Synthesis of Two Novel Rhenium（I） Bipyridyl Photosensitive Dyes

Two novel rhenium(I) 2, 2′-bipyridyl complexes, [(4,4′-di-COOEt-bipy) Re(CO)3 (NCCH3)PF6] and [(4,4′-di-COOEt-bipy) Re (CO)3 (NCS)], a model complex [(4,4′-di-COOEt-bipy) Re (CO)3 (pyridine)PF6], were synthesized. Their ground state electronic spectra and emission spectra were measured in acetonitrile. The MLCT absorption maximum of the complex exhibited a considerable red shift as the ligand changed from pyridine to CNCH3, or SCN.     

MoO3/TiO2-Al2O3催化剂表面结构的LRS研究

负载型Mo和Co-Mo催化剂由于工业上的广泛应用,多年来一直是催化工作者的重要研究课题.工业上应用的Mo和Co-Mo催化剂多以活性Al_2O_3和SiO_2-Al_2O_3为载体,近年来也有用TiO_2,ZrO_2和活性碳作为催化剂载体的研究报导.有关催化剂活性组分与载体之间相互作用对催化剂表面相结构和催化性能的影响方面研究已引起人们的重视。我们多年来在金属-载体相互作用研究基础上,以石油加氢精制催化剂为应用背景,开     

Novel Water Soluble Fluorescent Trimethine Indocyanines Containing N-ρ-Carboxybenzyl Group

Indocyanine dyes as fluorescent labeling reagents have been used in bioanalysis1,2. Arylsulfonate indocyanine dyes 1d and 1e developed by Waggoner A. S. et al.3,4 have excellent fluorescent properties combined with good aqueous solubility, are a new generation of fluorescent label compounds for proteins, oligonucleotides and other compounds containing hydroxyl, mercaptol or primary amine groups5. However, photostability of these dyes has been a problem. Z. G. YAO et al.6 reported that p…     

Physico-chemical Characterization of Mo-Hβ Zeolite Catalysts

A series of Mo-impregnated Hβ samples, with MoO3 loading in Hβ zeolite in the mass fraction range of 0. 5%-6.0%, were studied by means of XRD and IR in order to characterize their structures. Mo/Hβ sampies‘ crystallinity almost linearly decreases with increasing the amount of MoO3 loaded, The IR spectra and XRD patterns suggest that the progressive destabilization of the Hβ zeolite structure is caused by increasing Mo loading in (MoO3 Hβ zeolite). During the calcination, Al2(MoO4)3 formed from the dealumination of Hβ zeolite, causes the substantially partial breakdown of the zeolite framework when the Mo loading in MoO3 Hβ is relatively high.     

Retention behaviour of carboxylic acid methyl esters in supercritical fluid chromatography

The study on retention behavior in supercritical fluid chromatography (SFC) is necessary to understand the mechanism of the various interactions in SFC. The retention of SFC in carboxylic acid methyl ester/polymethylsiloxane/CO2 system was studied systematically and the retention behavior of this kind of compounds under various typical operation conditions was described using the method of an alternative unified theory of chromatographic retention. The results illustrated that expression: Ink.= a + b/T + cp + dp/T + ep2/T can be used to describe quantitatively the retention behavior of carboxylic acid methyl ester/polymethylsiloxane/CO2 system in the ranges of reduced density from 0.549 to 1.411. It was also found that the entropy of solute in stationary phase is dependent on the density of supercritical fluid (SF) under typical operating conditions of SFC.     

Preparation and characterization of vanadium(IV) oxide supported on SBA-15 and its catalytic performance in benzene hydroxylation to phenol using molecular oxygen

Preparation of dispersed transition metal oxides catalyst with low oxidation state still remains a challenging task in heterogeneous catalysis.In this study,vanadium oxides supported on zeolite SBA-15 have been prepared under hydrothermal condition using V 2 O 5 and oxalic acid as sources of vanadium and reductant,respectively.The structures of samples,especially the oxidation state of vanadium,and the surface distribution of vanadium oxide species,have been thoroughly characterized using various techniques,including N 2-physisorption,X-ray diffraction(XRD),transmission electron microscopy(TEM),X-ray photoelectron spectroscopy(XPS),UV-visible spectra(UV-Vis) and UV-visible-near infrared spectra(UV-Vis-NIR).It is found that the majority of supported vanadium was in the form of vanadium(IV) oxide species with the low valence of vanadium.By adjusting hydrothermal treatment time,the surface distribution of vanadium(IV) oxide species can be tuned from vanadium(IV) oxide cluster to crystallites.These materials have been tested in the hydroxylation of benzene to phenol in liquid-phase with molecular oxygen in the absence of reductant.The catalyst exhibits high selectivity for phenol(61%) at benzene conversion of 4.6%,which is a relatively good result in comparison with other studies employing molecular oxygen as the oxidant.     

Isolation and Purification of Unstable Iridoid Glucosides from Traditional Chinese Medicine by Preparative High Performance Liquid Chromatography Coupled with Solid-phase Extraction

An efficient preparative method was successfully developed for isolation and purification of unstable components from medicinal plant extracts, using a combined method of preparative high performance liquid chro-matography(HPLC) and solid-phase extraction(SPE). The aim of this study was to obtain an effective method with high preparative efficiency and importantly to avoid the transformation of unstable compounds. The preparative HPLC system was based on an LC/MS controlled four-channel autopurification sys...     

AI-2 Key Enzyme S-Ribosylhomocysteinase from Strain Klebsiella pneumoniae CICC 10011 Producing 2,3-Butanediol

S-Ribosylhomocysteinase(LuxS) is the key enzyme in the synthetic pathway of a quorum sensing autoinducer AI-2. LuxS from a 2,3-butanediol produced strain Klebisella pneumoniae CICC 10011 was cloned and characterized. The luxS gene is composed of 540 bp with 172 amino acids encoded. The Km value for S-ribosylhomo- cysteine(SRH) was (27±1) umol/L, kcat was (0.112±0.004) s-1 and kcat/Km was 4.4×103 L umol-1·s-1 at 25 ℃. LuxS was activated by divalent metal ions, the highest activity was detected with Co2+ form...     

First-principles calculation of core-level binding energy shift in surface chemical processes

Combined with third generation synchrotron radiation light sources, X-ray photoelectron spectroscopy (XPS) with higher energy resolution, brilliance, enhanced surface sensitivity and photoemission cross section in real time found extensive applications in solid-gas interface chemistry. This paper reports the calculation of the core-level binding energy shifts (CLS) using the first-principles density functional theory. The interplay between the CLS calculations and XPS measurements to uncover the structures,...     

Modelling of multi-bodies in close proximity under water waves——Fluid resonance in narrow gaps

Viscous fluid model and potential flow model with and without artificial damping force(f=-μV,μ the damping coefficient and V the local averaging flow velocity) are employed in this work to investigate the phenomenon of fluid resonance in narrow gaps between multi-bodies in close proximity under water waves.The numerical results are compared with experimental data available in the literature.The comparison demonstrates that both the viscous fluid model and the potential flow model are able to predict the res...