Time-resolved EPR revealed C(sp3)-H activation through a photo-enhanced phthalimide-N-oxyl (PINO) radical.

The time-resolved electron paramagnetic resonance (EPR) technique under operando photochemical conditions as an efficient strategy to investigate the fast formation of abundant long-lived PINO radicals (t1/2 = 204 s) and their activation of the C(sp3)-H process has been researched. This developed method offers a pathway for investigating the properties and tracking the transformations of radical species in the photoredox reaction process.

Directing group strategies in rhodium-catalyzed C-H amination.

Construction of a carbon-nitrogen bond is one of the most prevalent operations in nature and organic synthesis. The resulting amino compounds are privileged structural fragments in natural products, pharmaceutical drugs, and functional materials. With the rapid advancement of C-H bond activation, directing-group strategies in C-H amination catalyzed by rhodium have emerged. This reaction approach considerably enhances the step economy and atom economy of the reaction, and it complies with green chemistry and atom economy. The reactivity and selectivity of chelation-assisted rhodium-catalyzed C-H amination are discussed in relation to the types of aminating reagent, as well as the challenges and future development prospects in this field.

Biomimetic catalytic aerobic oxidation of C-sp(3)-H bonds under mild conditions using galactose oxidase model compound CuIIL.

Developing highly efficient catalytic protocols for C-sp(3)-H bond aerobic oxidation under mild conditions is a long-desired goal of chemists. Inspired by nature, a biomimetic approach for the aerobic oxidation of C-sp(3)-H by galactose oxidase model compound CuIIL and NHPI (N-hydroxyphthalimide) was developed. The CuIIL-NHPI system exhibited excellent performance in the oxidation of C-sp(3)-H bonds to ketones, especially for light alkanes. The biomimetic catalytic protocol had a broad substrate scope. Mechanistic studies revealed that the CuI-radical intermediate species generated from the intramolecular redox process of CuIILH2 was critical for O2 activation. Kinetic experiments showed that the activation of NHPI was the rate-determining step. Furthermore, activation of NHPI in the CuIIL-NHPI system was demonstrated by time-resolved EPR results. The persistent PINO (phthalimide-N-oxyl) radical mechanism for the aerobic oxidation of C-sp(3)-H bond was demonstrated.

TiO2 nanotube arrays sensitized by copper (II) porphyrins with efficient interfacial charge transfer for the photocatalytic degradation of 4-nitrophenol.

In this paper, photocatalysts based on TiO2 nanotubes (TNTs) and TiO2 nanotube arrays (TNTAs) sensitized by Cu(II) meso-tetrakis(N-ethylpyridinium-4-yl) porphyrin (CuTEPyP) were synthesized and their structures were characterized by various analytical methods. The photocatalytic activities of both composites were then investigated through degradation of 4-nitrophenol (4-NP) in aqueous solutions under visible light irradiation. It was found that CuTEPyP/TNTAs could eliminate 95% 4-NP within 4 h, which was considerably higher than the yield obtained with CuTEPyP/TNTs (56%) under the same conditions. Compared to CuTEPyP/TNTs, the improved photocatalytic activity of CuTEPyP/TNTAs can be ascribed to increased light absorption, high separation rate of photo-generated charge pairs, and efficient charge transfer. A plausible photocatalytic degradation mechanism involving hydroxyl radicals, superoxide radical anions and singlet oxygen species was also proposed. This work presents an efficient paradigm for eliminating 4-NP under visible light irradiation.

Biomimetic Aerobic Epoxidation of Alkenes Catalyzed by Cobalt Porphyrin under Ambient Conditions in the Presence of Sunflower Seeds Oil as a Co-Substrate.

In this work, a mild and sustainable catalytic aerobic epoxidation of alkenes catalyzed by cobalt porphyrin was performed in the presence of sunflower seeds oil. Under ambient conditions, the conversion rate of trans-stilbene reached 99%, and selectivity toward epoxide formation was 88%. The kinetic studies showed that the aerobic epoxidation followed the Michaelis-Menten kinetics. Mass spectroscopy and in situ electron spin resonance indicated that linoleic acid was converted to fatty aldehydes via hydroperoxide intermediates. A plausible mechanism of epoxidation of alkenes was accordingly proposed.

pH-Dependence of the Aqueous Phase Room Temperature Brønsted Acid-Catalyzed Chemoselective Oxidation of Sulfides with H2O2.

A pH-dependence of the Brønsted acid-catalyzed oxidation of sulfides to the corresponding sulfoxides with H2O2 is reported for the first time based on our systematic investigation of the catalytic performance of a series of Brønsted acids. For all of the Brønsted acids investigated, the catalytic performances do not depend on the catalyst loading (mol ratio of Brønsted acid to substrate), but rather depend on the pH value of the aqueous reaction solution. All of them can give more than 98% conversion and selectivity in their aqueous solution at pH 1.30, no matter how much the catalyst loading is and what the Brønsted acid is. This pH-dependence principle is a very novel perspective to understand the Brønsted-acid catalysis system compared with our common understanding of the subject.

Value of serum marker HE4 in pulmonary carcinoma diagnosis.

An effective blood test is valuable to aid clinicians in making case management decisions. The present study was to analyze the value of four serum tumor markers for the diagnosis of pulmonary carcinoma. The case group consisted of 80 pulmonary carcinoma patients, which were compared to a control group of 30 patients with benign pulmonary disease and a control group of 30 healthy individuals. Serum levels of carcinoma embryonic antigen (CEA), cytokeratin protein fragment 21-1 (CYFRA21-1), neuron-specific enolase (NSE), and human epididymis protein 4 (HE4) were detected using electrochemiluminescence. Serum CEA, NSE, CYFRA21-1, and HE4 levels were significantly higher in pulmonary carcinoma patients than those in both control groups (P < 0.05). Serum CEA and HE4 levels were significantly higher in adenocarcinoma patients, while serum CYFRA21-1 levels were significantly higher in squamous cell carcinoma patients and serum NSE levels were significantly higher in small cell lung cancer (SCLC) patients (P < 0.05). Analysis of area-under-the-receiver operating characteristic (ROC) curves (AUC) revealed that serum CYFRA21-1, CEA, and HE4 levels were valuable for squamous cell carcinoma, serum CEA and HE4 levels were valuable for adenocarcinoma, and serum NSE level was valuable for SCLC (P < 0.05). Serum CEA and HE4 levels of pulmonary carcinoma patients with metastasis were higher than those with TNM stage I-II or III-IV disease without metastasis. In brief, detection of serum HE4 levels may be useful in auxiliary diagnosis and evaluation of the progression of pulmonary carcinoma.

Amino alcohol-modified ß-cyclodextrin inducing biomimetic asymmetric oxidation of thioanisole in water.

Inspired by ß-CD, a macrocyclic oligomers of D-(+)-glucopyranose and a renewable material, which could be obtained from starch, that can promote a lot of organic reactions in water, a green solvent, several amino alcohol-modified ß-CDs CD-1 to CD-7 were synthesized in the yields of 36-61%. Their conformations in vacuum and in aqueous solution were optimized by quantum calculation. Their complexes with sodium molybdate prepared in situ were characterized by (1)H NMR and were applied in the asymmetric oxidation of thioanisole. Their performance in inducing enantioselectivity was investigated in detail. For the optimal one, CD-1, moderate enantioselectivity (56% ee) was achieved in aqueous CH(3)COONa-HCl buffer solution (pH 7.0). The abilities of CD-1 to CD-7 to induce asymmetry are highly dependent on the pH value of the reaction medium and the structure of the modifying group. The origin of the moderate enantioselectivity and the reaction mechanism were investigated with the aid of (1)H ROESY NMR studies and quantum calculation. The moderate enantioselectivity was attributed to the two different binding models between CD-1 and thioanisole, which could be defined as intramolecular catalysis and intermolecular catalysis, in which intramolecular catalysis gave (S)-methyl phenyl sulfoxide and intermolecular catalysis gave (R,S)-methyl phenyl sulfoxide.

Photocatalytic degradation of methyl orange over metalloporphyrins supported on TiO2 Degussa P25.

The photocatalytic activity of meso-tetraphenylporphyrins with different metal centers (Fe, Co, Mn and Cu) adsorbed on TiO(2) (Degussa P25) surface has been investigated by carrying out the photodegradation of methyl orange (MO) under visible and ultraviolet light irradiation. The photocatalysts were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), diffuse reflectance UV (DRS-UV-vis) and infrared spectra. Copper porphyrin-sensitized TiO(2) photocatalyst (CuP-TiO(2)) showed excellent activity for the photodegradation of MO whether under visible or ultraviolet light irradiation. Natural Bond Orbital (NBO) charges analysis showed that methyl orange ion is adsorbed easier by CuP-TiO(2) catalyst due to the increase of induced interactions.

Highly efficient controllable oxidation of alcohols to aldehydes and acids with sodium periodate catalyzed by water-soluble metalloporphyrins as biomimetic catalyst.

Highly efficient controllable oxidation of alcohols to aldehydes or acids by sodium periodate in the presence of water-soluble manganese porphyrins (meso-tetrakis(N-ethylpyridinium-4-yl)manganese porphyrin, MnTEPyP) with different reaction media has been reported. The manganese porphyrin showed excellent activity for the controllable oxidation of various alcohols under mild conditions. Moreover, different factors influencing alcohol oxidation, for example, oxidant, catalyst amount, temperature, and solvent, have been investigated. A plausible mechanism for the controllable oxidation of alcohol has been proposed.

[Determination of life elements in hair and urine with brick-tea fluorosis in Inner Mongolia by ICP-OES].

In brick-tea fluorosis affected areas XiLinHot city in Inner Mongolia, herdsmen who like drinking a large amount of brick tea in everyday life and Han habitants rarely drinking brick tea as control group were enrolled, and their hair and urine were sampled. The concentrations of Ca, Mg, K, Al, P, Cu, Zn and Fe in hair and urine were detected using ICP-OES. The RSDs of the method were between 2.32% and 8.03%, and the analytical results of the hair reference samples were consistent with the certified values. The results showed that the contents of Al, Mg and K in hair, and contents of Al and Ca in urine of herdsmen who were accustomed to drinking brick tea were obviously higher than those in control group (P<0.05), while the contents of K in urine of herdsmen who were accustomed to drinking brick tea was lower than those in control group (P<0.05), and other elements did not have statistic significance (P>0.05). Chronically drinking brick tea probably brings metabolic disorder of Ca and Al in human body, and the interaction mechanism of life elements in brick-tea fluorosis should be further studied.

[In-situ DRIFTS study of coupling partial oxidation of methane and carbon dioxide reforming].

8%Ru-5%Ce/gamma-Al2O3 catalyst exhibited excellent catalytic performance for low temperature activation of methane. Although the conversion rates of methane were 25.3% for exothermal partial oxidation of methane, and 0.8% for endothermal carbon dioxide reforming, whose activity was rather low, 38.8% of conversion rate of methane could be obtained for the obtained coupling reaction at 500 degrees C owing to the coupling intensification between endothermal carbon dioxide reforming reaction and exothermal partial oxidation of methane. The mechanism of coupling partial oxidation of methane and carbon dioxide reforming on supported Ru catalyst was investigated by in-situ DRIFTS. The adsorption of CO on 8%Ru-5%Ce/gamma-Al2O3 showed that two kinds of doublet peaks which were characteristic adsorption of the gaseous CO at 2167 cm(-1) (2118 cm(-1)) to form Ru(CO)2 at 2031 cm(-1) (2034 cm(-1)) to form Ce(CO)2 were observed. These CO adsorption species wee easy to be desorbed from the surface of the catalyst at high temperature. The results of in-situ DRIFTS showed that carbonate, formal (formate) and carbon monoxide formed on the surface of catalyst, and formal (formate) was intermediate for the methane partial oxidation. This intermediate was formed through the combination of the adsorption species of methane CHx and the lattice oxygen adsorption species on the surface of catalyst, and syngas was produced through the splitting of this intermediate. The DRIFTS researching on carbon dioxide reforming showed that there was no new adsorption species on the surface of the catalyst, which indicated that the mechanism for carbon dioxide reforming was through the dissociation of the adsorbed methane and carbon dioxide. During the reaction of the coupling of carbon dioxide reforming reaction and partial oxidation of methane, there was hydroxyl adsorption species on the surface of catalyst. The mechanism of coupling methane, carbon dioxide and oxygen might be composed of the above two reaction mechanism and the bridging hydroxyl group adsorption species Ru-(OH)2 might contribute to the coupling reaction.

Highly efficient selective oxidation of alcohols to carbonyl compounds catalyzed by ruthenium (III) meso-tetraphenylporphyrin chloride in the presence of molecular oxygen.

Efficient selective oxidation of alcohols to carbonyl compounds by molecular oxygen with isobutyraldehyde as oxygen acceptor in the presence of metalloporphyrins has been reported. Ruthenium (III) meso-tetraphenylporphyrin chloride (Ru(TPP)Cl) showed excellent activity and selectivity for oxidation of various alcohols under mild conditions. Moreover, different factors influencing alcohols oxidation, for example, catalyst, solvent, temperature, and oxidant, have been investigated. In large-scale oxidation of benzyl alcohol, the isolated yield of benzaldehyde of 89% was observed.

Selective oxidation of sulfides to sulfoxides catalyzed by ruthenium (III) meso-tetraphenylporphyrin chloride in the presence of molecular oxygen.

Highly efficient selective oxidation of sulfides to sulfoxides by molecular oxygen catalyzed by ruthenium (III) meso-tetraphenylporphyrin chloride (Ru(TPP)Cl) with isobutyraldehyde as oxygen acceptor has been reported. In large-scale experiment of thioanisole oxidation, the isolated yield of sulfoxide of 92% was obtained and the turnover number reached up to 92,000.

Isolation and Characterzation of p160.2, a Signal Transducing Protein Downstream of Jak3.

Nonreceptor tyrosine kinase Jak3, which binds to intracellular domain of interleukin-2 receptor gamma subunit (IL-2Rgamma), plays an important role in IL-2 function. To find downstream signal transducer of Jak3, the N-terminal region JH3-JH7 of Jak3 was used as a baitg to screen a cDNA library by using the yeast two-hybrid system. One real true clone was obtained out of 10(5) cotransformants. Sequencing indicated that it encoded a p160.2 protein fragment which consisted of 399 amino acid residues. Further results showed that the p160.2 fragment merely bound to the intact JH3-JH7 through its C-terminal. Northern blot revealed that human p160.2 shared homology with monkey p160.2, but was different from mouse p160.2; and p160.2 was widely expressed in various tissues.