Reactivity of anatase TiO(2) nanoparticles: the role of the minority (001) surface

Methanol adsorption on clean and hydrated anatase TiO(2)(001)-1 x 1 is studied using density functional theory calculations and first principles molecular dynamics simulations. It is found that (i) dissociative adsorption is favored on clean TiO(2)(001) at both low and high methanol coverages; (ii) on the partially hydrated surface, methanol dissociation is not affected by the coadsorbed water and can still occur very easily; (iii) the dissociative adsorption energy of methanol is always larger than that of water under similar conditions. This implies that water replacement by methanol is energetically favored, in agreement with recent experimental observations on colloidal anatase nanoparticles.     

Isoelectric focusing nonporous silica reversed-phase high-performance liquid chromatography/electrospray ionization time-of-flight mass spectrometry: a three-dimensional liquid-phase protein separation method as applied to the human erythroleukemia cell-line

A liquid-phase three-dimensional protein separation method has been developed that is used to separate the cytosolic fraction of a HEL cell lysate via isoelectric focusing (IEF), nonporous silica (NPS) reversed-phase high-performance liquid chromatography (RP-HPLC) and electrospray ionization time-of-flight mass spectrometry (ESI-TOFMS), respectively. Several hundred unique protein molecular weights were observed in a pI range from 4.8 to 8.5 and a mass range from 5 to 85 kDa. Proteins were positively identified by analysis of the pI (+/-0.5 pI units), an intact protein molecular weight (+/-150 ppm), and peptide mass mapping results. Using the molecular weight (MW) and peptide mapping results of identified proteins it was possible to characterize their posttranslational (PTMs) and/or sequence modifications. PTMs were detected on both forms of cytosolic actin, heat shock 90 beta, HINT and alpha-enolase. Sequence modifications or conflicts were observed for beta-and gamma-actin, ATP beta-synthase and heat shock 90 beta. IEF-NPS-RP-HPLC/ESI-TOFMS was used to determine experimental pI, MW and relative hydrophobicity values for each protein detected. This data was used to generate a 2-D pI-MS protein map, where proteins are displayed according to their pI and molecular weight. Protein molecular weight peaks are represented as bands in the 2-D pI-MS image where the gray scale of each band is proportional to the intensity of the protein molecular weight peak. In addition, a third hydrophobicity dimension (%B) was added as the % acetonitrile elution to generate a 3-D pI-MS-%B plot where each protein can be tagged according to three parameters.     

金属－助剂相互作用对SiO_2载铑催化剂化学吸附的影响──Ⅱ．Rh－V／SiO_2催化剂

由ＲｈＣｌ_３·ｘＨ_２Ｏ制备了不同Ｒｈ含量的Ｒｈ／ＳｉＯ_２和Ｒｈ－Ｖ／ＳｉＯ_２催化剂，采用化学吸附和原位ＴＰＤ－ＩＲ方法考察钒助剂对Ｒｈ／ＳｉＯ_２催化剂在常温和高温的Ｈ_２和ＣＯ化学吸附的影响。结果再次表明：１）不同Ｒｈ中心对Ｈ_２和ＣＯ的化学吸附性能不同，钒助剂对不同Ｒｈ中心的Ｈ_２和ＣＯ吸附的影响也不同。Ｈ_２主要吸附在Ｒｈ~Ⅱ和Ｒｈ~Ⅲ中心上，而在Ｒｈ~Ⅰ中心上的吸附弱。２）Ｒｈ－钒助剂的强相互作用主要是Ｒｈ~Ⅱ和Ｒｈ~Ⅲ与钒助剂之间的相互作用，Ｈ_２吸附受到比ＣＯ吸附更强烈的抑制。钒助剂对Ｒｈ／ＳｉＯ_２的Ｈ_２和ＣＯ吸附性能的影响可用覆盖模型解释。     

Construction of a 2,6-difunctionalized 2-methyl-2H-1-benzopyran library by using a solid-phase synthesis protocol

[reaction: see text] A library containing 1200 analogues of 2,6-difunctionalized 2-methyl-2H-1-benzopyran was constructed by using a solid-phase synthesis protocol. Polymer-bound 6-amido-, 6-sulfonamido-, and 6-uredo-functionalized 2-hydroxymethyl-2-methylbenzopyrans 10 were prepared as part of a first-generation diversification step by employing reactions of respective acid halides, sulfonyl chlorides, and isocyanates with the amine precursor 7. Transformations of the resin-bound intermediates 10 by reactions with alkyl and acid halides were then used to produce a diverse series of 2,6-difunctionalized 2-methyl-2H-1-benzopyran analogues 12 and 14.     

氯代十六烷基吡啶存在下钯与1，4－双肼酞嗪新显色反应的研究

本文研究了１，４－双肼酞嗪（ＤＨＰＨ）与钯的配合显色反应，在阳离子型表面活性剂氯代十六烷基吡啶存在下，在０．１～０．２ｍｏｌ／ＬＨＣｌ溶液中，试剂与钯形成１：１的稳定的黄绿色配合物，最大吸收峰在４００ｎｍ处，表观摩尔吸光系数为２．６×１０￣４，钯量在０～５０μｇ／２５ｍＬ范围内股从比尔定律，方法简便快速，选择性好，已用于催化剂中钯的测定，结果满意。     

Preparation and structural characterization of the hexatungsten cluster complex (EDTEH)2[W6(μ3-Cl)8Cl6], (EDTEH=(MeO2CCH2)2N(H)CH2CH2N(CH2CO2Me)2+

The hexanuclear tungsten cluster complex [W₆(₃-Cl)₈Cl₆]^2–,1 was isolated as a salt of the cation (MeO₂CCH₂)₂N(H)CH₂CH₂N(CH₂CO₂Me)₂₊, EDTEH⁺, by crystallization from methanol solvent of the product obtained from the reaction of (H₃O)₂[W₆(₃-Cl)₈Cl₃] with the disodium salt of ethylenediaminetetraacetic acid. The compound was charcterized by single-crystal X-ray diffraction analysis. The cluster anion contains an octahedral arrangement of six tungsten atoms with chloride ligands bridging the eight triangular faces of the cluster and one chloride ligand terminally coordinated to each of the six tungsten atoms. The cation (EDTEH)⁺ achieves its positive charge by protonation of one of the nitrogen atoms. Crystal data: space group = P2₁/a,a=10.689(2) Å,b=22.931(6) Å,c=12.093(3) Å, =98.41(2)°,Z=2, 2476 reflections,R=0.028.     

铜（Ⅱ）锌（Ⅱ）－氟哌酸体系电化学行为及示波极谱法研究

铜（Ⅱ）和锌（Ⅱ）分别在０．１ｍｏｌ／ＬＫＨ＿２ＰＯ＿４－Ｎａ＿２ＨＰＯ＿４缓冲溶液（ｐＨ６．５）和０．２５ｍｏｌ／ＬＮＨ＿４Ｃｌ溶液中，与氟哌酸形成良好的络合吸附波，峰电位分别为－０．２６Ｖ和－１．２８Ｖ（ｖｓ；ＳＣＥ）；络合比分别为１：３和１：２；峰电流与铜（Ⅱ）和锌（Ⅱ）的浓度均在４．０×１０￣（－７）～５．０×１０￣（－６）ｍｏｌ／Ｌ范围内呈线性关系，检测限分别为７．０×１０￣（－８）和５．０×１０￣（－８）ｍｏｌ／Ｌ。用线性扫描和循环伏安法等手段研究体系的行为，表明均具吸附性，而铜（Ⅱ）－氟哌酸体系属络合物中铜（Ⅱ）的两电子还原的可逆过程。     

A New Brominated Phenylpropylaldehyde and its Dimethyl Acetal from Red Alga Rhodomela confervoides

A new brominated phenylpropylaldehyde and its dimethyl acetal together with a new natural brominated phenol were isolated from Rhodomela confervoides. Their structrues were elucidated as 2-methyl-3-(2,3-dibromo-4,5-dihydroxyphenyl)propylaldehyde, 2-methyl-3-(2,3-di-bromo-4,5-dihydroxyphenyl) propylaldehyde dimethyl acetal and 3-bromo-4,5-dihydroxybenzoic acid methyl ester by spectroscopic techniques including IR, HRFABMS, 1D and 2DNMR experiments.     

Plasmid DNA isolation using amino-silica coated magnetic nanoparticles (ASMNPs)

A simple and efficient approach for the rapid isolation of plasmid DNA from crude cell lysates has been described. The approach took advantage of the amino-modified silica coated magnetic nanoparticles (ASMNPs) with positive zeta potential at neutral pH and superparamagnetism under the external magnetic fields. As a demonstration, the pEGFP-N3 plasmid has been concentrated and isolated from the E. coli DH5α transformed with pEGFP-N3 plasmid through electrostatic binding between the positive charge of the amino group of ASMNPs and the negative charge of the phosphate groups of the plasmid DNA. Then the pEGFP-N3 plasmid has been released easily and quickly from the pEGFP-N3 plasmid-ASMNPs complexes with 3 M NaCl. The entire procedure could be carried out by the aid of external magnetic fields in 15 min and eliminate the need of phenol, cesium chloride gradients or other noxious reagents and complexes operation. Moreover, the pEGFP-N3 plasmid obtained by this approach retains biological activity that can be suitable for restriction enzyme digestion and cells transfection with expression of green fluorescence protein.     

Highly efficient, one-step macrocyclizations assisted by the folding and preorganization of precursor oligomers

Highly efficient, one-step macrocyclizations leading to the formation of macrocyclic hexa(aramides) in high yields (69-82%) are described. The one-step macrocyclizations were facilitated by the preorganization or folding of the backbones of uncyclized precursors in the course of macrocyclization. The preorganization of backbones was achieved by the presence of localized three-centered hydrogen bonds that were adopted in the design of a class of closely related, backbone-rigidified foldamers. The macrocyclization involved reactions between diacid chloride 1 and diamine 2. The crude reaction mixtures and products were conveniently examined by mass spectrometric method (MALDI-TOF). Compared to most traditional one-step macrocyclizations that usually require high dilution conditions and often lead to very low overall yields of the desired products, cyclic hexamers 3 were obtained as the overwhelmingly major product under a variety of reaction conditions, suggesting the generality of this approach.