Structure and photoluminescence property of two-dimensional coordination polymer complexes involving Cu(I)(6)X(6)(X = Cl, Br, I) hexagon prism cluster supported by a tripodal tripyridine ligand with 1,3,5-triethylbenzene spacer

Treatment of cuprous halide (Cu(I)X, X = Cl, Br, and I) and a tripodal tripyridine ligand (L) consisting of a 1,3,5-triethylbenzene spacer gave a unique two-dimensional (2D) polymer sheet structure involving a rare Cu(I)(6)X(6) hexagon prism cluster unit, which exhibits intense fluorescence around 448-476 nm.     

Dipole interaction-controlled stereoselectivity in aldol reaction of alpha-CF3 enolate with fluoral

The stereoselectivity of a reaction is generally determined by minimizing steric repulsion. However, the aldol reaction of alpha-CF(3)-ketone (Z)-enolate with fluoral anomalously gave an anti-aldol through a sterically demanding transition state, because of the strong dipole interaction of the two CF(3) groups. We have thus disclosed a paradigm shift from steric to electronic control of reaction stereoselectivity. [reaction: see text]     

Vinyliodonium salts : their stereospecific synthesis and reactions as the activated vinyl halides

Vinyliodonium salts $\text{2}$ were synthesized from vinylsilanes $\text{1}$ by the reaction with iodosylbenzene and triethyloxonium tetrafluoroborate. The reaction occurs stereospecifically with retention of configuration. Vinyliodonium salts $\text{2}$ are highly effective as the activated species of vinyl iodides. Thus, a variety of substituted olefins including α-cyano and α-nitro olefins, vinyl sulfides, vinyl halides, and α,β-unsaturated esters, were prepared from $\text{2}$ under mild reaction conditions.     

Encapsulation of titanium(IV) oxide particles in hollow silica for size-selective photocatalytic reactions

A core-shell composite of TiO2 particles encapsulated in a hollow silica was fabricated, and the core-shell composite showed size-selective photocatalytic activity for decomposition of organics without reducing the intrinsic activity of the naked TiO2 core.     

A pregnane glycoside from overripe tomato

A new pregnane glycoside, 3-O-beta-lycotetraosyl 5alpha-pregna-3beta,26beta-diol-20-one was isolated from overripe tomato, the fruit of Lycopersicon esculentum MILL.     

Synthesis of New Quinolone Antibiotics Utilizing Azetidine Derivatives Obtained from 1-Azabicyclo[1.1.0]butane

A series of 3-sulfenylazetidine derivatives 5a-f were synthesized via the ring-opening reactions of 1-azabicyclo[1.1.0]butane (ABB, 3) with thiols 4a-f in 50-92% yields. Treatment of ABB (3) with aromatic amines 9a-e and dibenzylamine (9f) in the presence of Mg(ClO4)2 afforded the corresponding 3-aminoazetidine derivatives 10a-f in 24-65% yields. N-Benzyl-3-bromoazetidine (13), which was obtained by the reaction of ABB (3) with benzyl bromide, gave 3-aliphatic amino-substituted azetidine derivatives 15a, b. Novel fluoroquinolones 7a-f, 11a-f, 16a, b and 25a-c were obtained by the introduction of these azetidine derivatives into the C7 position of a quinolone nucleus 6 and N1-heterocyclic quinolones 21a-c in 21-83% yields. Some of them exhibited a greater antibacterial activity against methicillin-resistant Staphylococcus aureus (MRSA) in comparison with that of clinically used fluoroquinolone, levofloxacin (LVFX).     

Isomeric effect of sulfonated poly(arylene ether)s comprising dihydroxynaphthalene on properties for polymer electrolyte membranes

Polymer electrolyte membranes (PEMs) made of sulfonated poly(arylene ether)s consisted of 3,3′‐disulfo‐4,4′‐dichlorodiphenylsulfone disodium salt, 2,6‐dichlorobenzonitrile, and one of three dihydroxynaphthalene isomers (2,6‐, 2,7‐, and 1,5‐dihydroxynaphthalene, abbreviated as 2,6‐N, 2,7‐N, and 1,5‐N, respectively) were prepared with similar level of inherent viscosity and ion exchange capacity, and structural effect of the catenation in dihydroxynaphthalene isomers on membrane properties was compared. In the case of membranes for PEM fuel cell application with relatively high ion exchange capacity around 2.1 mequiv/g, three copolymers showed almost the same proton conductivity; however, swelling in water increased with the following order: 1,5‐N < 2,6‐N < 2,7N. In the case of direct methanol fuel cell membranes with lower ion exchange capacity around 1.5 mequiv/g, no remarkable difference in proton conductivity was also observed in three isomeric copolymers and swelling property and methanol permeability were lower in 1,5‐N and 2,6‐N copolymers than 2,7‐N copolymer. These tendencies show that higher rigidity or energy barrier for conformational change of polymer chain gives better performance of PEM for fuel cells with superior dimensional stability. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012     

Mechanochromic Luminescence from Crystals Consisting of Intermolecular Hydrogen‐Bonded Sheets

Introduction of functional groups that can form intermolecular hydrogen bonds into highly‐emissive luminophores is a promising way to induce mechanochromic luminescence. Herein, we report that a 9,10‐bis(phenylethynyl)anthracene derivative featuring two amide groups forms green‐emissive crystals based on two‐dimensional hydrogen‐bonded molecular sheets. Mechanical grinding changed the emission from green to yellow, owing to a transition from a crystalline to an amorphous phase. Infrared spectroscopy revealed that mechanical stimuli disrupted the linear hydrogen‐bonding formation. A thermal treatment recovered the original green photoluminescence.