Glucose recognition by a supramolecular complex of boronic acid fluorophore with boronic acid-modified cyclodextrin in water

A boronic acid fluorophore (C1-APB)/boronic acid-modified γ-cyclodextrin (3-PB-γ-CyD) complex as a supramolecular sensor has been designed for selective glucose recognition in water. The fluorescent response behavior of the C1-APB/3-PB-γ-CyD complex under various pH conditions revealed that a C1-APB/3-PB-γ-CyD complex solution containing glucose showed a large increase in the fluorescence intensity under alkaline pH conditions. In contrast, only small increases in the fluorescence intensity were noted for fructose and without sugar solutions. The observed response selectivity for the C1-APB/3-PB-γ-CyD complex was on the order of glucose > galactose, mannose > fructose. The evidence on a large value of the inclusion constant (K(L·CyD) = 6.5 × 10(3) M(-1)), a marked broadening of the (1)H NMR spectra, and an enhancement of induced circular dichloism (ICD) intensity for the C1-APB/3-PB-γ-CyD complex by glucose binding supported the multi-point interaction of the C1-APB/3-PB-γ-CyD complex with glucose. These results demonstrated that the C1-APB/3-PB-γ-CyD complex functioned as an efficient supramolecular sensor for selective glucose recognition in water.     

Imination of Sulfides and Sulfoxides with Sulfonylimino‐λ3‐Bromane under Mild,Metal‐Free Conditions

Exposure of sulfides and sulfoxides to trifluoromethanesulfonylimino(aryl)‐λ³‐bromane in dichloromethane at 0 °C results in a facile transfer of the sulfonylimino group to sulfur atoms and affords N‐triflylsulfilimines and ‐sulfoximines in high yields under transition‐metal‐free conditions. Imination of (R)‐methyl p‐tolyl sulfoxide proceeded with predominant retention of configuration at the stereogenic sulfur center. The Hammett plot afforded ρ values of ?0.58 for para‐substituted thioanisoles and ?0.49 for their equivalent sulfoxides, which suggests a buildup of positive charge on the sulfur atoms of sulfides and sulfoxides in the transition state. Calculations suggest a bimolecular nucleophilic‐substitution mechanism on the negatively charged nitrogen atom of the sulfonylimino‐λ³‐bromane, which involves the attack of a sulfide from the opposite side to bromine(III).     

Excess enthalpies of binary mixtures of <Emphasis Type="Italic">ortho</Emphasis>-, <Emphasis Type="Italic">meta</Emphasis>-, <Emphasis Type="Italic">para</Emphasis>-structural isomers containing aliphatic group

To obtain further systematic information for the isomer systems, the excess molar enthalpies for binary (o + m), (o + p), (m + p)-isomers of methoxymethylbenzene, ethylmethylbenzene, diethylbenzene, chloromethylbenzene, tolunitrile and fluorobenzonitrile, tolylacetonitrile were measured at 298.15 K. In this article, the results are discussed and compared with those of previous works. The excess enthalpies of binary systems in different solid and liquid states were measured when the pure component of o-/m-tolunitrile, fluorobenzonitrile was titrated into the prior (o + p) or (m + p) mixtures. A series calculation for the interaction energies (IE) between the isomers was carried out for the pair molecules by ab initio MO of Gaussian 09. Correlations between the excess enthalpies at a molar fraction of x = 0.5 and the intermolecular energy are discussed.     

Orlicz–Morrey Spaces and Fractional Operators

By taking an interest in a natural extension to the small parameters of the trace inequality for Morrey spaces, Orlicz–Morrey spaces are introduced and some inequalities for generalized fractional integral operators on Orlicz–Morrey spaces are established. The local boundedness property of the Orlicz maximal operators is investigated and some Morrey-norm equivalences are also verified. The result obtained here sharpens the one in our earlier papers.     

A capacity scaling algorithm for M-convex submodular flow

This paper presents a faster algorithm for the M-convex submodular flow problem, which is a generalization of the minimum-cost flow problem with an M-convex cost function for the flow-boundary, where an M-convex function is a nonlinear nonseparable discrete convex function on integer points. The algorithm extends the capacity scaling approach for the submodular flow problem by Fleischer, Iwata and McCormick (2002) with the aid of a novel technique of changing the potential by solving maximum submodular flow problems.Mathematics Subject Classification (1991): 90C27A preliminary version of this paper has appeared in Proceedings of the Tenth International Conference on Integer Programming and Combinatorial Optimization (IPCO X), LNCS 3064, Springer-Verlag, 2004, pp. 352–367.     

Extended Hypervalent 5c–6e Interactions: Linear Alignment of Five C─Z- - -O- - -Z─C (Z = S,Se) Atoms in Anthraquinone and Anthracene Systems

Abstract

Structures of 1,8-(ArZ)₂C₁₄H₆O₂ and 9-(MeO)-1,8-(ArZ)₂C₁₄H₇ (Z = S, Se) are determined by X-ray crystallographic analysis. Five C─Z- - -O- - -Z─C atoms of the compounds align linearly, which are analyzed by the extended hypervalent 5c–6e model, based on QC calculations. CT of the 5c–6e occurs as the σ^*(C─Z) ← n _p (O)→ σ*(Z─C) direction.     

Effect of carboxyl group on the visible-light photocatalytic activity of SrTiO3 nanoparticles

SrTiO₃ nanoparticles modified with a carboxyl group were successfully prepared by microwave-assisted solvothermal reaction of SrCl₂·6H₂O and Ti(OC₃H₇)₄ in methanol–organic acid solution. The as-prepared products were characterized using X-ray diffraction (XRD), diffuse reflectance spectroscopy, and Fourier-transform infrared (FTIR) spectroscopy. The photocatalytic activity was determined by DeNO _x ability using a mercury arc with filters to control irradiation wavelengths to >290, >400, and >510 nm. Nanoparticles of perovskite-type SrTiO₃ were successfully synthesized above pH 12. The photocatalytic activity of SrTiO₃ under visible-light (>510 nm) irradiation could be promoted by surface modification of SrTiO₃ with the carboxyl group (–COO), especially from oleic acid.     

Ion conductive characteristics of DNA containing PEO chains covalently bound on nucleic acid bases

In order to prepare flexible and ion conductive deoxyribonucleic acid (DNA) films without phase separation, DNA was modified with poly(ethylene oxide) (PEO). PEOs with molecular weight of 150 to 2000 were fixed to the amino groups of nucleic acid bases in DNA (PEO‐DNA). Brittle DNA films turned flexible after PEO modification, and the highest ionic conductivity was obtained when PEO with molecular weight of 1000 was modified. Though Na⁺, counter cation of phosphate group, was expected to migrate in these PEO_x‐DNA hybrids as a carrier ion, ionic conductivity was only 1.3 × 10^?6 S cm^?1. Addition of salts to PEO₁₀₀₀‐DNA considerably improved the ionic conductivity, and sodium bis(trifluoromethanesulfonyl)imide (NaTFSI) was the best salt for this purpose. When NaTFSI, 5 mol% to the oxyethylene (OE) unit, was mixed with PEO₁₀₀₀‐DNA, the highest ionic conductivity of 1.77 × 10^?5 S cm^?1 was observed at 30°C. Copyright © 2004 John Wiley & Sons, Ltd.     

Synthesis, structural, spectroscopic and electrochemical studies of carborane substituted naphthyl selenides

New unsymmetrical selenides bearing an o-carborane and a naphthalene ring as the substituents were prepared by the cleavage of the corresponding diselenides. The compounds were characterized by means of spectroscopic and analytical methods. (77)Se NMR signals of the selenium atoms attached to the carbon atoms of the carborane cages are shifted downfield in comparison to those bonded only to the aromatic rings, indicating an electron withdrawing effect of the o-carboranyl substituent. Compounds 1-(2-R-1,2-dicarba-closo-carboranyl)naphthyl selenides (R = Me, 1; Ph, 2) were characterized by means of single crystal X-ray diffraction. The influence of the electronic nature of the substituents attached to the selenium atoms on the structural parameters and packing properties of naphthyl selenides are discussed. Theoretical calculations and cyclic voltammetry (CV) studies were carried out to compare the bonding nature of carboranyl and analogous aryl selenium compounds. Cyclic voltammetry studies of naphthyl carboranyl mono and diselenides have shown that the carboranyl fragment polarizes the Se lone pair making it less prone to generate a Se-Se bond.     

Synthesis and catalytic properties of 4-aryl-2,3-dihydro-4H-pyrimido[2,3-b]benzothiazoles for asymmetric acyl or carboxyl group transfer reactions

4-Aryl-2,3-dihydro-4H-pyrimido[2,3-b]benzothiazoles (4-Ar-DHPBs) were synthesized and their catalytic activity and selectivity in kinetic resolution of a secondary alcohol as well as in the Steglich rearrangement and related reactions were evaluated. 4-Aryl-DHPBs showed low enantioselectivity in the acylative kinetic resolution of 1-phenylethanol. Conversely, they catalyzed the Steglich rearrangement with moderate to excellent enantioselectivity, demonstrating the possibility for remote stereocontrol by introduction of a substituent at the 4-position of DHPB.