Preparation and characterization of helical self-assembled nanofibers

Lee, Cameron C.; Grenier, Christophe R. G.; Meijer, E. W.; Schenning, Albertus P. H. J.

doi:10.1039/b800407m

Cited by 359 publications

(269 citation statements)

References 41 publications

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“…Taking into account that compound 3 lacks any additional attractive secondary interaction or chiral substituent to induce the helicity, its helical organization could be justified by the local dipole moments present between the C À O bonds of the peripheral wedges. [26] To the best of our knowledge, this is the first time that a mixture of M and P columnar stacks is visualized by AFM from the deposition of an achiral molecule onto a surface.…”

Section: D)mentioning

confidence: 98%

Mirror Helices and Helicity Switch at Surfaces Based on Chiral Triangular‐Shape Oligo(phenylene ethynylenes)

Aparicio

García

Fernández

et al. 2011

Chemistry A European J

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The self-assembly of triangular-shaped oligo(phenylene ethynylenes) (OPEs), peripherally decorated with chiral and linear paraffinic chains, is investigated in bulk, onto surfaces and in solution. Whilst the X-ray diffraction data for the chiral studied systems display a broad reflection centered at 2θ ∼20° (λ=Cu(Kα)), the higher crystallinity of OPE 3, endowed with three linear decyl chains, results in a diffractrogram with a number of well-resolved reflections that can be accurately indexed as a columnar packing arranged in 2D oblique cells. Compounds (S)-1 a and (R)-1 b-endowed with (S)- and (R)-3,7-dimethyloctyloxy chains-transfer their chirality to the supramolecular structures formed upon their self-assembly, and give rise to helical nanostructures of opposite handedness. A helicity switch is noticeable for the case of chiral (S)-2 decorated with (S)-2-methylnonyloxy chains which forms right-handed helices despite it possesses the same stereoconfiguration for their stereogenic carbons as (S)-1 a that self-assembles into left-handed helices. The stability and the mechanism of the supramolecular polymerization in solution have been investigated by UV/Vis experiments in methylcyclohexane. These studies demonstrate that the larger the distance between the stereogenic carbon and the aromatic framework is, the more stable the aggregate is. Additionally, the self-assembly mechanism is conditioned by the peripheral substituents: whereas compounds (S)-1 a and (R)-1 b self-assemble in a cooperative manner with a low degree of cooperativity, the aggregation of (S)-2 and 3 is well described by an isodesmic model. Therefore, the interaction between the chiral coil chains conditions the handedness of the helical pitch, the stability of the supramolecular structure and the supramolecular polymerization mechanism of the studied OPEs.

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Section: D)mentioning

confidence: 98%

Mirror Helices and Helicity Switch at Surfaces Based on Chiral Triangular‐Shape Oligo(phenylene ethynylenes)

Aparicio

García

Fernández

et al. 2011

Chemistry A European J

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“…Supramolecular self-assembly, which makes use of molecules instead of atomic units, offers a bottom-up approach to the construction of new materials on multiple length scales without complex organic synthesis [1][2][3][4][5][6][7][8][9][10]. The driving forces for supramolecular chemistry are noncovalent interaction ranging from host-guest interaction [11], hydrogen bonding [12], van der Waals interaction [13], π─π stacking [14], electrostatic interactions [15] and hydrophobic effect [16].…”

Section: Introductionmentioning

confidence: 99%

Supramolecular Materials Based on Ionic Self‐Assembly: Structure, Property, and Application

Shen¹,

Yuan²,

Xin³

2017

Molecular Self-Assembly in Nanoscience and Nanotechnology

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The technique of ionic self-assembly (ISA), on the basis of electrostatic interactions, is a powerful tool to create new material nanostructures and chemical objects due to its advantages of facility, reliability, cost saving, flexibility, and universality. It has attracted great attention because of its promising applications in catalysis, drug delivery, and molecular detection. This review focuses on recent advances in the construction of self-assemblies with different morphologies on the basis of ISA strategy and its applications. The ISA method provides an opportunity to generate complex and hierarchical assemblies with tunable properties, which is regarded as a very promising case of supramolecular chemistry.

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“…Furthermore, we prepared chiral derivatives of these three compounds, (S)-CN 0 , (S)-CN 1 , and (S)-CN 2 (Figure 1), and investigated their circular dichroism (CD) profiles in MCH. As expected, (S)-CN 2 exhibits a clear CD signal, suggesting the formation of helical supramolecular polymers, 9 whereas both (S)-CN 1 and (S)-CN 0 are CD-silent ( Figure 3a). From these data, it is clear that the presence of two cyano groups aid the formation of supramolecular polymers in MCH, possibly by strengthening ππ interactions between CN 2 monomers and through dipoledipole interactions.…”

mentioning

confidence: 84%

Unexpected Effect of Cyano Groups on the Supramolecular Polymerization of Amide-appended Fan-shaped Monomers

Imayoshi¹,

Rao²,

Nihonyanagi³

et al. 2017

Chem. Lett.

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Effects of a small functional group, cyano, on the supramolecular polymerization of fan-shaped monomers were investigated. When cyano groups are replaced by hydrogen atoms, the resultant monomers surprisingly fail to undergo supramolecular polymerization and exist as monomers in methylcyclohexane (MCH). Moreover, in the mixed monomer systems, we successfully visualized a small difference in the self-assembling behaviors, which was dependent on the number of cyano groups.Keywords: Supramolecular polymer | Self-assembly | Hydrogen-bond Supramolecular polymers are macromolecules, in which monomers are connected via non-covalent interactions.1 In general, individual non-covalent interactions are not sufficiently strong enough to connect two molecules tightly. Hence, most monomers for supramolecular polymers are designed to take advantage of the cooperative interaction of multiple noncovalent interactions, such as hydrogen bonding (H-bonding) and ππ interactions. Thanks to contributions from many researchers, several structural motifs, such as amide groups and large aromatic cores, have been demonstrated to form supramolecular polymers.1,2 Furthermore, it has been recently reported that the molecular geometries of monomers largely affect their supramolecular polymerization capabilities.3,4 On the other hand, the effect of small functional groups on the selfassembling properties of monomers has been relatively ignored. Meijer et al. showed that by replacing a hydrogen with a deuterium atom in the side chains of their monomers, onehanded helical supramolecular polymers could be obtained. 5Due to the paucity of examples, it is worth investigating the effects of small functional groups on the self-assembling behaviors of supramolecular monomers in order to expand their scope and possibilities. Here we report on the unique supramolecular polymerizations of fan-shaped molecules in solution that can be drastically influenced by one small functional group, the cyano group. Furthermore, we successfully visualized a small difference in their self-assembling behaviors, originating from the presence or absence of one cyano group.We have reported that CN 0 and CN 2 (Figure 1) form columnar liquid crystalline phases over wide temperature ranges by forming intermolecular H-bonds between amide groups in the solid state. 6 We herein investigated their self-assembling behaviors in methylcyclohexane (MCH) together with the newly synthesized CN 1 (Figure 1). From the molecular structures, one would expect that, all these molecules self-assemble in lowpolarity solvents, such as MCH, irrespective of the number of cyano groups because both CN 0 and CN 2 have been shown to form columnar liquid crystalline phases.6c However, our investigations revealed that these systems have significant differences in their self-assembling behaviors in MCH.As shown in Figure 2a, dynamic light scattering (DLS) measurements of MCH solutions (0.1 mM) of CN 1 and CN 0 exhibited unimodal scattering profiles at 20°C with a hydrodynamic diameter of ca. 0.6 nm, su...

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Preparation and characterization of helical self-assembled nanofibers

Abstract: This tutorial review serves as an introduction to helical self-assembled systems, illustrated by a specific class of helical aggregates: helical nanofibers. The common ways by which these systems are designed, prepared, and characterized will be presented.

Cited by 359 publications

References 41 publications

Mirror Helices and Helicity Switch at Surfaces Based on Chiral Triangular‐Shape Oligo(phenylene ethynylenes)

Mirror Helices and Helicity Switch at Surfaces Based on Chiral Triangular‐Shape Oligo(phenylene ethynylenes)

Supramolecular Materials Based on Ionic Self‐Assembly: Structure, Property, and Application

Unexpected Effect of Cyano Groups on the Supramolecular Polymerization of Amide-appended Fan-shaped Monomers

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