New Finding of the Glass Transition Phenomenon in Surfactant Gel Phase: The Binary System of Water and Dioctadecyldimethyl-Ammonium Chloride

Differential scanning calorimetry on the two-component system of dioctadecyldimethylammonium chloride (DOAC)–water was carried out in the temperature region from 80 °C down to -100 °C. As the result, a new type of glassy state was found around at -40 °C for the supercooled complete gel phase.     

Two‐Step direct arylation for synthesis of naphthalenediimide‐based conjugated polymer

A naphthalenediimide (NDI)‐based conjugated polymer was synthesized by a two‐step direct C‐H arylation sequence. In the first step, two ethylenedioxythiophene units were coupled to NDI by direct arylation. In the second step, the direct arylation polycondensation of the monomer, formed in the first step, with 2,7‐dibromo‐9,9‐dioctylfluorene afforded the corresponding NDI‐based conjugated polymer ( PEDOTNDIF ) with molecular weight of 21,500 in 91% yield. The optical and electrochemical properties of the polymer were evaluated. The polymer showed ambipolar behavior in organic field‐effect transistors (OFETs). The electron mobility of PEDOTNDIF was estimated to be 2.3 × 10^?6 cm² V^?1 s^?1 using an OFET device with source‐drain (S‐D) Au electrodes. A modified OFET device with S‐D MgAg electrodes increased the electron mobility for PEDOTNDIF to 1.0 × 10^?5 cm² V^?1 s^?1 due to the more suitable work function of these electrodes, which reduced the injection barrier to the semiconducting polymer. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014 , 52, 1401–1407     

Effect of ammonium groups on the properties and alkaline stability of poly(arylene ether)‐based anion exchange membranes

Five kinds of ammonium groups functionalized partially fluorinated poly(arylene ether) block copolymer membranes were prepared for investigating the structure–property relationship as anion exchange membranes (AEMs). Consequently, the pyridine (PYR)‐modified membrane showed the highest alkaline and hydrazine stability in terms of the conductivity, water uptake, and dry weight. The chloromethylated precursor block copolymers were reacted with amines, such as trimethylamine, N‐butyldimethylamine, 1‐methylimidazole, 1,2‐dimethylimidazole, and PYR to provide the target quaternized poly(arylene ether)s. The structures of the polymers, as well as model compounds and oligomers were well characterized by ¹H NMR spectra. The obtained AEMs were subjected to water uptake and hydroxide ion conductivity measurements and stabilities in aqueous alkaline and hydrazine media. The pyridinium‐functionalized quaternized polymers membrane showed the highest alkaline and hydrazine stability with minor losses in the conductivity, water uptake, and dry weight. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014 , 52, 383–389     

Optical properties of highly planar diketopyrrolopyrrole derivatives fixed by coordinate bonds

Diketopyrrolopyrrole (DPP) derivatives bearing 2-pyridyl groups were synthesized, which could serve as anionic N,N′-chelate ligands consisting of two nitrogen atoms of the lactam moieties and the pyridyl groups. Coordination of the DPP ligand to boron and platinum yielded the corresponding DPP complexes. Their crystal structures exhibited coplanar structures between the DPP core and the 2-pyridyl groups, which indicated extended π-conjugation. The maximum absorption wavelength of the DPP complexes was longer than that of the corresponding DPP ligands. The choice of the introduced element affects the optical properties of the DPP complexes; the platinum complex has a longer absorption wavelength than the boron complex. The theoretical calculation revealed that these absorptions can be attributed to the π–π* transition. The introduction of the coordinating elements predominantly lowers the band gap. In addition, the substituent on the 2-pyridyl group can also modulate the energy levels.     

Evaluation of a series of prolylamidepyridines as the chiral derivatization reagents for enantioseparation of carboxylic acids by LC–ESI–MS/MS and the application to human saliva

Mass spectrometry has become a popular analytical tool because of its high sensitivity and specificity. The use of a chiral derivatization reagent for the mass spectrometry (MS) detection seems to be efficient for the enantiomeric separation of racemates. However, the number of chiral reagents for the liquid chromatography (LC)–MS/MS analysis is very limited. According to these observations, we are currently in the process of developing novel labeling reagents for chiral molecules in MS/MS analysis. The derivatization reagent that is effective for enhancing not only the electrospray ionization–MS/MS sensitivity but also the reversed-phase LC resolution of carboxylic acid enantiomers should have a highly proton-affinitive moiety and an asymmetric structure near the reactive functional group. Furthermore, the resulting derivative has to provide a characteristic product ion suitable for the selected reaction monitoring. Based upon these considerations, a series of prolylamidepyridines ((S)-N-pyrrolidine-2-carboxylic acid N-(pyridine-2-yl)amide (PCP2), (S)-N-pyrrolidine-2-carboxylic acid N-(pyridine-3-yl)amide, and (S)-N-pyrrolidine-2-carboxylic acid N-(pyridine-4-yl)amide) was synthesized as ideal labeling reagents for the enantioseparation of chiral carboxylic acids and evaluated in terms of separation efficiency and detection sensitivity by ultra-performance LC (UPLC)–MS/MS. Among the synthesized reagents, PCP2 was the most efficient chiral derivatization reagent for the enantioseparation of carboxylic acid. The Rs values and the detection limits of the derivatives of non-steroidal anti-inflammatory drugs, which were selected as the representative carboxylic acids, were in the range of 2.52–6.07 and 49–260 amol, respectively. The sensitive detection of biological carboxylic acids (detection limits, 32–520 amol) was also carried out by the proposed method using PCP2 and UPLC–MS/MS. The PCP2 was applied to the determination of carboxylic acids in human saliva. Several biological carboxylic acids, such as lactic acid (LA), 3-hydroxybutylic acid, maric acid, succinic acid, α-ketoglutalic acid, and citric acid, were clearly identified in the saliva of healthy persons and diabetic patients. Furthermore, the ratio of d-LA in diabetic patients was higher than that in normal subjects. Judging from these results, PCP2 seems to be a useful chiral derivatization reagent for the determination not only of chiral, but also achiral, carboxylic acids in real samples.

Preparation of Molecule‐Responsive Microsized Hydrogels via Photopolymerization for Smart Microchannel Microvalves

Microdevices designed for practical environmental pollution monitoring need to detect specific pollutants such as dioxins. Bisphenol A (BPA) has been widely used as a monomer for the synthesis of polycarbonate and epoxy resins. However, the recent discovery of its high potential ability to disrupt human endocrine systems has made the development of smart systems and microdevices for its detection and removal necessary. Molecule‐responsive microsized hydrogels with β‐cycrodextrin (β‐CD) as ligands are prepared by photopolymerization using a fluorescence microscope. The molecule‐responsive micro‐hydrogels show ultra‐quick shrinkage in response to target BPA. Furthermore, the flow rate of a microchannel is autonomously regulated by the molecule‐responsive shrinking of their hydrogels as smart microvalves.

     

Defect Engineering and Anisotropic Modulation of Ionic Transport in Perovskite Solid Electrolyte LixLa(1−x)/3NbO3

Solid electrolytes, such as perovskite Li_3xLa_2/1−xTiO₃, Li_xLa_(1−x)/3NbO₃ and garnet Li₇La₃Zr₂O₁₂ ceramic oxides, have attracted extensive attention in lithium-ion battery research due to their good chemical stability and the improvability of their ionic conductivity with great potential in solid electrolyte battery applications. These solid oxides eliminate safety issues and cycling instability, which are common challenges in the current commercial lithium-ion batteries based on organic liquid electrolytes. However, in practical applications, structural disorders such as point defects and grain boundaries play a dominating role in the ionic transport of these solid electrolytes, where defect engineering to tailor or improve the ionic conductive property is still seldom reported. Here, we demonstrate a defect engineering approach to alter the ionic conductive channels in Li_xLa_(1−x)/3NbO₃ (x = 0.1~0.13) electrolytes based on the rearrangements of La sites through a quenching process. The changes in the occupancy and interstitial defects of La ions lead to anisotropic modulation of ionic conductivity with the increase in quenching temperatures. Our trial in this work on the defect engineering of quenched electrolytes will offer opportunities to optimize ionic conductivity and benefit the solid electrolyte battery applications.     

Facile Synthesis of Dibenzopentalene Dianions and Their Application as New π‐Extended Ligands

Reduction of phenyl(silyl)ethynes with potassium followed by quenching with iodine gave dibenzopentalenes in moderate yields. The intermediates of the reactions, dipotassium dibenzopentalenides, were isolated. The first dibenzopentalene–transition‐metal complex was successfully synthesized. The ruthenium atoms are located above the six‐membered rings. However, X‐ray diffraction analysis and theoretical calculations revealed that the aromatic nature of the five‐membered rings was retained. The cyclic voltammetry of the Ru complex revealed two oxidation waves with relatively large separation.     

Strong generators of the subregular $$\mathcal {W}$$W-algebra $$\mathcal {W}^{K-N}(\mathfrak {sl}_N,f_{sub})$$WK-N(slN,fsub) and combinatorial description at critical level

Letters in Mathematical Physics - We construct explicitly strong generators of the affine $$\mathcal {W}$$-algebra $$\mathcal {W}^{K_0-N}(\mathfrak {sl}_N, f_{sub})$$ of subregular type A....