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Thiophene–thiophene copolymers composed of 3-alkylthiophene and a small amount of thiophene bearing cyclic siloxane are synthesized by random copolymerizatin of 2-chloro-3-dodecylthiophene and 2-chlorothiophene bearing cyclic tetrasiloxane as a substituent. Deprotonative metalation of chlorothiophenes with a bulky magnesium amide followed by the addition of nickel catalyst undergoes polymerization to afford statistical copolymer based on the feed ratio. The copolymer bearing a small amount of (1–10%) cyclic siloxane is subjected to the formation of thin film. The treatment of the obtained thin film with an acid vapor results in the formation of film insoluble in any solvent through the formal networking of poly(3-dodecylthiophene) by the effect of a small amount of cyclic siloxane moiety. The measurement of electric properties reveals improved conductivities to 10(6) fold higher than before the acid treatment.

The synthesis of 1,1-difluoro-1-alkenes was achieved by the treatment of dithioesters and thioketones with trimethylsilyl 2-fluorosulfonyl-2,2-difluoroacetate in the presence of a proton sponge cat...

The low dielectric constants of organic semiconductors, relative to those of inorganic materials, are an intrinsic limitation. Improving the dielectric constant is important for the development of ...

This article reports production protocols for nanographenes and the effect of the reaction conditions on their structures and optical properties. These fundamental studies are of value for explorin...

This account highlights the development of efficient methods for generation of alkyl radicals from organosilicon peroxides and their applications in selective alkylation reactions. Compared with co...

The selective reduction of α,β-unsaturated carbonyl compounds was achieved to produce saturated carbonyl compounds with aqueous HI solution. The introduction of an aryl group at an α or β position ...

Graphene nanoribbons (GNRs), which are narrow and elongated strips of graphene, enable the formation of a more interconnected pore structure than two-dimensional graphenes. In this work, hydrated G...

The new and versatile method for the synthesis of integrastatin core has been developed by the use of o-toluic acid and 2′-hydroxyacetophenone with NaH/sec-BuLi, followed by the reaction of dihydro...

An isolated cluster of 32 ammonia (NH3) molecules was simulated at 50 and 100 K by the ab initio fragment molecular orbital based molecular dynamics (FMO-MD) method to analyze the effect of electro...

The versatility of the synthesis of sulfonated aromatic polymers using NiBr2 was investigated. The copolymerization of sulfo-dichlorobenzene protected with a neopentyl group was carried out with ch...

Hydrogen adsorption/desorption properties of magnesium oxalate and calcium oxalate (M(ox); M = Mg2+ and Ca2+) were measured at selected temperatures between 77 K and 200 K. The hydrogen uptake amou...

In this study, the hydrolytic condensation of 3-(2-aminoethylamino)propyltrimethoxysilane and 3-aminopropyltrimethoxysilane was performed using aqueous trifluoromethanesulfonic acid (HOTf) as a cat...

Absorption properties of 13 bisazomethine dyes in a crystalline state were studied by optical waveguide spectroscopy. Their solid-state absorption spectra were found to shift bathocromically relative to those in solution with no remarkable change in a spectral shape. The observed spectral shifts were characterized in terms of two intermolecular interactions, conformational change and exciton interaction, on the basis of the crystal structure. Solid-state fluorescence properties of the diethylamino derivatives were also examined for their electronic characterization. The characteristic two-dimensional staircase structure, one of the proposed structures of J-aggregates, was found to play a significant role in the bathochromic spectral shift of all the bisazomethine derivatives.

Dehydration and rehydration behavior of a layered double hydroxide (LDH), Mg2Al(OH)6.2Cl0.8·nH2O, was investigated. The dehydration proceeds in two steps; at first interlayer water is released from 50 °C, then dehydration condensation of hydroxyl groups starts from 300 °C. Interlayer anion Cl− is also desorbed as HCl during the second dehydration. The mole fraction of water removed by dehydration before the HCl desorption was estimated by thermogravimetric analysis; 1.85 mol-H2O/mol-LDH. The dehydrated material, without HCl loss, was quantitatively hydrated by refluxing in water for 480 min.

This article describes the full details of our reductive approach to nitrones from amides. Reduction of N-siloxyamides with the Schwartz reagent [Cp2ZrHCl], followed by addition of an acid provided functionalized nitrones. The developed conditions were then extended to a catalytic version with the Vaska complex [IrCl(CO)(PPh3)2] and (Me2HSi)2O starting from N-hydroxyamides. 1H NMR studies of the Ir-catalyzed reaction revealed that the developed conditions promoted two different types of catalytic reactions including dehydrosilylation of an N-hydroxyl group and subsequent hydrosilylation of an amide carbonyl. A salient feature of our methods is their high chemoselectivity in the presence of a variety of functional groups. In addition, our reductive methods enabled concise synthesis of cyclic and macrocyclic nitrones, which are known to be challenging compounds to access by conventional methods.

The structure and electronic features of neutral and positively charged pyrene and perylene derivatives were explored. The radical cation of 1,3,6,8-tetraarylpyrene 1 was examined by ESR, UV-vis-NIR spectroscopy and theoretical calculations. The addition of 2 equiv of oxidant to 1 resulted in the formation of dication 12+. The single-crystal X-ray structure of 12+ proved that the aromatic part relocates from biphenyl unit to naphthyl unit upon 2e- oxidation of 1. We have also investigated the oxidation processes of 3,9-diarylperylene 2 and 3,10-diarylperylene 3. The radical cations of 2・+ and 3・+ showed ESR signals and the spin densities were proven to delocalize at 3,4,9,10-positions. In the case of doubly charged 3,9-diarylperylene, we could find the anthracene structure in the core, while the phenanthrene skeleton appeared in two-electron oxidized 3,10-diarylperylene. Finally we validated this phenomenon to apply for the higher analogue terrylene, discovering its large aromaticity relocation upon the 2e- oxidation.

We investigated stable radical distribution and particle tracks in sucrose irradiated by C ion irradiation with continuous wave (CW) electron paramagnetic resonance (EPR) and 9 GHz EPR imaging. Both EPR results were compared with X–ray irradiation at a similar dose. Radical distribution in sucrose crystals induced by C ion and X–ray irradiation were completely different. The 2D EPR imaging results suggested that radical species were mostly located inside the sucrose crystal. Fewer radicals were found on the surface region of the sucrose crystal. The high radical intensities in relation to the C ion energy deposition are clearly observed at Bragg peak region. No trace of the stable radicals was found after the peak region. The stable radicals of sucrose were distributed as results of recombination of radicals induced by particle interaction. For the first time, the present EPR images showed the stable radical distribution and particle tracks in the crystal in association with particle-sucrose interaction.

Much interest has been paid to the origin of homochirality, such as that of l-amino acids. The proposed origins of chirality have usually induced only low enantiomeric excess. Thus, asymmetric amplification by asymmetric autocatalysis has been invoked. Asymmetric autocatalysis of 5-pyrimidyl alkanol in the enantioselective addition of diisopropylzinc to pyrimidine-5-carbaldehyde is a unique example of amplification of chirality. Crystallization of possible intermediates, specifically zinc alkoxides of this 5-pyrimidyl alkanol, was investigated to obtain mechanistic insights into this reaction. Single-crystal X-ray crystallography of the formed zinc alkoxide crystals shows the existence of tetramer or higher oligomer structures in this asymmetric autocatalytic system.

Pigments in the printing inks employed for Japanese hand-engraved stamps, the first issues of Japanese postage stamps, were analyzed and characterized by means of FTIR, Raman, and XRF spectroscopy....

We examined intermolecular hydrogen-bonding interactions of pyrene derivatives bearing a urea unit, referred to as 1PUP (one pyrenyl group) and 1DPU (two pyrenyl groups). 1DPU showed a new emission...

Optical properties of three crystal modifications of 5-t-butyl-2,3-dicyano-6-[4-(dimethylamino)styryl]pyrazine having different color appearances were measured and interpreted on the basis of crystal structure analysis. Two of the three modifications exhibited a bathochromic spectral shift both in absorption and fluorescence compared with those in a toluene solution of the dye. The crystal structure analysis revealed that a two-dimensional brick-wall structure is formed in both modifications. In contrast, the third modification showed a hypsochromic absorption shift with a large bathochromic fluorescence shift. The crystal structure of this modification was characterized by a one-dimensional stacked molecular column. The optical characteristics of the three modifications were qualitatively interpreted in terms of excitonic intermolecular interaction on the basis of their crystal structures.

The reactions of [MoII2(OAc)4] (OAc−: acetato) with catecholato derivatives (R-Cat2−), possessing electron-donating t-Bu groups (3,6-DTBCat2−) or electron-withdrawing Br groups (Br4Cat2−), results ...

[60]Fullerene assembly films consisting of C60 and 1,2-diaminoethane (ethylenediamine) were easily fabricated on an amino-group-modified substrate by an alternate immersion process. The C60-assembl...

Organic electron-accepting materials with light absorbance and wide absorption bands are sorely needed as alternatives to fullerene derivatives for organic electronics, in particular for organic ph...

Much attention has been paid to water-soluble porphyrins and metalloporphyrins as potential sensitizers for photodynamic therapy (PDT). Thus, water-soluble tricationic phosphorus porphyrin complexe...

The electrochemical activities of binary metals in a Pd–Nb system were investigated as a function of their compositions, crystal structures, using a hydrogen peroxide and ascorbic acid redox reacti...

The photocatalytic H2 evolution by Pt-loaded TiO2 was examined using sacrificial agents such as 1,2-ethanediol, glycerol, erythritol, and arabitol, the carbons of which all have hydroxy groups. In ...

A monoclonal antibody (mAb) specific to triacetone triperoxide (TATP) was produced from the stable hybridoma cell line 15B-1E, generated by the fusion of myeloma cells with spleen cells isolated fr...

The kinetics for the reaction of the 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical with artepillin C, a prenylated phenylpropanoid found specifically in Brazilian propolis, and its analogues was examined in deaerated acetonitrile (MeCN) to shed light on the mechanism for the radical-scavenging reaction of phenolic antioxidants as well as on the structure-activity relationship. Among the examined analogues, a compound having a catechol moiety is found to have the largest second-order rate constant (k) for the DPPH radical-scavenging reaction. The deuterium kinetic isotope effect of 1.6 was observed for the DPPH radical-scavenging reaction of artepillin C in the presence of 0.13 M CD(3)OD or CH(3)OH in deaerated MeCN at 298 K. The log k values were found to be linearly correlated with calculated energy difference values (D(HT), HT = hydrogen transfer) between the artepillin C analogues and the corresponding phenoxyl radicals, while such a linear correlation cannot be observed between the log k values and calculated ionization potentials (IP), D(HT) - IP, or experimental one-electron oxidation potentials of the artepillin C analogues. These results together with a calculated structure of the transition state for the reaction between the artepillin C analogue and the DPPH radical suggest that the DPPH radical-scavenging reaction of the artepillin C analogues in deaerated MeCN proceeds via a one-step hydrogen-atom transfer from the phenolic OH group to the DPPH radical rather than an electron transfer followed by proton transfer.

Three SmIII complexes with tripod heptadentate N7 ligands containing three imidazole groups, [Sm(H3L2-Me)(ac)](ClO4)2·2MeOH·H2O (1), [Sm(H3L2-Me)(ac)](ClO4)2·2EtOH (2), and [Sm(H3L4-Me)(ac)](ClO4)2...

A 2D iron(II) spin-crossover (SCO) complex, [FeII(HLH,Me)2](CF3SO3)2, was synthesized, where HLH,Me: 8-(imidazol-4-ylmethylideneamino)-2-methylquinoline, and its structures and magnetic properties ...

Photoluminescence properties of TiO (Ti1.825O4) and NbO (Nb6O17) nanosheets adsorbed with Ln3+ ions were studied comparing with those of photoluminescent Gd–Eu–Ti–O and La–Tb–Ta–O perovskite nanosh...

A low-spin FeIII complex, [FeIII(H2L5-Me)(HL5-Me)](ClO4)2·EtOH, was prepared by the reaction of FeII(ClO4)2·6H2O and H2L5-Me in ethanol with 1:2 molar ratio and in air, where H2L5-Me: N-[(5-methyli...

Proton conductivity of graphene oxide (GO) has been reduced in graphene oxide–metal ion hybrids (GO–M; M = K+, Al3+, Zn2+, Fe3+, Cr3+, Co2+, Pr3+, Ce3+, and Tb3+). As the hybrids contain doped meta...

Three copper(II)–gadolinium(III) complexes M[Gd(CuL)4] with M+ = Na+, K+, and Cs+ have been synthesized, where H3L denotes N-(4-methyl-6-oxo-3-azahept-4-enyl)oxamic acid. The anionic part [Gd(CuL)4...

A mixture of sodium 1,2-di(hexadecyloxycarbonyl)ethanesulfonate (2C16S) with photopolymerizable 1,2-di(10,12-tricosadiynoyl)-sn-glycerol 3-phosphocholine (DTPC) in a 2:100 ratio was treated by modi...

Metachromatic staining with toluidine blue (TB) has been used as a cytological too lf or tissue recognition and cancer diagnosis. Recently, its strong potentia lf or infertility diagnosis was also reported. Metachromatic staining is important i nb iological applications, but the origi no f spectral changes has not been fully understood, although dye aggregation on biological materials is thought to be the cause. In this study, we investigated the dimer structure of TB formed on DNA oligomers by using a computational method, particularly focusing on the spectral changes caused by TB dimer formation. The structure of the TB­DNA complexes was constructed on the basi so f the calculated molecular structure of TB and crystal data of A- and B-form DNA oligomers, assuming that there was an electrostatic interaction between them. The resulting spectral shift was then evaluated using the extended-dipole model. The examination of B-DNA revealed that possibl eT B dimers result in a hypsochromic spectral shif to f absorption. On the other hand, the dimerization of TB on A-DNA was found to be quite difficult, because the helical geometry of A-DNA restricted the binding sites of TB. These results suggest that the metachromati cc olor observed during biological staining i ss ignificantly affected by the helical geometry of DNA.

The enzyme-mediated enantioselective hydrolysis of middle molecular weight poly(ethylene glycol) (PEG)-supported carbonates is disclosed. The representative water-soluble substrate was prepared by ...

The stereocenter in the intermediate alcohol (86% ee), created by enantioselective oxazaborolidinone-promoted aldol reaction, was transferred to the stereocenter in the cyclohexanone ring, necessar...

Mononuclear [Fe(H2L2-Et-5-Me)2]2+ and dinuclear [Fe2(H2L2-Et-5-Me)3]4+ complexes, where H2L2-Et-5-Me denotes 2-ethyl-5-methylimidazole-4-carbaldehyde azine, were prepared and isolated as the perchl...

Copper(II) complexes with tridentate ligands H2LR (R = H, 2-Me, and 5-Me) derived from 1:1 condensation products of DL-phenylalanine and imidazole-4-carbaldehyde derivatives (imidazole-4-carbaldehy...

A mononuclear copper(II) complex, [2-ethoxy-6-{[3-(2-methyl-4-imidazolylmethyleneamino)propyl]iminomethyl}phenolato]copper(II) perchlorate [CuHL]ClO4 and its deprotonated complex at the imidazole m...

o-Hydroxybenzophenone (Hbp) chromophores were immobilized on 3-aminopropyl silica gel (SiO 2 -NH 2 ) by a reaction of succinimidyl 4-(4-benzoyl-3-hydroxyphenoxy)butanoate (2a) and -undecanoate (2b) with SiO 2 -NH 2 to produce microbeads 1a and 1b in 25 and 21% yield, respectively. The bond formation was confirmed by appearance of an absorption at 1550 cm -1 due to the N-H bending of the amide bond in the IR spectra of 1a and 1b. In order to enhance the thermal and photochemical stabilities, the 1a and 1b residual amino group was acetylated by Ac 2 O in CHCl 3 to produce 7a and 7b. Acetylation occurred on the aminopropyl group. However, it did not occur on the phenolic OH group of Hbp from the IR spectra where the absorptions of the bending of the methyl group and the bending of the phenolic OH group appeared at 1375 and 1348 cm -1 , respectively. By degradation experiments, it was found that thermal and photochemical stabilities were high in 7a and 7b compared with that of 1a and 1b.

N2 yield on Ba0.8La0.2Mn0.8Mg0.2O3 decreased from 70% to 30% on the addition of 1% CO2, which is a much larger negative effect than that seen with O2. The CO2 negative effects are not permanent and...

Heterotrinuclear [(NiIIL)2LnIII(NO3)] complexes (where H3L = 1,1,1-tris[(salicylideneamino)methyl]ethane and Ln = Gd (1), Eu (2), Tb (3), and Dy (4)) were prepared by treating [Ni(H1.5L)]Cl0.5 with...

We investigated the effects of an axial amino ligand on the spectroscopic and electrochemical properties of alkylamino(methoxo)(tetraphenylporphyrinato)antimony(V) bromide 1 and anilino(methoxo)(te...

The role of adsorption species in reaction solutions has been studied in microwave-polyol synthesis of silver (Ag) nanostructures. When Ag+ ions from AgNO3 were reduced in ethylene glycol by the addition of H2[PtCl6] and poly-(vinylpyrrolidone) (PVP), a mixture of one-dimensional (1-D) nanorods and nanowires and 3-D spherical, cubic, and triangular-bipyramidal nanoparticles was obtained within three minutes. It has been previously believed that PVP acts as a surfactant and its selective adsorption on {100} facets results in pentagonal 1-D nanorods or nanowires and cubic and triangular-bipyramidal nanocrystals. We found here that these Ag products could also be formed without the addition of PVP in the presence of Cl- ions, though their yields were lower than those in the presence of PVP by a factor of ˜300. These results indicate that Cl- anions can also act as adsorption species to assist the formation of these Ag nanostructures. It is concluded that the difference in the adsorption ability of different species in solution on Ag nanostructures determines final shapes, sizes, and yields of formed Ag nanostructures.