Pairwise Packing of Anthracene Fluorophore: Hydrogen-Bonding-Assisted Dimer Emission in Solid State

Anthracene derivatives possessing a carbamate group and an ester group at their 9- and 10-positions, respectively, were prepared to furnish pairwise packing of anthracene fluorophores in their crystal structures. They were nonluminescent in ethanol solution and showed AIE (aggregation-induced emission) in aqueous ethanol solution and in solid state. Crystal structure analysis of them showed that the H-bonding networks involved in their crystal structures could be classified into four patterns, H-bonding between the carbamate and the ester carbonyl (motif A), H-bonding between the carbamate and the ester oxygen atom (motif B), H-bonded cyclic dimer of carbamate moieties (motif C), and H-bonded chain among carbamate moieties (motif D). Compounds with pairwisely packed anthracene fluorophores showed dimer emission with the longer fluorescence wavelength than others without the pair formation. Fluorescence maximum wavelengths and lifetimes become longer proportional to the degree of overlapping of two facing anthracene π-planes

Conformation-Directed Hydrogen-Bonding in <i>meta</i>-Substituted Aromatic Ureadicarboxylic Acid: A Conformationally Flexible U‑Shaped Building Block

Crystal structures of U-shaped aromatic ureadicarboxylic acid possessing two carboxy moieties at <i>meta</i>-positions of phenyl rings were investigated. It afforded cocrystals with dipyridyl derivatives. In addition to the U-shaped conformation obtained by recrystallization from methanol, another three types of U-shaped conformations were found in the crystal structure of the cocrystals. The direction of H-bonding was fixed based on the relative geometry of two carboxy moieties in the resulting conformations. Depending on these conformations, triple helices with one-dimensional water channels, infinite cross-belt, and step-like structures were generated via H-bonding between the carboxy and the pyridyl moieties. Methanol solvate was obtained for the cocrystal with 1,4-di­(pyridine-4-yl)­benzene which showed different U-shaped conformation of urea dicarboxylic acid from that involved in the cocrystal free of methanol

Crystal Structures of S‑Shaped Phenylenediurea Dibenzoic Acids and Their Cocrystals with Melamine: Unusual Zigzag Tape of H‑Bonded Melamine Network

Phenylenediurea dibenzoic acid derivatives <b>1</b>, <b>2</b>, <b>3</b>, and <b>5</b> and an amide derivative <b>4</b> were synthesized, and their molecular structures were elucidated to be an S-shape by single crystal X-ray analysis. Crystals of <b>1</b> were obtained as a DMF solvate, while those of <b>2</b> and <b>3</b> were not. Sheet and ladder structures were created in the crystal packing of <b>1</b> and <b>3</b>, and <b>2</b>, respectively. Unlike the para-substituted diureas <b>1</b>–<b>3</b> which possessed meso-conformation, the meta-substituted diurea <b>5</b> exhibited helical-conformation in its crystal structure. The way of crystal packing of <b>4</b> is analogous to that of the corresponding dicarboxylic acid derivative <b>2</b>. A water cluster of a chair-shaped hexagonal array of water molecules was created in the crystal structure of <b>4</b>. Diureas <b>1</b> and <b>2</b> gave cocrystals with melamine recrystallized from DMF/ethyl acetate and DMF/H₂O, respectively. Unusual zigzag tapes of a H-bonding network of melamine were created in both cocrystals. The zigzag tapes were connected with S-shaped diureas by H-bonding to furnish an interpenetrated fishnet-type crystal structure

Piezoluminescence and Liquid Crystallinity of 4,4′-(9,10-Anthracenediyl)bispyridinium Salts

Piezoluminescence and liquid crystallinity of anthracene-based bispyridinium salts were investigated in stimulus-responsive luminescent organic crystals and luminescent ionic liquid crystals. The salts possess an anthracene moiety as a fluorophore in their center, and the pyridiniums attached to the anthracene moiety are substituted with trialkoxybenzyl groups. Single crystals of the salts bearing two trimethoxybenzyl groups were obtained as solvates. Ethyl acetate, acetone, and dioxane solvates of the chlorides have almost the same crystal structures with one-dimensional channels. Grinding of the solvated crystals caused the extrusion of the included solvent molecules, which resulted in the red shifts of their fluorescence in the solid state. The dimethyl sulfoxide solvate of the hexafluorophosphate also showed piezoluminescene by grinding. Tris­(octyloxy)­benzyl and tris­(dodecyloxy)­benzyl derivatives exhibited rectangular columnar liquid crystals upon being heated for their bromide and tetrafluoroborate salts and upon being cooled for their hexafluorophosphate salts. Of these pyridinium salts, hexafluorophosphates showed characteristic solvent-dependent fluorescence

Simple and Efficient Chiral Dopants to Induce Blue Phases and Their Optical Purity Effects on the Physical Properties of Blue Phases

Blue phases (BPs) have received considerable attention as light shutters in the next generation of liquid crystal (LC) displays. However, no simple and efficient chiral dopant for induction of BPs of commercially available rodlike LC compounds has been reported. In this study, both (<i>R</i>) and (<i>S</i>) forms of novel chiral dopants were synthesized, showed extremely high helical twisting power values in nematic LC compounds, and induced stable BPs with a small amount of our chiral dopants (3–5 mol %). In enantiomeric excess controlled experiments, we found novel phenomena in their physical properties, such as generation of a metastable chiral nematic phase between an isotropic state and a BP

Patient characteristics (n = 118).

<p>Abbreviations: CCRT = concurrent chemoradiotherapy; UFT = uracil-tegafur; CR = complete response.</p><p>Patient characteristics (n = 118).</p

Indolylmaleimide Derivative IM-17 Shows Cardioprotective Effects in Ischemia-Reperfusion Injury

We previously developed <b>IM-54</b> as a novel type of inhibitor of hydrogen-peroxide-induced necrotic cell death. Here, we examined its cell death inhibition profile. <b>IM-54</b> was found to selectively inhibit oxidative stress-induced necrosis, but it did not inhibit apoptosis induced by various anticancer drugs or Fas ligand, or necroptosis. <b>IM-17</b>, an IM derivative having improved water-solubility and metabolic stability, was developed and confirmed to retain necrosis-inhibitory activity. <b>IM-17</b> showed cardioprotective effects in an isolated rat heart model and an <i>in vivo</i> arrhythmia model, suggesting that IM derivatives may have therapeutic potential

Comparison of disease free survival and overall survival to clinical factors (n = 118).

<p>Abbreviations: MTV = metabolic tumor volume.</p><p>Comparison of disease free survival and overall survival to clinical factors (n = 118).</p

Kaplan-Meier curves for overall survival according to MTV _{(T, 2.5)}.

<p><i>Upper line</i> MTV _{(T, 2.5)} < 4.9 ml (n = 81); <i>lower line</i> MTV _{(T, 2.5)} ≥ 4.9 ml (n = 37); <i>p</i> < 0.001 for overall survival.</p

ROC curves for patients with locoregional control according to MTV _{(T, 2.5)} status.

<p>AUC 0.846 (95% CI 0.766–0.925, <i>p</i> < 0.001), cut off value 4.9 ml for MTV _{(T, 2.5)} (n = 118). Sensitivity and specificity of the dichotomized MTV _{(T, 2.5)} (≥ 4.9 vs < 4.9) were 0.759 and 0.831, respectively.</p