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A series of air-stable [(Np3P)Pd(Ar)Br]2 (Np = neopentyl) and (Np3P)Pd(Ar)(amine)Br complexes (amine = morpholine and isobutylamine) have been prepared and tested as precatalysts for the coupling o...

Enolizable ketones have been identified as effective activators for palladium(II) precatalysts in the coupling of aryl bromides and aniline. N-arylation reactions catalyzed by [(DTBNpP)PdCl2]2 (DTB...

A series of [(PNp3)Pd(Ar)Br]2 complexes (PNp3 = trineopentylphosphine, Ar = 4-tolyl, 4-tert-butylphenyl, 2-tolyl, 4-methoxy-2-methylphenyl, 2-isopropylphenyl, and 2,6-dimethylphenyl) were synthesized and structurally characterized by X-ray crystallography and density functional theory optimized structures. The trineopentylphosphine ligand is able to accommodate coordination of other sterically demanding ligands through changes in its conformation. These conformational changes can be seen in changes in percent buried volume of the PNp3 ligand. The binding equilibria of the [(PNp3)Pd(Ar)Br]2 complexes with pyridine derivatives were determined experimentally and analyzed computationally. The binding equilibria are sensitive to the steric demand of the pyridine ligand and less sensitive to the steric demand of the aryl ligand on palladium. In contrast to previous studies, the binding equilibria do not correlate with pyridine basicity. The binding equilibria results are relevant to fundamental ligand coordination steps in cross-coupling reactions, such as Buchwald-Hartwig aminations.

Recently, titanium nitrides have attracted extensive interests as an active material for electrodes in fuel cell because of their excellent physical properties (such as high melting points of approximately 3000 °C), hardness, wear resistance, high electrical conductivity, and chemical stability. This review highlights the background and recent progress in the applications of titanium nitrides in fuel cells. Some typical applications, such as sensors, electrodeposition, methanol oxidation reaction, ethanol oxidation reaction, formic acid oxidation reaction, and oxygen reduction reaction, are clearly classified and discussed in detail.

The mechanism of the bis(trineopentylphosphine)palladium(0) (Pd(PNp3)2)-catalyzed coupling of aryl halides and aniline derivatives was studied in an effort to understand the role of substrate steric effects on the reaction. Prior studies had shown that the rate of Pd/PNp3-catalyzed coupling of aryl bromides and aniline derivatives was largely unaffected by substrate steric demand. The oxidative addition of aryl bromides to Pd(PNp3)2 is found to follow first-order kinetics with a rate that is independent of both ligand and aryl halide concentration. Thus, the rate limiting step for oxidative addition of aryl bromides is irreversible ligand dissociation. In the case of aryl chlorides, the oxidative addition rate has a first-order dependence on [ArCl] and an inverse dependence on [PNp3], indicating a mechanism involving reversible dissociation of the ligand followed by rate limiting oxidative addition. This difference in aryl halide effect was also found for the catalytic coupling reaction. Aryl bromide ster...

A series of [(PNp

Primary leiomyomas of the thyroid are very rare. We here report a case of a 53-year-old woman with a painless mass at the right thyroid, revealed by physical examination. The patient underwent a lobectomy. Frozen sections showed a spindle cell tumor of the thyroid gland. The nuclei of some of the tumor cells were obviously enlarged and deeply stained. Pseudocapsule invasion was observed in small foci. Samples showed neither mitosis nor necrosis and the nature of the tumor was difficult to determine. Paraffin sections showed a well-circumscribed nodular composed of intersecting fascicles of spindled to slightly epithelioid cells with eosinophilic cytoplasm and blunt-ended, cigar-shaped nuclei. We observed no significant nuclear atypia, mitotsis, or necrosis. Immunohistochemical staining showed the tumor cells to be positive for α-smooth muscle actin and h-caldesmon but negative for TG, TTF1, PAX8, S-100, CT, CK, and CD34. The ki-67 index was very low (

A synthesis is reported for 9,10-dimethyl-2,3,6,7-anthracenetetra(thioacetate), an anthracenetetrathiol derivative that may find use in molecular electronics and conducting metal-organic frameworks (MOFs). The easily accessible 2,3,6,7-tetrahydroxy-9,10-dimethylanthracene was treated with 2-(4-pyridyl)ethanethiol in molten p-toluenesulfonic acid to yield the tetra(thioether), which was methylated and then deprotected with triethylamine in the presence of acetic anhydride to yield 9,10-dimethyl-2,3,6,7-anthracenetetra(thioacetate), a protected form of the tetrathiol. Separately, the first synthesis of benzenepentathiol and streamlined syntheses of 1,2,4,5-benzenetetra(thioacetate) and benzenehexathiol are reported.

Near-infrared (NIR) lasers are key components for applications, such as telecommunication, spectroscopy, display, and biomedical tissue imaging. Inorganic III-V semiconductor (GaAs) NIR lasers have achieved great successes but require expensive and sophisticated device fabrication techniques. Organic semiconductors exhibit chemically tunable optoelectronic properties together with self-assembling features that are well suitable for low-temperature solution processing. Major blocks in realizing NIR organic lasing include low stimulated emission of narrow-bandgap molecules due to fast nonradiative decay and exciton-exciton annihilation, which is considered as a main loss channel of population inversion for organic lasers under high carrier densities. Here we designed and synthesized the small organic molecule (E)-3-(4-(di-p-tolylamino)phenyl)-1-(1-hydroxynaphthalen-2-yl)prop-2-en-1-one (DPHP) with amphiphilic nature, which elaborately self-assembles into micrometer-sized hemispheres that simultaneously serves as the NIR emission medium with a photoluminescence quantum efficiency of ∼15.2%, and the high-Q (∼1.4 × 10(3)) whispering gallery mode microcavity. Moreover, the radiative rate of DPHP hemispheres is enhanced up to ∼1.98 × 10(9) s(-1) on account of the exciton-vibrational coupling in the solid state with the J-type molecular-coupling component, and meanwhile the exciton-exciton annihilation process is eliminated. As a result, NIR lasing with a low threshold of ∼610 nJ/cm(2) is achieved in the single DPHP hemisphere at room temperature. Our demonstration is a major step toward incorporating the organic coherent light sources into the compact optoelectronic devices at NIR wavelengths.

The super paramagnetic nanoparticles Fe3O4/(2-hydroxyethty methacrylate-co-dimethyl dially ammonium chloride) copolymer, i.e. Fe3O4/P(HEMA–DMDAAC), with positive charge and active epoxy groups simultaneously, were synthesized by a surface-initiated radical polymerization and activation reaction with epoxy chloropropane. The production particles were characterized by Fourier transform infrared spectroscopy (FT-IR), thermogravimetric analysis (TG), transmission electron microscopy (TEM), and vibrating sample magnetometry (VSM). It was verified that the magnetic microspheres held small diameters of 80–100 nm and displayed super paramagnetic property with saturation magnetization of 38.9 emu/g. The candida rugosa lipase (CRL), meanwhile, was immobilized onto the magnetic microspheres via electrostatic adsorption and covalent binding, the loading amount of lipase was 68.3 ± 0.5 mg CRL/g support and the activity recovery of the obtained immobilized lipase reached to 60.4% (±1.6%).

A novel spherical composite of polyvinyl alcohol (PVA) and attapulgite (ATP) with macroreticular structure, i.e. MR-PVA/ATP composites, was prepared as an adsorbent for some contaminations from aqueous environment, which would hold the advantages of PVA and ATP in the same time. The resulting adsorbents hold uniform and rich aperture with good mass transfer property, processing properties and stability. It has been proved with easy separation and excellent adsorption for methylene blue and lead in aqueous solution, and the adsorption rate will be accelerated when increasing porogen in its preparation. The adsorption process of methylene blue and lead on it includes both chemo-adsorption and physical adsorption. The adsorption process all fits the pseudo second order kinetics very well with rapid initial adsorption rate. The addition of attapulgite increased the adsorption capacity of lead ions significantly. By further graft functional groups on the ATP, it has potential to prepare various adsorbents to satisfy specific requirements. Such kind of adsorption material will perform a wide application prospect in the purification treatment for wastewater.

The nanocomposites based on organic-inorganic hybrid have been attracting much attention due to their potential applications used as new type of functional materials, such as colloidal stabilizers, electro-optical devices, and nanocomposites materials. The organic-inorganic hybrid of poly(acrylic acid-acrylonitrile)/attapulgite, P(A-N)/AT nanocomposites, were prepared by using in situ polymerization and composition of acrylic acid (AA) and acrylonitrile (AN) onto modified attapulgite (AT) nanoparticles. The resulting P(A-N)/AT nanocomposites were transformed into novel nano-adsorbent of poly(acrylic acid-acryloamidoxime)/attapulgite by further functionalization, i.e. P(A-O)/AT nano-adsorbent. The adsorption properties of P(A-O)/AT toward metal ions were determined, and the results indicated that the adsorbents with nanocomposite structure held a good of selectivity to Pb(2+) among numerous metal ions. The maximum removal capacity of Pb(2+) was up to 109.9 mg/g and it is notable to see that the adsorption removal of P(A-O)/AT nano-adsorbent for Pb(2+) could achieve more than 96.6% when the initial concentration of Pb(2+) was 120.0 mg/l. The kinetics, isotherm models, and conductivity were introduced to study the adsorption mechanism of P(A-O)/AT for Pb(2+) and it was concluded that it could be chemisorptions process and the best coordination form took place when AO:AA:Pb(2+) = 1:1:1. In addition, after simply treated with CTAB, P(A-O)/AT nano-adsorbent showed better adsorption properties for phenol than the same kinds of materials.