Light Intensity-Selective Photopolymerization and Photoisomerization for Creating Colorful Polymer-Stabilized Cholesteric Liquid Crystal Patterns.

Polymer-stabilized cholesteric liquid crystal (PSCLC) films have been widely studied for their application as sensors, polarizers, and reflective windows. However, the preparation of programmable and colorful patterns based on the structural color is still challenging. Herein, the photochromic CLC mixtures were prepared by adding a photoisomerizable chiral additive (CA) and a photoinitiator in the nematic liquid crystal LC242.

Stereostructure Dependence Phenomenon on the Self-Assembly of Ala-Ala-Ala Lipotripeptides.

A series of lipotripeptide stereoisomers based on alanine were synthesized, and their self-assembling behaviors were studied by means of circular dichroism spectra, ATR-IR, temperature-dependent H NMR, and X-ray diffraction patterns. In the mixed solvent of hexafluoroisopropanol/HO (1/9, v/v), eight lipotripeptides were able to self-assembled into nanoflakes or nanoribbons driven by the hydrophobic association of alkyl chains, intermolecular hydrogen bonding among carboxyl groups at -terminal and amide groups of alanine moieties in the peptide segment. It was found that the stacking chirality of carbonyl groups was determined by the chirality of alanine residue at -terminal (i.

Circularly polarized luminescence from structurally coloured polymer films.

Structurally coloured polymer films with circularly polarized luminescence (CPL) properties were prepared by the photopolymerization of cholesteric liquid crystal mixtures doped with aggregation-induced emission (AIE)-active tetraphenylethylene. The films show good CPL performance with the luminescence dissymmetry factor up to 0.58 and enhanced fluorescence efficiency.

Circularly polarized luminescence of single-handed helical tetraphenylethylene-silica nanotubes.

Two single-handed helical tetraphenylethylene-silica nanotubes with circularly polarized luminescence (CPL) properties and enhanced fluorescence efficiency were fabricated through a supramolecular templating approach using the self-assemblies of chiral gelators as templates. This work provides a facile strategy for constructing CPL-active organic-inorganic hybrid nanomaterials with single-handed helical morphologies.

Helicity of perfluoroalkyl chains controlled by the self-assembly of the Ala-Ala dipeptides.

Four Ala-Ala dipeptides with a perfluoroalkyl chain at the N-terminal were synthesized. They were able to self-assemble into helical nanofibers and/or twisted nanobelts in a mixture of DMSO/H O. The handedness of nanofibers and nanobelts was controlled by the chirality of the alanine at the N-terminal.

-Type Ala-Ala Dipeptides: Odd-Even Effect in Molecular Packing Structures.

A series of -type Ala-Ala dipeptides with different alkylene bridges ( = 10-15) were synthesized. In methanol, the molecules with even-numbered carbon bridges self-assembled into twisted nanoribbons, while those with odd-numbered carbon bridges self-assembled into straight belts. The morphology displays a pronounced odd-even dependence upon the number of carbons () in the connecting alkylene bridge.

Alignment of twisted nanoribbons formed by CHCO-Val-Ala sodium salts.

C17H35CO-l-Val-l-Ala and C17H35CO-d-Val-d-Ala sodium salts can form physical gels in water, and self-assemble into right- and left-handed twisted nanoribbons, respectively. FT-IR and 1H NMR spectra indicate that the H-bonding between the neighboring valine residues and electrostatic interactions of carboxylate groups play important roles in the formation of helical nanoribbons. Circular dichroism characterization and theoretical chemical calculations indicate that the dipeptide segments pack in a helical manner.

Left-handed helical polymer resin nanotubes prepared by using N-palmitoyl glucosamine.

Although the preparation of single-handed helical inorganic and hybrid organic-inorganic nanotubes is well developed, approaches to the formation of single-handed organopolymeric nanotubes are limited. Here, left-handed helical m-phenylenediamine-formaldehyde resin and 3-aminophenol-formaldehyde resin nanotubes were prepared by using N-palmitoyl glucosamine that can self-assemble into left-handed twisted nanoribbons in a mixture of methanol and water. In the reaction mixture, the helical pitch of the nanoribbons decreased with increasing reaction time.

Aggregation-Induced Chirality: Twist and Stacking Handedness of the Biphenylene Groups of n-CHO-BP-CO-Ala-Ala Dipeptides.

In mixtures of water and dimethyl sulfoxide, 4'-(n-dodecyloxy)-1,1'-biphenyl-4-carbonyl Ala-Ala dipeptides can self-assemble into tubular structures that are formed by coiled nanoribbons. The twist and stacking handedness of biphenylene groups were studied using circular dichroism and confirmed by theoretical chemical calculations. The handedness of the coiled nanoribbons and the stacking handedness of biphenylene groups are controlled by the chirality of alanine at the C-terminus, whereas the twist handedness of biphenylene groups is determined by the chirality of alanine at the N-terminus.

Chirality-Driven Parallel and Antiparallel β-Sheet Secondary Structures of Phe-Ala Lipodipeptides.

Four Phe-Ala lipodipeptides with different stereochemical structures are observed to self-assemble into twisted nanoribbons in water. The handedness of the twisted nanoribbons is controlled by the chirality of the phenylalanine near the alkyl chain, while the stacking handedness of the phenyl and carbonyl groups is determined by the alanine at the C-terminal. The homochiral and heterochiral lipodipeptides self-assemble into parallel and antiparallel β-sheet structures, respectively.

Synthesis of Helical Phenolic Resin Bundles through a Sol-Gel Transcription Method.

Chiral and helical polymers possess special helical structures and optical property, and may find applications in chiral catalysis and optical devices. This work presents the preparation and formation process of helical phenolic resins through a sol-gel transcription method. A pair of bola-type chiral low-molecular-weight gelators (LMWGs) derived from valine are used as templates, while 2,4-dihydroxybenzoic acid and formaldehyde are used as precursors.

Preparation of Carbonaceous Hemispheres Using a Hard Templating Approach.

Silica spheres prepared using a Stöber method were covered with 4,4'-biphenylene-bridged polybissilsesquioxane to form a core-shell structure. After carbonization, and the removal of the silica, carbonaceous hemispheres were obtained. The hemispheres were formed because of the collapse and shrinkage of the hollow spheres.

Control of the Handedness of Self-assemblies of Dipeptides by the Chirality of Phenylalanine and Steric Hindrance of Phenylglycine.

Eight dipeptides, composed of phenylalanine and phenylglycine, that are able to self-assemble into twisted nanoribbons in deionized water are synthesized. The handedness of the nanoribbons is controlled by the chirality of the phenylalanine and the steric hindrance owing to the phenyl group of the phenylglycine. When the phenylalanine is at the C-terminal, π-π stacking by the phenyl groups, hydrogen bonding by the NH group of the phenylalanine, and hydrophobic associations of the alkyl chains control the stacking of the molecules.

Achiral Polydialkylsilane Aggregates That Record Stirring Direction.

Achiral polysilane aggregates can recognize the chirality of low-molecular-weight compounds. It was found that they can also record the stirring direction. Poly(n-decyl-2-methylpropylsilane), poly(n-nonyl-2-methylpropylsilane), poly(n-decyl-2-ethylbutylsilane), and poly(n-decyl-(S)-2-methylbutylsilane) aggregates were prepared in a mixture of tetrahydrofuran/isopropanol.

A Novel Class of HIV-1 Antiviral Agents Targeting HIV via a SUMOylation-Dependent Mechanism.

We have recently identified a chemotype of small ubiquitin-like modifier (SUMO)-specific protease (SENP) inhibitors. Prior to the discovery of their SENP inhibitory activity, these compounds were found to inhibit HIV replication, but with an unknown mechanism. In this study, we investigated the mechanism of how these compounds inhibit HIV-1.

Helical Polybissilsesquioxane Bundles Prepared Using a Self-Templating Approach.

Polybissilsesquioxanes with single-handed helical morphologies attracted much attention during the last decade, which could be applied as asymmetric catalysts and chiral stationary phases. Herein, a pair of chiral biphenylene-bridged bissilsesquioxanes were synthesized. They self-assembled into helical bundles in ethanol, behavior that was confirmed in field emission scanning electron microscopy images.

Chirality of 4,4'-Biphenylene Bridged Polybissilsesquioxane Nanotubes Using the Dipeptides Derived from Valine.

Four dipeptides with alkyl chains derived from L- and D-valines were synthesized, the handedness of their self-assemblies were controlled by the valine chirality at the terminals. The stacking of the carbonyl groups plays an important in the formation of chiral organic self-assemblies. Chiral 4,4'-biphenylene bridged polybissilsesquioxane nanotubes were prepared using the self-assemblies of these dipeptides as the templates.

Inner Surface Chirality of Single-Handed Twisted Carbonaceous Tubular Nanoribbons.

Single-handed twisted 4,4'-biphenylene-bridged polybissilsesquioxane tubular nanoribbons and single-layered nanoribbons were prepared by tuning the water/ethanol volume ratio in the reaction mixture at pH = 11.6 through a supramolecular templating approach. The single-layered nanoribbons were formed by shrinking tubular nanoribbons after the removal of the templates.

Chirality of Single-Handed Twisted Titania Tubular Nanoribbons Prepared Through Sol-gel Transcription.

Single-handed twisted titania tubular nanoribbons were prepared through sol-gel transcription using a pair of enantiomers. Handedness was controlled by that of the template. The obtained samples were characterized using field-emission electron microscopy, transmission electron microscopy, diffuse reflectance circular dichroism (DRCD), and X-ray diffraction.

Design of high-throughput screening assays and identification of a SUMO1-specific small molecule chemotype targeting the SUMO-interacting motif-binding surface.

Protein-protein interactions are generally challenging to target by small molecules. To address the challenge, we have used a multidisciplinary approach to identify small-molecule disruptors of protein-protein interactions that are mediated by SUMO (small ubiquitin-like modifier) proteins. SUMO modifications have emerged as a target with importance in treating cancer, neurodegenerative disorders, and viral infections.

Chiral carbonaceous nanotubes containing twisted carbonaceous nanoribbons, prepared by the carbonization of chiral organic self-assemblies.

Single-handed helical silica nanotubes containing chiral organic self-assemblies were prepared by using a supramolecular templating approach. After carbonization and the removal of the silica, single-handed helical carbonaceous nanotubes that contained twisted carbonaceous nanoribbons were obtained. It is believed that the nanotubes formed as a result of the adsorption of low-molecular-weight gelators.

Preparation of single-handed helical carbon/silica and carbonaceous nanotubes by using 4,4'-biphenylene-bridged polybissilsesquioxane.

Single-handed, helical, 4,4'-biphenylene-bridged polybissilsesquioxane nanotubes were prepared by using the self-assemblies of a pair of chiral low-molecular-weight gelators as templates. Single-handed, helical, carbon/silica nanotubes were obtained after carbonization of the self-assemblies, and single-handed helical carbonaceous nanotubes were then obtained by removal of silica with aqueous HF. Samples were characterized by using field-emission SEM, TEM, X-ray diffraction, thermogravimetric analysis, Raman spectroscopy, and circular dichroism.

Solvent-induced handedness inversion of dipeptide sodium salts derived from alanine.

The relationship between amino acid sequences and their resulting nanostructure has been well studied, but that between amino acid chirality and nanostructure handedness has not. Four dipeptide sodium salts with long alkyl chains derived from L- and D-alanines were synthesized. The behavior of their self-assembly into physical gels in water and THF was studied using field-emission scanning electron microscopy, circular dichroism (CD), FT-IR spectroscopy, (1)H NMR spectroscopy, and X-ray diffraction.

A chirality indicator for the surfaces of the silica nanotubes.

The chirality of the silicas attracted much attention, due to their potential applications in asymmetric catalysis and enantioseparation. However, their chirality has not been well understood. Herein, a chirality indicator for the surfaces of the silica nanotubes was developed.