摘要:

AbstractA mild and efficient route for the synthesis of quinolines and polycyclic quinolines utilizing Gadolinium triflate (Gd(OTf)3) as a novel catalystviaFriedländer annulation in ionic liquid 1‐n‐butyl‐3‐methyl‐imidazolium hexafluorophosphate [Bmim][PF6] under mild conditions was

ISSN:0009-4536    

DOI:10.1002/jccs.200900128

出版商:WILEY‐VCH Verlag    

年代:2009

数据来源: WILEY

摘要:

AbstractWe have demonstrated that 4,4′‐dimethyl 2,2′‐bipyridine as ligand for Pd(II) catalysts was very efficient for oxidative Heck‐type coupling reaction of arylboronic acids with olefins in DMA or CH3CN under atm air at 80 °C. The presence of chelated bipyridine ligand isindispensable to achieve high reaction yields and to suppress the formation of biphenyl as homocoupled

ISSN:0009-4536    

DOI:10.1002/jccs.200900129

出版商:WILEY‐VCH Verlag    

年代:2009

数据来源: WILEY

摘要:

AbstractCurcusinol (1), a new resveratrol trimer, was isolated and identified from the rhizomes ofCurculigo sinensis(Hypoxidaceae), together with five known phenolic compounds: curcapital (2), pilosidine (3), crassifoside A (4), curculigoside I (5) and phegopolin (6). The new compound1was determined as an oligostilbenoid on the basis of various spectroscopic methods, especially intensive 2D‐NMR (COSY, HMQC, HMBC and NOESY) technique

ISSN:0009-4536    

DOI:10.1002/jccs.200900130

出版商:WILEY‐VCH Verlag    

年代:2009

数据来源: WILEY

摘要:

AbstractNi nanoparticles (Ni(1) and Ni(2)) and Ni loaded SiMCM‐41 (15Ni/SiMCM‐41) were prepared and characterized with XRD, TEM, N2adsorption, CO chemisorption, and H2‐TPR. The Ni specific surface area followed the order of 15Ni/SiMCM‐41>Ni(1)>>Ni(2), whereas the Ni particle size exhibited the opposite trend. These catalysts were utilized for vapour phase hydrogenation of cinnamaldehyde at 1 atm and 200 °C in a fixed‐bed, down flow reactor. The main products include hydrocinnamaldehyde, styrene, ethylbenzene, and 2‐phenyl‐1‐propanol. The catalytic activity decreased in the same order as that of Ni specific surface areas. The SiMCM‐41 support possessed very large surface area, leading to enhanced dispersion and specific surface area of Ni nanoparticles. As a result, the 15Ni/SiMCM‐41 catalyst exhibited the highest activity. Based on the investigation of reaction pathways, it is important to emphasize that both hydrogenation and hydroelimination of formaldehyde (hydrodeformylation) occur in the v

ISSN:0009-4536    

DOI:10.1002/jccs.200900131

出版商:WILEY‐VCH Verlag    

年代:2009

数据来源: WILEY

摘要:

AbstractThe composite of manganese dioxide‐polyaniline (MnO2‐PANI) was successfully prepared by cyclic voltammetry (CV) from a 0.5 M H2SO4solution containing 0.2 M aniline and 0.5 M MnSO4. Scanning electron microscopy (SEM) images revealed that cauliflower like manganese dioxides entangled with PANI were generated. The spectra obtained from UV‐vis spectrophotometry (UV‐vis) and Fourier transform infrared spectrometry (FTIR) strongly demonstrated that this novel composite was composed by MnO2and PANI, and also there was an interaction between MnO2and PANI. Then, for the first time, this resultant composite was modified on a graphite electrode and employed in the oxygen reduction reaction (ORR), subsequently, the obtained cyclic voltammograms (CVs) verified that ORR could proceed on this resultant composite of MnO2‐PANI. Lastly, the possible catalysis mechanism of MnO2‐PANI towards ORR was proposed based on the results we acquired. Developing a novel substrate on which ORR could proceed is the main contribution o

ISSN:0009-4536    

DOI:10.1002/jccs.200900132

出版商:WILEY‐VCH Verlag    

年代:2009

数据来源: WILEY

摘要:

AbstractAluminium‐27 nuclear magnetic resonance spectroscopy (27Al NMR) does not yield fully resolved spectra for end‐group aluminates attached to different silicate species. For example, the chemical shifts of all q1(end‐group aluminates) lying in the range δ ≈ 72.2–77 ppm are observed on average at δ ≈ 74.6 ppm in an NMR spectrum. With the aim of better characterisation of different q1linked units, we first made some attempts to resolve the signals that might arise from different q1linkages through the application of suitable experimental methods and then followed up this work by applying some calculation methods. Some of the observed differences and evidence have not been previously detected experimentally, but were clearly apparent from our calculations (Table 1) as well as in our experimental data. Therefore, in such a situation, theoretical calculations of NMR chemical shifts can be very helpful and can provide some missin

ISSN:0009-4536    

DOI:10.1002/jccs.200900133

出版商:WILEY‐VCH Verlag    

年代:2009

数据来源: WILEY

摘要:

AbstractNi‐loaded pure siliceous and aluminosilicate MCM‐41 (Ni/MCM‐41) and nickel‐loaded silica (15Ni/SiO2) were synthesized via wet impregnation and were characterized by various techniques. The H2consumption in the TPR analysis was found to be proportional to the Ni amount in the calcined samples. After reduction the average Ni particle sizes of 15Ni/MCM‐41 and 15Ni/SiO2were 9–12 and 16 nm, respectively, by means of XRD and TEM measurements. All catalysts owned weak and intermediate Lewis acid sites that increased slightly with increasing the Ni amount and the Al content. In the liquid phase hydrogenation of t,t,c‐1,5,9‐cyclododecatriene over Ni/MCM‐41, the catalytic activity was parallel to the Ni content and enhanced slightly with the acid amount of the catalysts. Consequently, it was proposed that the Ni metallic sites contributed the major effect to the catalytic activity while the Lewis acid sites promoted a small but significant influence on the catalytic performance. It is noteworthy that all 15Ni/MCM‐41 catalysts exhibited remarkably higher activity than that of the conventiona

ISSN:0009-4536    

DOI:10.1002/jccs.200900134

出版商:WILEY‐VCH Verlag    

年代:2009

数据来源: WILEY

摘要:

AbstractThe self‐assembly of Co(II) with two diaminodiamide ligands, 4,7‐diazadecanediamide and 4,8‐diazaundecanediamide, gave two different crystals, [(C8H18N4O2)Co(OH)2Co(C8H18N4O2)]Cl2(1) [Co(C9H20N4O2)(Cl)(H2O)]·Cl·2H2O (2). Structures of1and2were characterized by single‐crystal X‐ray diffraction analysis. Structural data for1shows a novel type of binuclear complex with distorted octahederal coordination geometry around the Co atoms through the hydroxo bridges. By using inter‐connector N‐H···N hydrogen bonding interactions as building forces, each cationic moiety [(C8H18N4O2)Co(OH)2Co(C8H18N4O2)]2+is linked to neighboring ones, producing a charged hydrogen‐bonded 1D chain‐like structure. The chains are further connected into a 2D layer in a (4,4)‐topology via N‐H···Clfreehydrogen‐bonding interactions. Structural data for2indicate that the cobalt atom adopts a six‐coordinated N2O4environment, giving a distorted octahedral geometry, where two N‐ and two O‐donor sets of ligand located at equatorial positions and one water and one chloride occupied at axial positions. Through NH···Cl‐Co and OH···Cl‐Co contacts, each cationic moiety [Co(C9H20N4O2)(Cl)(H2O)]+in2is linked to neighboring ones, producing a charged hydrogen‐bonded 1D chainlike structure. Thus, the crystal‐engineering approach has proved successful in the solid‐state packing due

ISSN:0009-4536    

DOI:10.1002/jccs.200900135

出版商:WILEY‐VCH Verlag    

年代:2009

数据来源: WILEY

摘要:

AbstractWe prepared the PLGA‐loaded anti‐cancer drug and coated it with quantum dots to make it a dual‐function nanoparticles, and analyzed its potential use in cellular imaging and curing cancers. Two cancer cell lines, paclitaxel‐sensitive KB and paclitaxel‐resistant KB paclitaxel‐50 cervical carcinoma cells, were the relativistic models for analysis of the cytotoxicity of free paclitaxel and paclitaxel‐loaded PLGA conjugated with quantum‐dot nanoparticles. The paclitaxel‐loaded PLGA conjugated with quantum dots nanoparticles were significantly more cytotoxic than the free paclitaxel drug in paclitaxel‐resistant KB paclitaxel‐50 cells. This might have been because the cancer cells developed multi‐drug resistance (MDR), which hampered the action of free paclitaxel by pumping its molecules to extracellular areas. Addition of verapamil, a P‐glycoprotein inhibitor, reversed the MDR mechanism and significantly reduced KB paclitaxel‐50 cell viability. As a result, KB paclitaxel‐50 was highly associated with MDR on the cell membrane. The cytotoxicity results indicated that PLGA nanoparticles served as drug carriers and protected the drugs from MDR‐accelerated efflux. Combined quantum dots with PLGA nanoparticles allowed additional fun

ISSN:0009-4536    

DOI:10.1002/jccs.200900136

出版商:WILEY‐VCH Verlag    

年代:2009

数据来源: WILEY

摘要:

AbstractWe report the sonophysically‐exfoliated methods access to the preparation of homogeneous‐free multi‐walled carbon nanotubes (MWCNTs) in water solution. Highly stable, uniform, individual MWCNTs are entirely performed through sodium dodecylsulfate surfactants by means of a tip sinicator. HRTEM images show that the crystalline finger walls of individual CNTs are apparently observed. Raman spectrum of MWCNTs shows that the so‐calledG'‐band, associated with metallic electronic structure, was significantly observed at 2644 cm−1with full‐width at half‐maximum of 262 cm−1, indicating that the sonication physical methods do not alter their electric properties. Owing to its easy‐to‐use procedure and low cost of implementation, this approach could lead to the commercial viability of the large‐

ISSN:0009-4536    

DOI:10.1002/jccs.200900137

出版商:WILEY‐VCH Verlag    

年代:2009

数据来源: WILEY