Performance of Particle Swarm Optimization in Predicting the Orientation of π-Conjugated Molecules Inside Carbon Nanotubes Compared with Density Functional Theory Calculations.

Particle swarm optimization (PSO) was employed to obtain the global minimum of host-guest structures consisting of a triiodobenzene molecule (BzI) inside an armchair (,) nanotube (BzI@(,)), whose host-guest interactions are approximated by Lennard-Jones (LJ) potentials. The host-guest structures obtained using the PSO-LJ method were then compared with those obtained through dispersion-corrected density functional theory (DFT) calculations to evaluate the performance of the PSO-LJ approach in predicting the guest orientation inside a tube. When the inner space of the host tube is limited for guest encapsulation, the PSO-LJ method can reproduce the DFT results of BzI@(,) in terms of the guest orientation.

Experimental and Computational Insights into the Catalytic Mechanism of YBaCoO Perovskite Oxides with a Controlled Crystal Structure.

The crystal structure of Co-based perovskite oxides (ACoO) can be controlled by adjusting the A-site elements. In this study, we synthesized YBaCoO ( = 0, 0.5, and 1.

Experimental and Theoretical Studies on Cobalt-Catalyzed Regioselective Hydrosilylation of Tetrafluorinated Cyclohexa-1,3-dienes.

Cyclohexa-1,3-dienes bearing a tetrafluoroethylene group underwent highly regioselective hydrosilylation in the presence of 1-10 mol % Co(CO) in 1,2-dichloroethane under mild conditions (reflux, 3 h), which led to an abundant yield of homoallylsilanes. Mechanistic studies proved that the reaction proceeds as per the modified Chalk-Harrod mechanism; via DFT calculation, the reason for homoallylsilanes being exclusively obtained was demonstrated. The formal synthesis of a tetrafluorinated negative-type liquid crystal demonstrated the synthetic utility of such hydrosilylation.

Roles of Carbon Nanotube Confinement in Modulating Regioselectivity of 1,3-Dipolar Cycloadditions.

DFT-based calculations were employed to investigate mechanisms of 1,3-dipolar cycloadditions between phenylacetylene and an azide (phenylazide or benzylazide) inside carbon nanotubes, whose diameters range from 10 to 14 Å, by obtaining their reaction species (reactant complex, transition state (TS), and product (Pro)). The reactions yield 1,4- and 1,5-triazoles, whose paths are denoted by 1,4- and 1,5-approaches, respectively. We found different geometrical features of reaction species between 1,4- and 1,5-approaches.

Theoretical understanding of stability of mechanically interlocked carbon nanotubes and their precursors.

Dispersion-corrected DFT calculations were performed on (,) nanotubes ( = 5-10) attached by a U-shaped functional group consisting of -xylene-linked double 9,10-di(1,3-dithiol-2-ylidene)-9,10-dihydro anthracene terminated by CH chains ( = 6, 8, and 9), and their ring-closing macrocycles containing tubes. The reactant precursors and macrocycles are denoted by UP--(,) and (,)@Cycle-, respectively. We found that UP--(,) are energetically preferable relative to the dissociation limit toward a U-shaped functional group (UP-) and a tube (initial state) due to the attractive CH-π and π-π interactions.

Ultralong Distance Hydrogen Spillover Enabled by Valence Changes in a Metal Oxide Surface.

Hydrogen spillover is a phenomenon in which hydrogen atoms generated on metal catalysts diffuse onto catalyst supports. This phenomenon offers reaction routes for functional materials. However, due to difficulties in visualizing hydrogen, the fundamental nature of the phenomenon, such as how far hydrogen diffuses, has not been well understood.

Tertiary arsine ligands for the Stille coupling reaction.

The Stille coupling reaction is one of the most important coupling reactions. It is well known that the triphenylarsine ligand can accelerate the reaction rate of Stille coupling. However, other arsine ligands have never been investigated for the Stille coupling reaction so far.

Homo- and hetero-metallophilicity-driven synthesis of highly emissive and stimuli-responsive Au(I)-Cu(I) double salts.

Complex salts composed of cationic Au(i) and anionic Cu(i) species were synthesized by utilizing bis(diphenylarsino)methane (dpam) and bis(diphenylphosphino)methane (dppm) ligands. The discrete tetranuclear complexes were obtained as crystals, and the four-metal chain, CuAuAuCu, was linked through homo- and hetero-metallophilic interactions. Three crystal polymorphs were obtained for the dpam- and dppm-complexes, depending on the recrystallization solvent.

Dibenzoarsacrowns: an experimental and computational study on the coordination behaviors.

Dibenzoarsacrowns have been synthesized as a novel class of heteroatom-fused crown ethers. The dibenzoarsacrowns can size-selectively capture alkali metal cations, and the arsenic atoms chemoselectively coordinated to gold(i) chloride (AuCl) due to the soft Lewis acid-base interaction. It is notable that the AuCl complex of 21-dibenzoarsacrown-7 further encapsulated Na with the enhanced association constant from bare 21-dibenzoarsacrown-7.

Systematic Study on the Catalytic Arsa-Wittig Reaction.

Efficient catalytic arsa-Wittig reactions have been developed by using 1-phenylarsolane as a catalyst. A wide array of aldehydes was converted to the corresponding olefins in high yields with moderate to excellent E stereoselectivity in the presence of a catalytic amount of 1-phenylarsolane. Moreover, density functional theory calculations were carried out to afford insight into the E/Z selectivity.

Fluorinated porous molecular crystals: vapor-triggered on-off switching of luminescence and porosity.

A platinum diiodide complex with 9-pentafluorophenyl-9-arsafluorene formed a porous molecular crystal (PMC) or a non-porous molecular crystal (n-PMC), depending on the recrystallization solvents. Vapor exposure can cause reversible crystal-to-crystal transition between the PMC and the n-PMC. The PMC exhibits open-close switching of porosity as well as on-off switching of luminescence.

Room-Temperature Activation of the C-H Bond in Methane over Terminal Zn-Oxyl Species in an MFI Zeolite: A Combined Spectroscopic and Computational Study of the Reactive Frontier Molecular Orbitals and Their Origins.

Oxygenase reactivity toward selective partial oxidation of CH to CHOH requires an atomic oxygen-radical bound to metal (M-O: oxyl intermediate) that is capable of abstracting an H atom from the significantly strong C-H bond in CH. Because such a reaction is frequently observed in metal-doped zeolites, it has been recognized that the zeolite provides an environment that stabilizes the M-O intermediate. However, no experimental data of M-O have so far been discovered in the zeolite; thus, little is known about the correlation among the state of M-O, its reactivity for CH, and the nature of the zeolite environment.

As-Heteropentacenes: An Experimental and Computational Study on a Novel Class of Heteroacenes.

Arsenic-containing heteropentacenes were synthesized for the first time; bibenzofuran, benzothienyl benzofuran, and bibenzothiophene were bridged by arsenic atoms. Their structures and properties were experimentally and computationally studied using X-ray crystallography, optical and electronic properties, aromaticity, charge carrier mobility, etc. The present findings on the novel class of heteroacenes will expand functional organic chemistry.

Development of an external-to-internal convertible endoscopic biliary drainage device - a preliminary prospective feasibility study.

Background And Study Aims:  Endoscopic nasobiliary drainage (ENBD) for a malignant stricture in the bile duct has some advantages over endoscopic biliary stenting (EBS). However, ENBD may cause nasopharyngeal discomfort. We developed an external-to-internal convertible endoscopic biliary drainage (ETI-EBD) device that enables both internal and external drainage to occur during a single endoscopy.

An antiparallel double-stranded BODIPY-porphyrin dyad assembled via a self-complementary B-FZn interaction.

An antiparallel double-strand of a BODIPY-zinc-porphyrin dyad was assembled via geometrical complementarity of an unusual B-FZn coordination bonding interaction.

Why do zeolites induce an unprecedented electronic state on exchanged metal ions?

Understanding the exact position and the detailed role of the Al array in zeolites is essential for elucidating the origin of unique properties that can be derived from the metal-ion exchanged in zeolite samples and for designing zeolite materials with high efficiency in catalytic and adsorption processes. In this work, we investigate, for the first time, the important role of the Al array in the reactivity observed on the metal-ion exchanged in zeolites on the basis of the calculation method by utilizing the spontaneous heterolytic cleavage of H observed experimentally on the Zn-ion exchanged in MFI-type zeolites (Zn-MFI) as the model reaction. In the case of calculation, two main types of models for considering the Al positions in MFI-type zeolites were adopted: in the first type, the Al atoms with appropriate distances are aligned in the circumferential direction of the straight channel (abbreviated as a circumferentially arrayed Al-Al site); in the second type, the nearest neighbouring Al atoms with appropriate distances are directed toward the straight channel axis (abbreviated as a channel directionally arrayed Al-Al site).

Importance of the alignment of polar π conjugated molecules inside carbon nanotubes in determining second-order non-linear optical properties.

We employed density functional theory (DFT) calculations with dispersion corrections to investigate energetically preferred alignments of certain p,p'-dimethylaminonitrostilbene (DANS) molecules inside an armchair (m,m) carbon nanotube (n × DANS@(m,m)), where the number of inner molecules (n) is no greater than 3. Here, three types of alignments of DANS are considered: a linear alignment in a parallel fashion and stacking alignments in parallel and antiparallel fashions. According to DFT calculations, a threshold tube diameter for containing DANS molecules in linear or stacking alignments was found to be approximately 1.

Identification of a Stable Zn -Oxyl Species Produced in an MFI Zeolite and Its Reversible Reactivity with O at Room Temperature.

Although a terminal oxyl species bound to certain metal ions is believed to be the intermediate for various oxidation reactions, such as O-O bond generation in photosystem II (PSII), such systems have not been characterized. Herein, we report a stable Zn -oxyl species induced by an MFI-type zeolite lattice and its reversible reactivity with O at room temperature. Its intriguing characteristics were confirmed by in situ spectroscopic studies in combination with quantum-chemical calculations, namely analyses of the vibronic Franck-Condon progressions and the ESR signal features of both Zn -oxyl and Zn -ozonide species formed during this reversible process.

Control of aurophilic interaction: conformations and electronic structures of one-dimensional supramolecular architectures.

Gold(i) chloride complexes with the diarsenic ligands cis-1,4-dihydro-1,4-diarsinines (cis-DHDAs) were synthesized. X-ray diffraction revealed that they formed one-dimensional polymeric structures through aurophilic interactions. Their higher-ordered structures are controlled by the ligand structure; methyl- and t-butyl substituted ligands offered transoid-transoid and transoid-cisoid conformations, respectively.

One-dimensional nanowires of pseudoboehmite (aluminum oxyhydroxide γ-AlOOH).

We report the discovery of a 1D crystalline structure of aluminum oxyhydroxide. It was found in a commercial product of fibrous pseudoboehmite (PB), γ-AlOOH, synthesized easily with low cost. The thinnest fiber found was a ribbon-like structure of only two layers of an Al-O octahedral double sheet having a submicrometer length along its c axis and 0.

Major Increases between Pre- and Post-breakfast Glucose Levels May Predict Nocturnal Hypoglycemia in Type 2 Diabetes.

Objective The aim of this study was to determine whether nocturnal hypoglycemia may be predicted according to morning glucose levels. Methods We retrospectively evaluated 106 patients with type 2 diabetes who underwent continuous glucose monitoring during admission. The pre-breakfast glucose level (Pre-breakfast level), highest postprandial glucose level within 3 hours after breakfast (Highest level), time from the start of breakfast to the highest postprandial glucose level (Highest time), difference between the pre-breakfast and highest postprandial breakfast glucose levels (Increase), area under the glucose curve (≥180 mg/dL) within 3 hours after breakfast (Morning AUC), post-breakfast glucose gradient (Gradient), and the increase-to-pre-breakfast ratio (Increase/Pre-breakfast) were calculated.

Group 14 Dithienometallole-Linked Ethynylene-Conjugated Porphyrin Dimers.

The considerably conjugated π systems of the group 14 dithienometallole-linked ethynylene-conjugated porphyrin dimers (1Ms) were described based on comprehensive experimental and theoretical studies. The electronic absorption spectra of 1M displayed a large splitting in the Soret band and a red-shifted Q-band, indicating that the dithienometallole spacer was effective in facilitating the porphyrin-porphyrin electronic coupling. Torsional planarization behaviors of 1M were observed in the time-resolved fluorescence spectra.

Hypoglycemia and glycemic variability are associated with mortality in non-intensive care unit hospitalized infectious disease patients with diabetes mellitus.

Aims/introduction: We aimed to identify factors - glycemic control, reactive inflammatory biomarkers or vital signs - associated with mortality in diabetic patients admitted to hospital for various infections (non-intensive care unit).

Materials And Methods: We retrospectively analyzed the cases of 620 diabetic patients admitted to hospital for various infections (non-intensive care unit) who underwent glucose monitoring >3 times per day. We extracted data regarding reactive inflammatory biomarkers and vital signs recorded on day 1 of hospital stay, and data on bacteremia and hypoglycemia status, glycemic variability (GV; coefficient of variation and standard deviation) and mean glucose concentrations during the entire hospital stay.