Helicene‐Grafted Silica Nanoparticles Capture Hetero‐Double‐Helix Intermediates during Self‐Assembly Gelation

Miyagawa, Masamichi; Yamaguchi, Masahiko

doi:10.1002/chem.201406482

Cited by 9 publications

(10 citation statements)

References 24 publications

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“…507 This equilibrium shift using chiral NPs has been further applied to the system for the selective precipitation of heterodouble-helix intermediates during gelation by selfassembly and also to the rhodium-catalyzed disulfide exchange reaction, through which an optically active diol disulfide was obtained by kinetic resolution combined with an equilibrium shift. 508,509 A cyclic oligomer ((M)-336) consisting of two linear ethynyl [4]helicene oligomers connected through two flexible hexadecyl linkers (Figure 101A) 510 undergoes a reversible structural transformation between random coil and an intramolecular homodouble helix in response to temperature and solvents. In the presence of a pseudoenantiomeric linear oligomer ((P)-325a) (n = 5), (M)-336 formed an intermolecular ternary complex with heterodouble helices, which further self-assembled to form lyotropic liquid crystals, in which fibers were anisotropically aligned at high concentrations.…”

Section: Multistranded Helical Assembliesmentioning

confidence: 99%

“…In the presence of the ( P )-NPs, its equilibrium was shifted to the double-helix (58%) because of selective precipitation of the double-helix with the ( P )-NPs (Figure B) . This equilibrium shift using chiral NPs has been further applied to the system for the selective precipitation of heterodouble-helix intermediates during gelation by self-assembly and also to the rhodium-catalyzed disulfide exchange reaction, through which an optically active diol disulfide was obtained by kinetic resolution combined with an equilibrium shift. , …”

Section: Multistranded Helical Assembliesmentioning

confidence: 99%

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Supramolecular Helical Systems: Helical Assemblies of Small Molecules, Foldamers, and Polymers with Chiral Amplification and Their Functions

et al. 2016

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In this review, we describe the recent advances in supramolecular helical assemblies formed from chiral and achiral small molecules, oligomers (foldamers), and helical and nonhelical polymers from the viewpoints of their formations with unique chiral phenomena, such as amplification of chirality during the dynamic helically assembled processes, properties, and specific functionalities, some of which have not been observed in or achieved by biological systems. In addition, a brief historical overview of the helical assemblies of small molecules and remarkable progress in the synthesis of single-stranded and multistranded helical foldamers and polymers, their properties, structures, and functions, mainly since 2009, will also be described.

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Section: Multistranded Helical Assembliesmentioning

confidence: 99%

Section: Multistranded Helical Assembliesmentioning

confidence: 99%

Supramolecular Helical Systems: Helical Assemblies of Small Molecules, Foldamers, and Polymers with Chiral Amplification and Their Functions

et al. 2016

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“…Silica nanoparticles efficiently recognize the structure of the homo-double-helix cylindrical molecular complexes [ 104 , 105 , 106 , 107 , 108 ]. Aminopropylated silica nanoparticles with an average diameter of 70 nm were grafted with ( P )-helicene acid chloride.…”

Section: Self-assembly Of Nanoparticles With Double-helix Chiral Cmentioning

confidence: 99%

“…The ( P )-nanoparticles recognized also hetero-double-helices, which were intermediates in the self-assembly gel formation and removed the chiral cylindrical molecular complexes from the solution phase by precipitation ( Figure 35 ) [ 107 ]. A toluene solution of the ethynylhelicene ( P )-pentamer and ( M )-tetramer containing ( P )-nanoparticles was heated to 100 °C and cooled to 25 °C to form a self-assembly gel.…”

Section: Self-assembly Of Nanoparticles With Double-helix Chiral Cmentioning

confidence: 99%

Synthesis and Self-Assembly of Chiral Cylindrical Molecular Complexes: Functional Heterogeneous Liquid-Solid Materials Formed by Helicene Oligomers

Saito

Yamaguchi

2018

Molecules

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Chiral cylindrical molecular complexes of homo- and hetero-double-helices derived from helicene oligomers self-assemble in solution, providing functional heterogeneous liquid-solid materials. Gels and liotropic liquid crystals are formed by fibril self-assembly in solution; molecular monolayers and fibril films are formed by self-assembly on solid surfaces; gels containing gold nanoparticles emit light; silica nanoparticles aggregate and adsorb double-helices. Notable dynamics appears during self-assembly, including multistep self-assembly, solid surface catalyzed double-helix formation, sigmoidal and stairwise kinetics, molecular recognition of nanoparticles, discontinuous self-assembly, materials clocking, chiral symmetry breaking and homogeneous-heterogeneous transitions. These phenomena are derived from strong intercomplex interactions of chiral cylindrical molecular complexes.

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“…Different combinations of pseudoenantiomeric oligomers again were used to tune vesicle properties. The combinations of (P)-10 (n = 5)/(M)-11 (n = 4) and (P)-10 (n = 5)/(M)-10 (n = 4) gave vesicles of different sizes and shapes.Hetero-double-helices, being intermediates in gel formation, can be captured and isolated by the silica (P)-nanoparticle precipitation method, which is a novel method to isolate a reaction intermediate (68). When (P)-nanoparticles were added to the mixture of the pseudoenantiomeric helicene oligomers (P)-10 (n = 5) and (M)-10 (n = 4), hetero-double-helices were adsorbed on the (P)-nanoparticles and removed from the solution by aggregation and precipitation.…”

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confidence: 99%

Structure and Property Diversity of Chiral Helicene Oligomers

Saito

Shigeno

Yamaguchi

2015

Encyclopedia of Polymer Science and Technology

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alkylthio, and perfluoroalkyl groups. In addition, cyclization of helicene oligomers provides another method of obtaining diversity.A notable aspect in the diversity of helicene oligomers is that they can be connected to provide multidomain oligomers (Fig. 4). When two helicene oligomers are connected, they are referred to herein as homo-bidomain oligomers. Cyclic homo-bidomain oligomers are also conceivable. Hetero-multidomain oligomers can be obtained by connecting different structures of oligomers. Such manipulations provide a large diversity of structures.Because helicene can generate characteristic π−π interactions, helicene oligomers often form bimolecular, trimolecular, tetramolecular, and polymolecular aggregates in which homoaggregation and heteroaggregation can also occur. Such aggregates self-assemble to form fibrils, vesicles, liquid crystals, and surface monolayers. These noncovalent bonding interactions provide diversity of the structure of helicene oligmers. Diverse Properties of Helicene OligomersStructural diversity is directly related to diversity of properties, and the properties of a helicene oligomer can be varied by structural modifications. In addition, multidomain oligomers can be designed, in which properties A and B of each domain can be combined. Such compounds exhibit property A + B or even another property C, a result regarded as the "synthesis of a property or function." Aggregation and self-assembly of helicene oligomers further increase property diversity, which covers materials with a broad range of sizes from subnanometersized molecules through nano-and micrometer-sized molecular aggregates and molecular self-assemblies to macroscopic bulk materials. Helicene oligomers are sensitive to changes in the environment such as temperature, solvent, and concentration. Different properties appear in dilute solution, in concentrated Amidohelicene oligomers: (a) acylcic oligomers (P)-1 (n = 1−9) with dianiline spacer, cyclic oligomers (P)-2 (n = 1−10) with dianiline spacer, (b) acyclic oligomers (P)-3 (n = 1−9) with m-phenylene spacer, and acyclic reverse oligomers (P)-4 (n = 1−4). (c) Schematic representation of reversible change between helix dimer and random coils of (P)-3 and (P)-4. solution, in the crystalline state, in the amorphous state, on the solid surface, at the solid-liquid interface, in fiber assemblies, in liquid crystals, and in gels. Dynamic properties of helicene oligomers are also interesting, and structural changes are largely affected by the environment, providing a stimulus response or possible molecular switching materials. It is also noteworthy that the process of a structure change can produce unusual transient phenomena. Amidohelicene OligomersStudies on helicene oligomers were initiated with amide derivatives (Fig. 5a, top), in which the spacer has a bent shape and includes both hydrogen bonding donor and acceptor moieties (24). (P)-5,8-Helicenedicarboxylate was reacted with bis(2,6-dimethylanilino)cyclohexane to give a series of acyclic helicene oligomers 1 up t...

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Helicene‐Grafted Silica Nanoparticles Capture Hetero‐Double‐Helix Intermediates during Self‐Assembly Gelation

Cited by 9 publications

References 24 publications

Supramolecular Helical Systems: Helical Assemblies of Small Molecules, Foldamers, and Polymers with Chiral Amplification and Their Functions

Supramolecular Helical Systems: Helical Assemblies of Small Molecules, Foldamers, and Polymers with Chiral Amplification and Their Functions

Synthesis and Self-Assembly of Chiral Cylindrical Molecular Complexes: Functional Heterogeneous Liquid-Solid Materials Formed by Helicene Oligomers

Structure and Property Diversity of Chiral Helicene Oligomers

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