Novel Calix[4]arene Azacrown Ether

1,3-diproyloxycalix[4]arene azacrown ether was successfully synthesized in the fixed 1,3-alternate conformation which was confirmed by a solid state structure.     

Cytotoxic 5‐Hydroxyindole Alkaloids from the Marine Sponge Scalarispongia sp.

Three new 5‐hydroxyindole alkaloids ( 1 , 2 , 3 ) along with seven known analogs ( 4 , 5 , 6 , 7 , 8 , 9 , 10 ) were isolated from a Dokdo marine sponge Scalarispongia sp. The elucidation of the structures of the new compounds by spectroscopic analyses indicated that these compounds were an indole glyoxylate ( 1 ), a mono‐indole analog of hyrtinadine A ( 2 ), and a symmetrical bis‐indole with pyridine linker ( 3 ). The comparison of IC₅₀ values for obtained compounds against a human leukemia cell line revealed that the bis‐indole structure is a requirement for cytotoxicity.     

Total synthesis of (+)-valienamine and (−)-1-epi-valienamine via a highly diastereoselective allylic amination of cyclic polybenzyl ether using chlorosulfonyl isocyanate

The total synthesis of (+)-valienamine and (−)-1-epi-valienamine was concisely accomplished from readily available d-glucose via a highly diastereoselective amination of chiral benzylic ether using chlorosulfonyl isocyanate, intramolecular olefin metathesis, and diastereoselective reduction of cyclic enone using l-Selectride as the key steps.     

After‐Rinsing Hair Growth Promotions of Hinokitiol‐Containing Vesicles and Emulsions

Two kinds of topical dosage forms of hinokitiol (HKL), namely vesicles and oil‐in‐water (O/W) emulsions, were prepared. Behenyl trimethylammonium chloride (BTMAC) and fatty acids were used as bilayer‐forming materials of the vesicles, and oils were employed as oil phases of the emulsions. The substantivity of HKL in the preparations was evaluated in vitro using hairless mouse skins. After applying the preparations onto the skin and rinsing it, the amount of HKL left on the skin was determined using high performance liquid chromatography (HPLC). It was higher when HKL was encapsulated in cationic vesicles rather than in nonionic vehicles, emulsions. An ionic interaction between the cationic vehicle and negatively charged skin is likely to account for the high substantivity. Among the emulsion preparations, an emulsion having octyl salicylate as oil phase exhibited the highest substantivity of HKL. This is probably because that the oil is a good solvent for HKL and it is skin‐retentive. In vivo hair growth‐promotion effect of each dosage form was investigated, where the sample application onto the clipped backs of female mice (C57BL6) and the subsequent rinsing of the backs were done once a day for 30 days. Only HKL in the cationic vesicles had hair growth promotion effect, possibly due to the significant substantivity.     

Analysis of cell gap-dependent driving voltage in a fringe field-driven homogeneously aligned nematic liquid crystal display

We have studied cell gap-dependent driving voltage characteristics in a homogeneously aligned nematic liquid crystal (LC) cell driven by a fringe electric field, termed the fringe field switching (FFS) mode. The results show that for the FFS mode using a LC with positive dielectric anisotropy, the operating voltage decreases as the cell gap decreases, whereas it increases with a decreasing cell gap when using a LC with negative dielectric anisotropy. The difference between LCs is explained by simulation and experiment.     

Orientational and electro-optical properties of liquid crystal aligned with a directly spinnable carbon nanotube web

We investigated the orientational and electro-optical properties of a nematic liquid crystal (LC) aligned with a directly spinnable carbon nanotube (CNT) web functioning both as an electrode and as an alignment layer. The LC molecules were uniformly oriented along the drawing direction of the CNT web and the spatially averaged birefringence was comparable to a rubbed polyimide sample. The CNT web sample also showed smaller residual DC and hysteresis compared to the polyimide sample.     

Self-assembled discotic nematic liquid crystals formed by simple hydrogen bonding between phenol and pyridine moieties

New discotic nematic liquid crystals have been prepared through intermolecular hydrogen bonding between the core of 1,3,5-trihydroxybenzene (phloroglucinol, PG) or 1,3,5-tris(4-hydroxyphenyl)benzene (THPB) and the peripheral molecules of stilbazole derivatives. The various nematic phases formed by new hydrogen bonding building blocks were investigated by differential scanning calorimetry, polarising optical microscopy and X-ray diffraction. The first discotic complexes of PG and trans-4-alkoxy-4′-stilbazoles exhibited nematic columnar (N_C) and hexagonal columnar phases depending on the length of alkyl chains, which were considered as the basic discotic structure. Several structural variations on the building blocks were attempted to examine their effects on the liquid crystalline properties of discotic complexes. The nematic lateral phase (N_L) with enhanced intercolumnar order was observed for the complexes of PG and trans-4-cyanoalkoxy-4′ stilbazoles due probably to the strong dipole interactions between cyano groups at the end of alkoxy chains. By introducing the nonlinear structure in three arms of supramolecular discotic mesogen, a discotic nematic phase (N_D) was observed for the complex of THPB and trans-4-octyloxy-4 -stilbazole. The single hydrogen bonding between phenol and pyridine moieties in this study provides a simple and effective method for preparing the rarely found discotic nematic liquid crystals.     

Self-constructed stable liquid crystal alignment in a monomer-liquid crystal mixture system

Here, we demonstrate excellent liquid crystal (LC) vertical alignment without using an alignment layer printing process by introducing octadecyltrichlorosilane (OTS) into the LC mixture. Further, we investigated the alignment mechanism by analysing the surfaces of the substrates. The optimum concentration of OTS was found to be about 0.03 wt%, which is 1/100 of that in the previously reported polyhedral oligomeric silsesquioxane (POSS)–LC system. Moreover, the OTS–LC system exhibited a more stable LC alignment compared with the POSS–LC system. These differences may arise from the different strengths of surface–dopant interactions; that is, the covalent bond in the OTS–LC system and the van der Waals interactions in the POSS–LC system. We also demonstrated that the method can be used in a capillary tube, which may serve as a new method facilitating the application of LCs with curved surfaces.     

Synthesis of Poly(benzothiadiazole‐co‐dithienobenzodithiophenes) and Effect of Thiophene Insertion for High‐Performance Polymer Solar Cells

We describe herein the synthesis of novel donor–acceptor conjugated polymers with dithienobenzodithiophenes (DTBDT) as the electron donor and 2,1,3‐benzothiadiazole as the electron acceptor for high‐performance organic photovoltaics (OPVs). We studied the effects of strategically inserting thiophene into the DTBDT as a substituent on the skeletal structure on the opto‐electronic performances of fabricated devices. From UV/Vis absorption, electrochemical, and field‐effect transistor analyses, we found that the thiophene‐containing DTBDT derivative can substantially increase the orbital overlap area between adjacent conjugated chains and thus dramatically enhance charge‐carrier mobility up to 0.55 cm² V^?1 s^?1. The outstanding charge‐transport characteristics of this polymer allowed the realization of high‐performance organic solar cells with a power conversion efficiency (PCE) of 5.1 %. Detailed studies on the morphological factors that enable the maximum PCE of the polymer solar cells are discussed along with a hole/electron mobility analysis based on the space‐charge‐limited current model.