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991.
Zeolite synthesis in contemporary chemical industries is predominantly conducted using organic structure-directing agents (OSDAs), which are chronically hazardous to humans and the environment. It is a growing trend to develop an eco-friendly and nuisanceless OSDA for zeolite synthesis. Herein, choline is employed as a non-toxic and green OSDA to synthesize high silica Y zeolite with SiO2/Al2O3 ratios of 6.5–6.8. The prepared Y zeolite samples exhibited outstanding (hydro)thermal stability at ultrahigh temperature owing to the higher SiO2/Al2O3 ratio. The XRF, SEM, 29Si-NMR and 13Na+ results suggested that choline plays a structure-directing role in the synthesis of Y zeolite, while the feed molar fraction of Na+ is a crucial determinant for the framework SiO2/Al2O3 ratio and the crystal morphology. 相似文献
992.
Pt/Eu2O3-CeO2 materials with different Eu concentrations were prepared and applied to toluene destruction, and the remarkable promotion impact of EuOx on Pt/CeO2 can be observed. The characterization results reveal that the presence of EuOx significantly enhances the redox property, lattice O concentration, and Ce3+ ratio of the Pt/CeO2 material, which facilitates the dispersion and activity of Pt active sites and thus accelerates the decomposition process of toluene. Among all catalysts, a sample with an Eu content of 2.5 at.% (Pt/EC-2.5) possesses the best catalytic activity with 0.09 vol% of toluene completely destructed at 200 °C under a relatively high GHSV of 50000 h?1. The possible reaction pathway and mechanism of toluene combustion over Pt/Eu2O3-CeO2 samples are presented according to in-situ DRIFTS, which confirms that the toluene oxidation process obeys the Mars-van Krevelen mechanism with aldehydes and ketones as primary organic intermediates. 相似文献
993.
Ying Fu Yin‐Xia He Hong‐Xia Hou Wen‐Bo Zhu Hu‐Lin Li Chao Wu Fang‐Yan Xian 《Acta Crystallographica. Section C, Structural Chemistry》2013,69(3):282-284
2,2′‐Anhydro‐1‐(3′,5′‐di‐O‐acetyl‐β‐D‐arabinofuranosyl)uracil, C13H14N2O7, was obtained by refluxing 2′,3′‐O‐(methoxymethylene)uridine in acetic anhydride. The structure exhibits a nearly perfect C4′‐endo (4E) conformation. The best four‐atom plane of the five‐membered furanose ring is O—C—C—C, involving the C atoms of the fused five‐membered oxazolidine ring, and the torsion angle is only −0.4 (2)°. The oxazolidine ring is essentially coplanar with the six‐membered uracil ring [r.m.s. deviation = 0.012 (5) Å and dihedral angle = −3.2 (3)°]. The conformation at the exocyclic C—C bond is gauche–trans which is stabilized by various C—H...π and C—O...π interactions. 相似文献
994.
Zhi‐He Deng Zhen‐Jian Peng Jun Huang 《Acta Crystallographica. Section C, Structural Chemistry》2013,69(5):467-470
The title compound, poly[[μ4‐5‐carboxy‐4‐carboxylato‐2‐(pyridin‐4‐yl)‐1H‐imidazol‐1‐ido]disilver(I)], [Ag2(C10H5N3O4)]n, was synthesized by reacting silver nitrate with 2‐(pyridin‐4‐yl)‐1H‐imidazole‐4,5‐dicarboxylic acid (H3PyIDC) under hydrothermal conditions. The asymmetric unit contains two crystallographically independent AgI cations and one unique HPyIDC2− anion. Both AgI cations are three‐coordinated in distorted T‐shaped coordination geometries. One AgI cation is coordinated by one N and two O atoms from two HPyIDC2− anions, while the other is bonded to one O and two N atoms from two HPyIDC2− anions. It is interesting to note that the HPyIDC2− group acts as a μ4‐bridging ligand to link the AgI cations into a three‐dimensional framework, which can be simplified as a diamondoid topology. The thermal stability and photoluminescent properties of the title compound have also been studied. 相似文献
995.
XiaoDan Fu XingQun Guo XingWei Li LiDong He YuShe Yang YouXi Chen 《Tetrahedron: Asymmetry》2013,24(13-14):827-832
An asymmetric synthesis of the melatonin receptor agonist Ramelteon 1 has been achieved, which involved a tandem C–H activation–alkylation/Heck reaction and subsequent highly diastereoselective asymmetric Michael addition to generate the corresponding chiral intermediate, which was readily converted into Ramelteon 1 in 19% overall yield in 15 linear steps. 相似文献
996.
Andrew S. Rowan Thomas S. Moody Roger M. Howard Toby J. Underwood Iain R. Miskelly Yanan He Bo Wang 《Tetrahedron: Asymmetry》2013,24(21-22):1369-1381
Libraries of highly enantioenriched secondary alcohols in both enantiomeric forms were synthesised by enzymatic reduction of their parent ketones using selectAZyme? carbonyl reductase (CRED) technology. Commercially available CREDs were able to reduce a range of substrate classes efficiently and with very high enantioselectivity. Matching substrate classes to small subsets of CREDs enabled the fast development of preparative bioreductions and the rapid generation of 100–1500 mg samples of chiral alcohols in typically >95% ee and the majority in ?99.0% ee. The conditions for small scale synthesis were then scaled up to 0.5 kg to deliver one of the chiral alcohols, (S)-1-(4-bromophenyl)-2-chloroethanol, in 99.8% ee and 91% isolated yield. 相似文献
997.
Fan Yang Hongmei Yang Baozhu Tian Jinlong Zhang Dannong He 《Research on Chemical Intermediates》2013,39(4):1685-1699
Mo and C co-doped TiO2 photocatalysts were successfully prepared by a calcination–hydrothermal method. The catalysts were characterized by XRD, XPS, DRS, FTIR, and Raman spectroscopy. Results from photocatalysis showed that 1%Mo–C4/TiO2 had excellent visible light photocatalytic activity. This may be ascribed not only to the Mo and C doping but also to synergism between the Mo and C. 相似文献
998.
You-An Xiao Zhi-Qiang Wang Xue-Min Wang Yi Hui Yong Ling Xin-Yang Wang Li-Qin He 《中国化学快报》2013,24(8):727-730
Novel 2-aminoimidazolone derivatives were synthesized.Most compounds displayed strong anticancer activities against human carcinoma cells in vitro.Compounds 8a,8b and 8j exhibited optimal activity superior to 5-FU in most cancer cells tested.Especially,the lC50s of 8b(12.6-21.5μmol/L) against five tumor cells were 1 -4 fold less than those of 5-FU(18.4-56.1μmol/L) in vitro.Furthermore,comp以ound 8b could induce SMMC-7721 cell apoptosis in a dose-dependent manner.Therefore,our novel findings may provide a new framework for the design of new 2-aminoimidazolone derivatives for the treatment of cancer. 相似文献
999.
Zhihui Luo Wentao Li Donglian Lu Kun Chen Qigai He Heyou Han Mingqiang Zou 《Mikrochimica acta》2013,180(15-16):1501-1507
We report on a facile immunoassay for porcine circovirus type 2 (PCV2) based on surface enhanced Raman scattering (SERS) using multi-branched gold nanoparticles (mb-AuNPs) as substrates. The mb-AuNPs in the immunosensor act as Raman reporters and were prepared via Tris base-induced reduction and subsequent reaction with p-mercaptobenzoic acid (pMBA). They possess good stability and high SERS activity. Subsequently, the modified mb-AuNPs were covalently conjugated to the monoclonal antibody (McAb) against the PCV2 cap protein to form SERS immuno nanoprobes. These were captured in a microtiterplate via a immunoreaction in the presence of target antigens. The effects of antibody concentration, reaction time and temperature on the sensitivity of the immunoassay were investigated. Under optimized assay conditions, the Raman signal intensity at 1,076 cm?1 increases logarithmically with the concentrations of PCV2 in the concentration ranging from 8?×?102 to 8?×?106 copies per mL. The limit of detection is 8?×?102 copies per mL. Compared to conventional detecting methods such as those based on PCR, the method presented here is rapid, facile and very sensitive. Figure
A simple and novel approach to detect porcine circovirus type 2 using surface enhanced Raman scattering (SERS) of multi-branched gold nanoparticles is demonstrated, it has a higher sensitivity than polymerase chain reaction and ELISA. 相似文献
1000.
Suhang He Chan Zhou Haibo Zhang Xiaohai Zhou 《Journal of inclusion phenomena and macrocyclic chemistry》2013,76(3-4):333-344
Binding behaviors of cucurbit[6]uril (CB[6]) and cucurbit[7]uril (CB[7]) with a series of bis-pyridinium compounds N, N’-hexamethylenebis(1-alkyl-4-carbamoyl pyridinium bromide) (HBPB-n) (alkyl chain length, n = 6, 8 and 10) guests were investigated using 1H-NMR, ESI–MS and single crystal X-ray diffraction methods. The results show that CB[6] and CB[7] can form [2]pseudorotaxanes with HBPB-n easily. When increasing the length of tail alkyl chain, the binding site of CB[6] at guest molecules changed from the tail to the middle part, while CB[7] remained located over the tail chain. As CB[6] and CB[7] were added in HBPB-8 aqueous solution, a [3]pseudorotaxane was formed by the inclusion of the internal middle site in CB[6] and the tail chain in CB[7]. 相似文献