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1.
Narottam Gharah Michael G. B. Drew Ramgopal Bhattacharyya 《Transition Metal Chemistry》2009,34(5):549-557
[MoO(O2)2(PyCOXH)(H2O)] and PMePh3[MoO(O2)2(PyCO)] (PyCOXH = Pyridine-2-carboxaldoxime and PyCOH = Pyridine-2-carboxylic acid) have been synthesized. Both complexes
have been characterized by physico-chemical and spectroscopic methods; in addition, the carboxylate complex has been structurally
characterized by X-ray crystallography. The carboxylate complex is a more efficient catalyst than the oxime complex for epoxidation
of olefins and shows excellent catalytic activity for the substrates: cyclooctene, cinnamyl alcohol, allyl alcohol and 1-hexene.
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2.
The kinetics of oxidation of the anti-ulcer drug, ranitidine hydrochloride (RNH) by diperiodatocuprate(III) (DPC) in alkaline
medium was studied spectrophotometrically. The reaction exhibits 1:2 stoichiometry (ranitidine:DPC). The reaction is of first
order in [DPC] and has less than unit order in [RNH] and negative fractional order in [alkali]. The involvement of free radicals
was observed in the reaction. The oxidation has been found to proceed via a DPC-ranitidine complex, which decomposes slowly
in a rate-determining step followed by other fast steps to give the products, which were identified as ranitidine sulfoxide
by spot test and spectroscopic studies.
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3.
Zhe Hong 《Transition Metal Chemistry》2008,33(6):797-802
A pair of structurally similar thiocyanato-bridged dinuclear Cu(II) complexes derived from the Schiff bases 2,4-dibromo-6-[(2-diethylaminoethylimino)methyl]phenol
and 4-nitro-2-[(2-ethylaminoethylimino)methyl]phenol has been prepared and characterized by physico-chemical and spectroscopic
methods. Each Cu atom is five-coordinate in a square-pyramidal geometry, with one O and two N atoms of one Schiff base ligand
and one N atom of a bridging thiocyanate ligand defining the basal plane, and with one terminal S atom of another bridging
thiocyanate ligand occupying the apical position. Antimicrobial activities of the Schiff bases and the two complexes have
been tested.
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4.
Rabab Tayyem Reema Tayyem Naji Najib Jaafar Tamimi Mukhtar Shihabeddin 《Accreditation and quality assurance》2008,13(8):473-477
As contract research organizations are now familiar with GXPs and have become more popular for conducting bioequivalence studies,
it is very important that the sponsor has the assurance that the study has been conducted not only to the highest standard
of science but also in compliance with regulatory requirements. The dynamic role of quality personnel requires alert knowledgeable
people to recognise all the issues which arise and take the proper actions—experienced persons can detect and rectify these.
On the basis of equality, for quality system personnel and scientists a firm grasp of regulatory science is needed to succeed.
It must be remembered that compliance is monitored by adherence to regulatory standards, whereas the regulatory bodies review
the appropriately implemented regulatory science principles.
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5.
Sander LC Putzbach K Nelson BC Rimmer CA Bedner M Thomas JB Porter BJ Wood LJ Schantz MM Murphy KE Sharpless KE Wise SA Yen JH Siitonen PH Evans RL Nguyen Pho A Roman MC Betz JM 《Analytical and bioanalytical chemistry》2008,391(6):2023-2034
A suite of three dietary supplement standard reference materials (SRMs) containing bitter orange has been developed, and the
levels of five alkaloids and caffeine have been measured by multiple analytical methods. Synephrine, octopamine, tyramine,
N-methyltyramine, hordenine, total alkaloids, and caffeine were determined by as many as six analytical methods, with measurements
performed at the National Institute of Standards and Technology and at two collaborating laboratories. The methods offer substantial
independence, with two types of extractions, two separation methods, and four detection methods. Excellent agreement was obtained
among the measurements, with data reproducibility for most methods and analytes better than 5% relative standard deviation.
The bitter-orange-containing dietary supplement SRMs are intended primarily for use as measurement controls and for use in
the development and validation of analytical methods.
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6.
The clusters, up to four monomers, of the interhalogen derivatives (FCl, FBr, and ClBr) have been studied by means of ab initio
and DFT methods, up to MP2/aug-cc-pVTZ computational methods. Two dispositions, linear and cyclic, of the clusters have been
studied. Cooperative effects in the geometry, energy, and electron density have been observed in the linear and cyclic dispositions
of these clusters. The Natural Energy Decomposition Analysis shows that the main source of the interaction corresponds to
the polarization term.
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7.
Jayapalan Kasthuri Jayadevan Santhanalakshmi Nagappan Rajendiran 《Transition Metal Chemistry》2008,33(7):899-905
The oxidative coupling of phenols with 4-aminoantipyrine (AmNH2) has been studied by UV–visible spectroscopy using platinum nanoparticles as catalyst. The rate of antipyrilquinoneimine
dye formation depends on the nature of substrates, temperature, pH, and the use of microheterogeneous media such as sodium
dodecylsulphate (SDS), cetyl trimethylammonium bromide (CTAB) and Triton X-100 (TX-100). The reactivity trend observed for
differently substituted phenols follows the order: 3,5-dimethylphenol > phenol > o-chlorophenol > o-nitrophenol. The rate of dye formation is greater at acid pH than at basic pH and the optimum pH is 5.4. A reaction pathway
is proposed, involving the activation of o-chlorophenol with AmNH2 by metal nanoparticles and concomitant reactions of free radicals. Transmission electron microscopy results show that the
particle size is 20 nm for the platinum nanoparticles involved in catalysis.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
8.
Narottam Gharah Krishna Chowdhury Monika Mukherjee Ramgopal Bhattacharyya 《Transition Metal Chemistry》2008,33(5):635-642
A green heteropolyblue compound, (PPh4)4[PMo12O40] · 3DMF(1), has been synthesized from MoO3, H2O2 and H3PO4 in acetylacetone medium and crystallized from N,N-dimethylformamide. Compound 1 was characterized by analytical and spectroscopic methods, and X-ray structure analysis. The compound is a one-electron paramagnet
and shows a featureless and cubic EPR spectrum with <g> = 1.95 in DMF glass. The complex shows a Mo(V)–Mo(IV) couple, which
has been studied by cyclic voltammetric and coulometric methods. The compound acts as an efficient olefin epoxidation catalyst
with H2O2 as oxidant and NaHCO3 as co-catalyst.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
9.
Karen A. Rossi Akbar Nayeem Carolyn A. Weigelt Stanley R. Krystek Jr. 《Journal of computer-aided molecular design》2009,23(7):411-418
The success of structure-based drug design relies on accurate protein modeling where one of the key issues is the modeling
and refinement of loops. This study takes a critical look at modeled loops, determining the effect of re-sampling side-chains
after the loop conformation has been generated. The results are evaluated in terms of backbone and side-chain conformations
with respect to the native loop. While models can contain loops with high quality backbone conformations, the side-chain orientations
could be poor, and therefore unsuitable for ligand docking and structure-based design. In this study, we report on the ability
to model loop side-chains accurately using a variety of commercially available algorithms that include rotamer libraries,
systematic torsion scans and knowledge-based methods.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
10.
Sen Hou Xinxin Li Xiaoyu Li Xi-Zeng Feng Rui Wang Chen Wang Lei Yu Ming-Qiang Qiao 《Analytical and bioanalytical chemistry》2009,394(3):783-789
Surface wettability conversion with hydrophobins is important for its applications in biodevices. In this work, the application
of a type I hydrophobin HGFI in surface wettability conversion on mica, glass, and poly(dimethylsiloxane) (PDMS) was investigated.
X-ray photoelectron spectroscopy (XPS) and water-contact-angle (WCA) measurements indicated that HGFI modification could efficiently
change the surface wettability. Data also showed that self-assembled HGFI had better stability than type II hydrophobin HFBI.
Protein patterning and the following immunoassay illustrated that surface modification with HGFI should be a feasible strategy
for biosensor device fabrication.
Figure A hydrophobin HGFI has been applied into surface wettability conversion for protein immobilization
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
11.
A novel ruthenium(II) porphyrin complex, [Ru(phen)2MPyTPP] (phen = phenanthroline, MPyTPP = mono-(3′-Pyridine)-10,15,20-triphenyl porphyrin), has been prepared and characterized by elemental analysis, ESI-MS and NMR methods.
The interaction of the complex with G-quadruplex DNA has been studied by spectroscopy, and the results have shown that [Ru(phen)2MPyTPP] can bind to G-quadruplex d(TTAGGG)4 with high affinity. In the presence of d(TTAGGG)4, the characteristic Soret and intra-ligand (IL) transitions in the UV–Vis spectrum of the complex exhibit hypochromism of
25% (Δλ = 6 nm) and 18% (Δλ = 1 nm), respectively. The intrinsic binding constant was calculated according to the decay of
the Soret band as 3.02(±0.08) × 106 M−1. The positive signal of d(TTAGGG)4 in its circular dichroism spectra was clearly decreased in the presence of the complex, indicating the conformation of the
G-quadruplex was severely disturbed by the ruthenium(II) complex.
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12.
Fyaz M. D. Ismail Michael G. B. Drew Suppiah Navaratnam Roger H. Bisby 《Research on Chemical Intermediates》2009,35(4):363-377
Free radicals from one-electron oxidation of the antimalarial drug pyronaridine have been studied by pulse radiolysis. The
results show that pyronaridine is readily oxidised to an intermediate semi-iminoquine radical by inorganic and organic free
radicals, including those derived from tryptophan and acetaminophen. The pyronaridine radical is rapidly reduced by both ascorbate
and caffeic acid. The results indicate that the one-electron reduction potential of the pyronaridine radical at neutral pH
lies between those of acetaminophen (707 mV) and caffeic acid (534 mV). The pyronaridine radical decays to produce the iminoquinone,
detected by electrospray mass spectrometry, in a second-order process that density functional theory (DFT) calculations (UB3LYP/6-31+G*)
suggest is a disproportionation reaction. Important calculated dimensions of pyronaridine, its phenoxyl and aminyl radical,
as well as the iminoquinone, are presented.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
13.
Vito Capriati Saverio Florio Renzo Luisi Biagia Musio Ibon Alkorta Fernando Blanco José Elguero 《Structural chemistry》2008,19(5):785-792
A DFT (B3LYP/6-311++G(d,p) study of a series of N-H, N-methyl and N-propyl aziridines and their C-lithium derivatives has been carried out in order to explore their configurational as well as their NMR properties (1H and 13C). The results agree fairly well with experimental observations [Org Lett 9:1263, 2007 and J Org Chem 73, 2008 (73:3197)]
and reveal the existence of lithium-N(lone pair) and lithium C(aromatic) interactions.
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14.
Zi Le Hua Jian Hua Gao Wen Bo Bu Ling Xia Zhang Hang Rong Chen Jian Lin Shi 《Journal of Sol-Gel Science and Technology》2009,50(1):22-27
Under typical dilute reactant compositions (3 ~ 5 wt% of surfactant template concentration) and conventional hydrothermal
conditions for mesoporous materials synthesis, successful preparation of hierarchically macro/mesoporous silica monoliths
was reported in this paper. The resultant materials were characterized by a series of techniques including powder X-ray diffraction,
N2 adsorption–desorption, SEM, TEM/EDS, and Hg porosimetry. A new kind of stable and hierarchically porous pure silica monoliths
was confirmed, which are featured with highly ordered mesoporous structures, rod-shaped unit particles, large specific surface
area of 492 m2/g, continuous macropores of about 4.0 μm in size and high macropore volume of about 13.1 cm3/g. Moreover, using the resultant silica monoliths as hard templates, carbon monoliths have been successfully replicated,
which inherit the structural characters of parent silica materials.
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15.
Xiaoshu Qu Lin Xu Yanyan Yang Fengyan Li Weihua Guo Liping Jia Xizheng Liu 《Structural chemistry》2008,19(5):801-805
A novel three-dimensional (3-D) supramolecular assembly of organic bicapped heptamolybdate Na(NH4)[C13N2H16]2[Mo7O24]·8H2O has been hydrothermally synthesized and structurally characterized by single-crystal X-ray diffraction, IR spectra, elemental
analysis, and thermogravimetric analysis (TGA). X-ray analyses show that compound 1 represent a novel 3-D extended supramolecular “host” networks with 1-D channels encapsulating flexible cation “guests”.
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16.
Jeffery S. Edmiston Jason W. Flora Mariano J. Scian Guoya Li Gaurav S. J. B. Rana Timothy B. Langston Tapas K. Sengupta Willie J. McKinney 《Analytical and bioanalytical chemistry》2009,394(6):1609-1620
Phosphorylation is the most widely studied posttranslational modification (PTM) and is an important regulatory mechanism used
during cellular responses to external stimuli. The kinases and phosphatases that regulate protein phosphorylation are known
to be affected in many human diseases. Cigarette smoking causes cardiovascular disease (CVD). Endothelial cells play a pivotal
role in CVD initiation and development; however, there have been limited investigations of the specific signaling cascades
and protein phosphorylations activated by cigarette smoke in endothelial cells. The purpose of this research was to better
understand the differential protein phosphorylation in endothelial cells stimulated with extracts of cigarette smoke total
particulate matter (CS-TPM) in vitro. Human microvascular endothelial cells were exposed in vitro to CS-TPM at concentrations
that were shown to cause endothelial cell dysfunction. The phosphorylated proteins were isolated using phosphoprotein-specific
chromatography, followed by enzymatic digestion and nano-flow capillary liquid chromatography (ncap-LC) coupled to high resolution
mass spectrometry. This study putatively identified 94 proteins in human microvascular endothelial cells that were differentially
bound to a phosphoprotein-specific chromatography column following exposure to CS-TPM suggesting differential phosphorylation.
Pathway analysis has also been conducted and confirmations of several observations have been made using immunoaffinity-based
techniques (e.g., Western blotting).
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17.
Two isostructural mononuclear complexes with the formula [MIIIL(N3)(OH2)] × 1/2N2 (M = Mn for (1) and Fe for (2); H2L = N,N′-bis(3-ethoxysalicylidene)-1,2-propanediamine) have been synthesized and characterized by physico-chemical and spectroscopic
methods. Each compound consists of a mononuclear complex molecule and half of a nitrogen molecule of crystallization. Each
metal atom in the complexes has a slightly distorted octahedral geometry, coordinated by two nitrogen and two phenolic donors
of L, the oxygen atom of the water molecule, and the nitrogen atom of the azide group. Determination by GC/MS analysis indicated
that complex (1) has no catalytic property for the dioxygen oxidization of cyclohexene, but complex (2) has good properties.
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18.
Enhanced recognition of non-complementary hybridization by single-LNA-modified oligonucleotide probes 总被引:1,自引:0,他引:1
XianYu Piao Ying Yan Jing Yan YiFu Guan 《Analytical and bioanalytical chemistry》2009,394(6):1637-1643
Locked nucleic acid (LNA) is a deoxyribonucleotide analogue with an unusual ‘locked’ furanose conformation. LNA-modified oligonucleotide
probes have demonstrated an enhanced binding affinity towards their complementary strands; however, their potential to discriminate
non-complementary hybridization of mismatches has not been explored. In this study, we investigated the effect of the chemical
nature of LNA nucleobases on the hybridization stability and the capability of LNA-modified oligonucleotides to discriminate
the LNA:DNA mismatched base pairs. It was observed that LNA modification indeed improves the discrimination capability of
oligonucleotides by increasing the melting temperature differences between the complementary duplexes and hybrids containing
mismatches. Particularly, LNA purines offer a greater potential to recognize the mismatches than LNA pyrimidines and DNA purines.
Real-time PCR experiments further confirmed that LNA modifications at the 3′-end are more effective. The results and conclusions
in this study provide useful information for hybridization-based nucleic acid analysis where designing sound oligonucleotide
probes is crucial to the success of the analyses.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
19.
Nagarajan Sathya Arumugam Manimaran Gunasekaran Raja Periyasamy Muthusamy Kandasamy Deivasigamani Chinnasamy Jayabalakrishnan 《Transition Metal Chemistry》2009,34(1):7-13
New mononuclear ruthenium(III) Schiff base complexes of the type [RuX2(EPh3)(L)] (X = Cl or Br; E = P or As; L = monobasic tridentate Schiff base derived from o-aminophenol or o-aminothiophenol with ethylacetoacetate or ethylbenzoylacetate) have been synthesized. The Schiff base ligands chelate to ruthenium
through O, N, and O/S by dissociation of the phenolic proton/thiophenolic proton forming chelate rings. These complexes have
been characterized by physico-chemical and spectroscopic methods. Cyclic voltammetric data of all the complexes showed Ru(III)/Ru(IV)
oxidation and Ru(III)/Ru(II) reduction within the range of 0–1.5 V and 0 to −1.5 V with respect to Ag/AgCl, respectively.
The complexes were tested as catalysts in the oxidation of alcohols using molecular oxygen at ambient temperature, and also
in C–C coupling reactions.
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20.
Lian Chen Fei-Long Jiang Ning Li Wen-Tao Xu Mao-Chun Hong 《Journal of Cluster Science》2008,19(4):591-600
Single crystals of [W11Ni1P1O39(Hbpy)](H2bpy)2 · 4.25H2O (1) and (W11Zn1P1O39)(H2bpy)2(Hbpy) · 1.5H2O (2) have been hydrothermally synthesized at 160 °C and both characterized by IR, elemental and single-crystal structural analyses.
Compound 1 has a ladder-like chain structure by hydrogen bonding interactions, whereas 2 contains an unprecedented chain of Keggin polyoxotungstates by oxo-bridges and form a 2-D layer via hydrogen bonds.
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