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1.	Amirnasr, Mehdi, et al. (författare) Synthesis, characterization, and single crystal X-ray structures of [CoIII(acacen)(thioacetamide)2]ClO4 and [CoIII((BA)2en)(thioacetamide)2]PF6 - Solvatochromic properties of [CoIII(acacen)(thioacetamide)2]ClO4 2005 Ingår i: Canadian Journal of Chemistry. - 0008-4042 .- 1480-3291. ; 83:12, s. 2073-2081 Tidskriftsartikel (refereegranskat)abstract The trans-[CoIII(acacen)(ta)2]ClO4 (1) and trans-[CoIII((BA)2en)(ta)2]PF6 (2) complexes, where H2acacen = bis(acetylacetone)ethylenediimine, H2(BA))2en = bis(benzoylacetone)ethylenediimine, and ta = thioacetamide, have been synthesized by a solid-state method, and characterized by elemental analyses, IR, UV-vis, and 1H NMR spectroscopy. The crystal and molecular structures of 1 and 2 were determined by X-ray crystallography. Both compounds crystallize in the monoclinic space group P2/n. The ClO4 and PF6 ions are both disordered, ClO4 on a twofold axis in 1 and PF6 on an inversion center in 2. Also bridging N-CH2-CH2-N is disordered in both compounds. The octahedral coordination of Co(III) is slightly distorted in both cases. The thioacetamide ligands are S-bonded and occupy the axial position. The IR, UV-vis, and 1H NMR spectra of the two complexes and their solvatochromic properties are also discussed. The longest wavelength absorption that appears at 517 nm for 1 and at 528 nm for 2 in chloroform is solvent dependent, and is assigned as a metal-mediated ligand-to-ligand charge transfer (LLCT).
2.	Armstrong, Emily J., et al. (författare) A ground-state complex between methyl viologen and the fluorescent whitening agent 4,4 '-bis(2-sulfostyryl)-biphenyl disodium salt : a fluorescence spectroscopy study 2021 Ingår i: Canadian journal of chemistry (Print). - : Canadian science publishing. - 0008-4042 .- 1480-3291. ; 99:7, s. 563-569 Tidskriftsartikel (refereegranskat)abstract This study explores the quenching of the dianionic fluorescent whitening agent, NFW, by various substances, including methyl viologen (MV), in water and in the presence of beta-cyclodextrin (beta-CD). Results of a fluorescence spectro-scopic examination of the beta-CD-NFW system are presented. It was found that NFW forms a 1:1 inclusion complex with b-CD with an association constant of 2540 +/- 380 M-1. The included NFW fluorescent state is protected by the beta-CD cavity from a range of water-based quenchers (neutral, anionic, and cationic). Quenching proceeds near the diffusion-controlled limit in water for the quenchers tested with the exception of the dicationic MV. Methyl viologen is an extremely efficient quencher of NFW fluorescence with a nominal K-SV similar to 5.0 x 10(3) M-1 in water alone, corresponding to a nominal k(q) of similar to 4 x 10(12) M-1 s(-1), which exceeds the diffusion-controlled limit in this solvent. The quenching efficiency of MV is strongly suppressed in the presence of 10 mM beta-CD (K-SV = 105 +/- 12 M-1) and in the presence of NaCl (K-SV = 106 +/- 9 M-1 at 0.5 M salt). In the absence of CD or salt, there is a strong contribution from static quenching in the MV system; the presence of these additives suppresses the static quenching. Various results suggest the static quenching is due to formation of a ground-state complex between the dianion NFW and the dication MV.
3.	Atzori, Alessio, et al. (författare) Base sequence specificity of counterion binding to DNA : what can MD simulations tell us? 2016 Ingår i: Canadian journal of chemistry (Print). - : Canadian Science Publishing. - 0008-4042 .- 1480-3291. ; 94:12, s. 1181-1188 Tidskriftsartikel (refereegranskat)abstract Nucleic acids are highly charged biopolymers whose secondary structure is strongly dependent on electrostatic interactions. Solvent molecules and ions are also believed to play an important role in mediating and directing both sequence recognition and interactions with other molecules, such as proteins and a variety of ligands. Therefore, to fully understand the biological functions of DNA, it is necessary to understand the interactions with the surrounding counterions. It is well known that monovalent counterions can bind to the minor groove of DNA with consecutive sequences of four, or more, adenine and thymine (A-tracts) with relatively long residence times. However, much less is known about their binding to the backbone and to the major groove. In this work, we used molecular dynamics simulations to both investigate the interactions between the backbone and major groove of DNA and one of its physiological counterions (Na+) and evaluate the relationship between these interactions and the nucleotide sequence. Three dodecamers, namely CGAAAATTTTCG, CGCTCTAGAGCG, and CGCGAATTCGCG, were simulated using the Toukan-Rahman flexible SPC water model and Smith and Dang parameters for Na+, revealing a significant sequence dependence on the ion binding to both backbone and major groove. In the absence of experimental data on the atomistic details of the studied interactions, the reliability of the results was evaluated performing the simulations with additional sets of potential parameters for ions and solvent, namely the A. qvist or the Joung and Cheatham ion parameters and the TIP3P water model. This allowed us to evaluate the results by verifying which features are preserved independently from the parameters adopted.
4.	Brinkmann, Andreas, et al. (författare) Estimating internuclear distances between half-integer quadrupolar nuclei by central-transition double-quantum sideband NMR spectroscopy 2011 Ingår i: Canadian journal of chemistry (Print). - 0008-4042 .- 1480-3291. ; 89:7, s. 892-899 Tidskriftsartikel (refereegranskat)abstract We demonstrate the estimation of homonuclear dipolar couplings, and thereby internuclear distances, between half-integer spin quadrupolar nuclei by central-transition (CT) double-quantum (2Q) sideband nuclear magnetic resonance (NMR) spectroscopy. It is shown that the rotor-encoded sideband amplitudes from CT 2Q coherences in the indirect dimension of the two-dimensional NMR spectrum are sensitive probes of the magnitude of the homonuclear dipolar coupling, but are significantly less affected by other NMR parameters such as the magnitudes and orientations of the electric field gradient tensors. Experimental results of employing the R2(2)(1)R2(2)(-1) recoupling sequence to the (11)B spin pair of bis(catecholato)diboron resulted in an estimation of the internuclear B-B distance as (169.6 +/- 3) pm, i.e., with a relative uncertainty of +/- 2%, and in excellent agreement with the distance of 167.8 pm determined by single-crystal X-ray diffraction.
5.	Gao, Li, et al. (författare) Modification of the anticancer drug tamoxifen to avoid CYP2D6 polymorphism 2013 Ingår i: Canadian Journal of Chemistry-Revue Canadienne De Chimie. - : Canadian Science Publishing. - 0008-4042 .- 1480-3291. ; 91:9, s. 916-924 Tidskriftsartikel (refereegranskat)abstract The prodrug tamoxifen (TAM) is the most widely used drug to treat breast cancer, and is metabolised to the active 4-hydroxy derivatives dominantly by hepatic CYP2D6. However, the application to patients with different polymorphic CYP2D6 has been under debate, because the efficacy of TAM is suspected to be suppressed in patients who have diminished CYP2D6 activity, resulting in inadequate active metabolites. We here propose modified structures, such as 4-methylTAM, which is highly possible to be activated by CYP3A, the most abundant CYP isoforms in the liver, whereby the genetic polymorphism of CYP2D6 is avoided. The diversity of CYP catalyzed metabolic paths for TAM and its derivatives are studied by quantum chemistry calculations on the reaction energies of the initial H atom abstraction steps. The ability of forming DNA adducts is compared through the formation enthalpy of the carbocation intermediate. The results suggest that the modified structures are safe with regard to forming DNA adducts and may be used as prodrugs in a wide range of patients, due to CYP3A, rather than CYP2D6, mediated activation.
6.	HAEBERLEIN, M, et al. (författare) CALCULATED ELECTROSTATIC POTENTIALS AND LOCAL SURFACE-IONIZATION ENERGIES OF PARA-SUBSTITUTED ANILINES AS MEASURES OF SUBSTITUENT EFFECTS 1992 Ingår i: Canadian journal of chemistry (Print). - UNIV NEW ORLEANS,DEPT CHEM,NEW ORLEANS,LA 70148. : NATL RESEARCH COUNCIL CANADA. - 0008-4042 .- 1480-3291. ; 70:8, s. 2209-2214 Tidskriftsartikel (refereegranskat)abstract Using an ab initio self-consistent-field molecular orbital approach, we computed 3-21G//STO-3G* and STO-5G//STO-3G* electrostatic potentials and average local ionization energies for 17 para-substituted anilines. Our results demonstrate that the most negative potentials (V(min)) and the local surface ionization energy minima (I(s,min)BAR) associated with the amine nitrogen lone pairs are highly sensitive indicators of the electron-donating and electron-attracting tendencies of the para substituents. We find excellent linear relationships between the 3-21G//STO-3G* amine nitrogen V(min) and I(S,min)BAR and the sigma(p)0 Hammett constants of the substituent X; the correlation coefficients are 0.99. Correlations of slightly lesser quality are shown to exist between V(min), I(S,min)BAR, and sigma(p)-, sigma(p), and pK(a). Estimates of previously unknown sigma(p)0 and pK(a) values are given. The presence of ring carbon I(S,min)BAR meta to the substituent X also provides a predictive capability for determining sigma(m) values.
7.	Hedin, Eva. M. K., et al. (författare) Selective reduction and chemical modification of oxidized lipase cysteine mutants 2002 Ingår i: Canadian journal of chemistry (Print). - : Canadian Science Publishing. - 0008-4042 .- 1480-3291. ; 80:6, s. 529-539 Tidskriftsartikel (refereegranskat)abstract Thirteen single-cysteine mutants of the 33 kDa fungal triacylglycerol lipase Thermomyces (formerly Humicola) lanuginosa lipase (TLL, EC 3.1.1.3) Were produced and characterized for the purpose of site-directed chemical modification with spectroscopic reporter groups. All cysteine mutants were found to be predominantly blocked by oxidation to disulfides with endogenous cysteine during production. The fraction of lipase molecules with free sulfhydryl groups was analyzed by labeling with N-biotinylaminoethyl methanethiosulfonate, followed by a novel dot-blot method based on biotin-streptavidin interactions. A non-invasive method for the reduction of the introduced cysteine was elaborated for this protein containing three native disulfide bridges. The site-specifically reduced TLL mutants were then labeled with the sulfhydryl-specific reagents 2-(5-dimethylaminonaphth-1-ylsulfonamido)ethyl methanethiosulfonate or (1-oxyl-2,2,5,5-tetramethyl-Delta(3)-pyrroline-3-methyl) methanethiosulfonate, and studied by fluorescence and electron spin resonance (ESR) spectroscopy.
8.	Lahmann, Martina, Docent i kemi, 1963-, et al. (författare) Investigation of the reactivity difference between thioglycoside donors with variant aglycon parts 2002 Ingår i: Canadian journal of chemistry (Print). - Univ Stockholm, Arrhenius Lab, Dept Organ Chem, S-10691 Stockholm, Sweden. : Canadian Science Publishing. - 0008-4042 .- 1480-3291. ; 80:8, s. 889-893 Tidskriftsartikel (refereegranskat)abstract The reactivity of perbenzoylated thioglycosides with various thiol aglycons has been compared and quantified using competitive glycosylation experiments. Methyl 2,3,4-tri-O-benzyl-alpha-D-glucopyranoside was employed as acceptor and DMTST as a promoter. The reactivity was found, as expected, to depend on the electron donating properties of the aglycon. Hence, the most reactive donor, the cyclohexyl thioglycoside, was found to be about three times as reactive as the thioethyl glycoside, which in turn was twice as reactive as the thiomethyl donor. The thiophenyl donor was even less reactive, whereas p-halophenyl donors were inert under the glycosylation conditions used - but could be activated using NIS-TfOH as promoter. Furthermore, it was found that galactosyl donors were three to four times more reactive than the corresponding glucosyl derivative. These results allowed the design of an orthogonal coupling between thioglycosides with the same protecting groups (benzoyls) but with different thiol aglycons.
9.	Lahmann, Martina, Docent i kemi, 1963-, et al. (författare) Synthesis of a polyphosphorylated GPI-anchor core structure 2002 Ingår i: Canadian journal of chemistry (Print). - : Canadian Science Publishing. - 0008-4042 .- 1480-3291. ; 80:8, s. 1105-1111 Tidskriftsartikel (refereegranskat)abstract Using a linear assembly approach a highly differentially protected derivative of the common GPI-anchor core structure (alpha-D-Man-(1-->6)-alpha-D-Man-(1-->2)-alpha-D-Man-(1-->4)-alpha-D-GlcNH(2)-(1-->6)-D-myo-inositol) has been synthesized. All mannose donors were prepared from a common thioglycoside precursor (1), and coupled to GlcN(3)-myo-inositol acceptor 5 in a linear five-step glycosylation-deprotection sequence in 49% overall yield, to give the key intermediate 10, with orthogonal temporary protecting groups at the 6", 2", 6', and 2 positions of the trimannoside motif and at the 1 and 2 positions of the inositol part. Consecutive removal of the temporary protecting groups in the trimannoside moiety followed by phosphorylation, gave a tetraphosphosphate derivative in 60% overall yield. Removal of a camphor acetal afforded a 1,2-inositol diol, which was converted to a 1,2-cyclic phosphate using commercial methyl dichlorophosphate (-->17, 95%). One-step deprotection using sodium in liquid ammonia afforded the target polyphosphorylated core structure 18 (60%), which will be tested for metabolic insulin action.
10.	Mancal, Tomas, et al. (författare) Transfer of vibrational coherence through incoherent energy transfer process in Forster limit 2014 Ingår i: Canadian Journal of Chemistry. - : Canadian Science Publishing. - 0008-4042 .- 1480-3291. ; 92:2, s. 135-143 Tidskriftsartikel (refereegranskat)abstract We study transfer of coherent nuclear oscillations between an excitation energy donor and an acceptor in a simple dimeric electronic system coupled to an unstructured thermodynamic bath and some pronounced vibrational intramolecular mode. Our focus is on the nonlinear optical response of such a system, i.e., we study both excited state energy transfer and the compensation of the so-called ground-state bleach signal. The response function formalism enables us to investigate a heterodimer with monomers coupled strongly to the bath and by a weak resonance coupling to each other (Forster rate limit). Our work is motivated by recent observation of various vibrational signatures in two-dimensional coherent spectra of energy-transferring systems including large structures with a fast energy diffusion. We find that the vibrational coherence can be transferred from donor to acceptor molecules provided the transfer rate is sufficiently fast. The ground-state bleach signal of the acceptor molecules does not show any oscillatory signatures, and oscillations in ground-state bleaching signal of the donor prevail with the amplitude, which is not decreasing with the relaxation rate.
11.	Oscarsson, K, et al. (författare) Solid phase assisted synthesis of HIV-1 protease inhibitors. Expedient entry to unsymmetrical substitution of a C-2 symmetric template 2000 Ingår i: Canadian journal of chemistry (Print). - 0008-4042 .- 1480-3291. ; 78:6, s. 829-837 Tidskriftsartikel (refereegranskat)abstract A solid phase synthesis has been developed leading up to unsymmetrical HIV-1 protease inhibitors that are not readily available by conventional solution phase chemistry (18a-g). To prepare these compounds the hydroxyl group of (1S,2R)-(-)-cis-1-phthalimido-2-indanol (3) was coupled to a Merrifield resin via a dihydropyrane linker. Cleavage of the phthalimido protecting group and reaction of the liberated amine with the bis-activated symmetrical diacid 15 resulted in the resin bound amide 16. Coupling of 16 with amino acids and amines followed by hydrolysis produced the desired unsymmetrical products 18a-g from which potent HIV-1 protease inhibitors were identified, e.g., 18e (k(i) = 0.1 nM), 18a (k(i) = 0.2 nM) and 18c (k(i) = 2 nM).
12.	Rajput, Vishal Kumar, et al. (författare) Galactose-amidine derivatives as selective antagonists of galectin-9 2016 Ingår i: Canadian Journal of Chemistry. - : Canadian Science Publishing. - 0008-4042 .- 1480-3291. ; 94:11, s. 936-939 Tidskriftsartikel (refereegranskat)abstract The family of galectin proteins involved in adhesion, growth regulation, immunity, and inflammatory events are important targets for development of small molecule antagonists. Here, N-sulfonyl amidine galactopyranoside derivatives obtained via a multicomponent reaction between galactose alkyne derivatives, sulfonyl azides, and amines were evaluated as antagonists of galectin-1,-2,-3,-4N (N-terminal domain),-4C (C-terminal domain),-8N,-9N, and-9C in a competitive fluorescence polarization assay. Highly selective compounds against galectin-9N with up to 30-fold improved affinity compared to the reference methyl β-d-galactopyranoside were identified. Molecular dynamics simulation suggested that the selectivity and affinity for galectin-9N originate from the N-sulfonyl amidine moieties forming tridentate hydrogen bonds to two asparagine side chains and one phenyl stacking edge-to-face to an arginine side chain. These selective galectin-9N antagonists are of significant value as chemical tools for studying galectin-9 biology and chemistry as well as possible starting structures for the discovery of galectin-9-targeting drugs influencing, e.g., immune regulation.
13.	Ross, Russell G., et al. (författare) Clathrate and other solid phases in the tetrahydrofuran–water system : thermal conductivity and heat capacity under pressure 1982 Ingår i: Canadian journal of chemistry (Print). - : Canadian Science Publishing. - 0008-4042 .- 1480-3291. ; 60:7, s. 881-892 Tidskriftsartikel (refereegranskat)abstract Solid phases in the tetrahydrofuran–water (THF–H2O) system were investigated in the temperature range 100–260 K and at pressures up to 1.5 GPa. Thermal conductivity, λ, and heat capacity per unit volume, ρcp, were measured, using the transient hot-wire method. We made measurements on solid phases having nominal compositions THF•17H2O, THF•7.1H2O, and THF•4.6H2O, which we refer to as phases α, β, and γ, respectively. Phase α is known to be a structure II clathrate hydrate, and λ for this phase was found to be similar to other crystalline solids which are glass-like in relation to their thermal properties. Low-energy excitations are known to be relevant to the properties of glass-like solids, and, in the case of phase α, were probably rotational vibrations of the THF guest molecules. Phase β was similar, and we inferred that it was probably a structure I clathrate hydrate. Phase γ behaved nearly like a normal crystal phase at low temperatures, but λ became almost independent of temperature near melting. At 1.1 GPa and 130 K, we found evidence that phase α transformed, on pressurization, to a metastable modification which may be a new high-density form of clathrate hydrate. The astrophysical implications of our results were mentioned briefly.
14.	Samec, Joseph S. M., et al. (författare) Efficient Ruthenium-Catalyzed Transfer Hydrogenation of Functionalized Imines by Isopropanol under Controlled Microwave Heating 2005 Ingår i: Canadian journal of chemistry (Print). - 0008-4042 .- 1480-3291. ; 83:6, s. 909-916 Tidskriftsartikel (refereegranskat)abstract Transfer hydrogenation of various functionalized imines by isopropanol catalyzed by [Ru(CO)(2)(Ph4C4CO)](2) (3) has been studied. The use of either an oil bath or controlled microwave heating in toluene led to an efficient procedure with high turnover frequencies and the product amines were obtained in high yields. An advantage with catalyst 3 over the conventional [Ru-2(CO)(4)(mu-H)(Ph4C4COHOCC4Ph4)] (1) is the absence of an initiation period, which results in a faster reaction with 3 as compared to 1.
15.	Schroeder, Megan D., et al. (författare) Synthesis of a fluorescent chemical probe for imaging of L-type voltage-gated calcium channels 2024 Ingår i: Canadian journal of chemistry (Print). - : Canadian Science Publishing. - 0008-4042 .- 1480-3291. ; 102:4, s. 180-186 Tidskriftsartikel (refereegranskat)abstract Herein, we report the synthesis of a chemical probe for real-time visualization of L-type voltage-gated calcium channels (LTCCs) using fluorescence microscopy. The probe, FluoBar2, is based on a barbiturate ligand selective for LTCCs. FluoBar2 contains the organic fluorophore 5-carboxyfluorescein and was synthesized in seven total steps with a 22% overall yield.
16.	Shaw, Dawn M., et al. (författare) Theoretical X-ray absorption investigation of the uniaxial compression of hexagonal graphite 2007 Ingår i: Canadian journal of chemistry (Print). - 0008-4042 .- 1480-3291. ; 85:10, s. 837-842 Tidskriftsartikel (refereegranskat)abstract The X-ray absorption (XAS) and powder X-ray diffraction (XRD) spectra for the intermediate structures along uniaxial c-axis compression of hexagonal graphite are studied with the first-principles pseudopotential plane wave method. Comparison with experiment is made whenever results are available. A transformation from graphite to a new carbon phase was observed in the simulation. The new phase consists of alternating linkages of the graphite layers via the formation of C-C sigma bonds. The calculated XAS and XRD reproduced most but not all of the features observed in a recent experiment. Comments are made on the reliability of the computational procedures to reproduce the XAS of these structures.
17.	Sjöberg, P, et al. (författare) AVERAGE LOCAL IONIZATION ENERGIES ON THE MOLECULAR-SURFACES OF AROMATIC SYSTEMS AS GUIDES TO CHEMICAL-REACTIVITY 1990 Ingår i: Canadian journal of chemistry (Print). - : Canadian Science Publishing. - 0008-4042 .- 1480-3291. ; 68:8, s. 1440-1443 Tidskriftsartikel (refereegranskat)abstract The average ionization energy, [Formula: see text], is introduced and is demonstrated to be useful as a guide to chemical reactivity in aromatic systems. [Formula: see text] is rigorously defined within the framework of self-consistent-field molecular orbital (SCF-MO) theory and can be interpreted as the average energy needed to ionize an electron at any point in the space of a molecule. An abinitio SCF-MO approach has been used to calculate [Formula: see text] at the 6-31G* level, using STO-3G optimized geometries. [Formula: see text] has been computed on molecular surfaces defined by the contour of constant electronic density equal to 0.002 electrons/bohr3, for a series of aromatic systems. This surface [Formula: see text] provides site specific predictions for preferred positions of electrophilic aromatic substitution. Relative reactivity toward electrophiles increases as the magnitudes of the smallest [Formula: see text] values [Formula: see text] for these systems decrease. An excellent relationship, with a correlation coefficient of 0.99, has been found between the Hammett constants and [Formula: see text]; this allowed us to predict the values of these constants for the substituents NHF and NF2, for which they were previously not known. Keywords: average local ionizations energy, chemical reactivity, electrophilic aromatic substitution, molecular surfaces, Hammett constants.
18.	Stevens, James R., et al. (författare) A comparison of acetone and poly(propylene glycol) as solvents for lithium triflate and lithium perchlorate 1991 Ingår i: Canadian journal of chemistry (Print). - : Canadian Science Publishing. - 0008-4042 .- 1480-3291. ; 69:12, s. 1980-1984 Tidskriftsartikel (refereegranskat)abstract Solutions of LiCF3SO3 and LiClO4 in acetone and in poly(propylene glycol) (PPG 400 and PPG 4000) have been compared by studying the nondegenerate, symmetric stretch (A1,SO3) and (A1,ClO4) Raman modes. The Raman spectra contain bands due to the symmetric stretching motion of the "free" anion and due to the symmetric stretching motion of anions in ion aggregates. It is concluded that "free" ions, ion pairs, triplets, and aggregates are present. Although PPG has a much lower dielectric constant, it is a better solvent for these salts than the dipolar aprotic acetone. These findings have ramifications on the current controversy of whether "free" ions are present at all in polyether–salt complexes such as PPG 4000/LiCF3SO3.
19.	Wennerberg, Anders B.A., et al. (författare) The structure of the rodent and porcine neuropeptide galanin and antagonists as determined by FTIR and CD spectroscopy 1994 Ingår i: Canadian journal of chemistry (Print). - : Canadian Science Publishing. - 0008-4042 .- 1480-3291. ; 72:6, s. 1495-1499 Tidskriftsartikel (refereegranskat)abstract FT-IR spectroscopy was used to study the conformation of the porcine neuropeptide galanin, fragments 1−16 of the porcine and human peptides and the antagonists M15 and M35. All peptides were shown to be structureless in aqueous solution. Upon addition to SDS micelles, only porcine galanin and the fragment consisting of amino acids 1−16 showed any evidence of interaction, adopting a helical structure. No interaction could be demonstrated with zwitterionic lipids for any peptide except M15 which formed a thermally unstable helical conformation which unfolded promoting aggregation at around 45 °C.Additional studies on rat galanin in various solvent systems were made by using circular dichroism spectroscopy. The results obtained support the observations made by FT-IR spectroscopy.
20.	Zhao, Qingrui, et al. (författare) One-step synthesis of Sb2O3 broom-like belts with controllable morphology 2005 Ingår i: Canadian journal of chemistry (Print). - 0008-4042 .- 1480-3291. ; 83:8, s. 1093-1097 Tidskriftsartikel (refereegranskat)abstract A direct and simple surfactant- and template-free route has been developed for the controlled synthesis of Sb2O3 belt-like microstructures. By adjusting the reactant ratio between SbCl3 and urea under solvothermal reaction conditions, broom-like belts and rods of Sb2O3 have been successfully prepared. X-ray powder diffraction (XRD), scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HR-TEM), and X-ray photoelectron spectroscopy (XPS) has been used to characterize the phases and morphologies of the as-prepared products. A possible formation mechanism is also discussed.Key words: antimony trioxide, solvothermal synthesis, broom-like belts.
21.	Zhou, Chuanzheng, et al. (författare) High-quality oligo-RNA synthesis using the new 2′-O-TEM protecting group by selectively quenching the addition of p-tolyl vinyl sulphone to exocyclic amino functions 2007 Ingår i: Canadian journal of chemistry (Print). - 0008-4042 .- 1480-3291. ; 85:4, s. 293-301 Tidskriftsartikel (refereegranskat)abstract During the F--promoted deprotection of the oligo-RNA, synthesized using our 2′-O-(4-tolylsulfonyl)ethoxymethyl (2′-O-TEM) group [Org. Biomol. Chem. 5, 333 (2007)], p-tolyl vinyl sulphone (TVS) is formed as a by-product. The TVS formed has been shown to react with the exocyclic amino functions of adenosine (A), guanosine (G), and cytidine (C) of the fully deprotected oligo-RNA to give undesirable adducts, which are then purified by HPLC and unambiguously characterized by 1H, 13C Heteronuclear Multiple Bond Correlation (HMBC) NMR and mass spectroscopic analysis. The relative nucleophilic reactivities of the nucleobases toward TVS have been found to be the following: N6-A > N4-C > N2-G > > N3-U. This reactivity of TVS toward RNA nucleobases to give various Michael adducts could, however, be suppressed by using various amines as scavengers. Among all these amines, morpholine and piperidine are the most efficient scavenger for TVS, which gave highly pure oligo-RNA even in the crude form and can be used directly in RNA chemical biology studies.

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