we learn from nature how to design building blocks that self-assemble into helical structures? In seeking a guiding principle from nature for obtaining helical architectures, we considered DNA, in which two competing length scales exist, one characterizing the distance between consecutive nucleotides in the sugar-phosphate backbone and the other governing the stacking of the base pairs (1). The present contribution thus explores realizations of helical architectures with achiral building blocks driven by the interplay between two competing length scales. To this end, we c...

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Self-Assembly of Disk-Shaped Molecules to Coiled-Coil Aggregates with Tunable Helicity

Cited by 743 publications

References 17 publications

Principles of self-assembly of helical pores from dendritic dipeptides

Principles of self-assembly of helical pores from dendritic dipeptides

Shape‐Switchable Azo‐Macrocycles

Rational design of helical architectures

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