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991.
992.
993.
Angélica M. Lazarin 《Analytica chimica acta》2004,523(1):89-95
Methylene blue (MB) was strongly retained inside the cavity of host layered barium phosphate, without leaching, and the intercalated compound was characterized through X-ray power diffraction (XRD), IR spectra and electrochemical measurements. The intercalated dye compound was incorporated into a carbon paste electrode and, by means of cyclic voltammetry and amperometry, its electrochemical properties were investigated. In various electrolyte solutions, changing the pH between 3 and 9, the midpoint potential remained practically constant at −0.15 V. This is not the usual behavior for MB, since it is known that in the solution phase the midpoint potential changes considerably with pH. These data suggest that methylene blue behaves as a guest molecule in the lamellar structure of the barium phosphate. The electrode formed by this host/guest composition was used to investigate NADH electrochemical oxidation. 相似文献
994.
It is the first report on the atom transfer radical ring-opening copolymerizations of unsaturated cyclic acetal: 4,7-dimethyl-2-methylene-1,3-dioxepane (DMMDO) with conventional vinyl monomers, styrene (St), acrylonitrile (AN) and methyl acrylate (MA) in the presence of ethyl α-bromobutyrate as initiator and CuBr/2,2′-bipyridyl as catalyst/ligand at 110 °C. 1H, 13C NMR and IR data show that the copolymerizations of DMMDO with St (or AN or MA) yield the copolymers, poly(DMMDO-co-St) [or poly(DMMDO-co-AN) or poly(DMMDO-co-MA)] with narrow molecular weight distribution, and low content of DMMDO in the copolymers for electron-donor St, higher contents of DMMDO for electron-acceptor AN or MA are observed. 相似文献
995.
Yasutomo Yamamoto 《Tetrahedron》2005,61(2):379-384
Dimethylzinc-initiated radical reaction of THF with arylamines afforded aminoalcohols which were derived from the two molecules of THF and one molecule of an arylamine. The reaction seems to proceed via two-consecutive processes, electrophilic and then nucleophilic reactions of THF-derived species. Alkoxyamines and dialkylhydrazines reacted with electrophilic cyclic ether species to give the corresponding oximes and hydrazones of ω-hydroxyalkanal. 相似文献
996.
Poly(benzyl ether) dendrimers containing strongly fluorescent distyrylbenzene cores were synthesized, and their fluorescence and electrochemical properties as well as the action as fluorophores in the chemiluminescence reactions were investigated. While all the dendrimers exhibited almost the same properties except for their intensities, a characteristic feature due to the dendritic structure was observed in the electrochemical behaviors. In the peroxyoxalate chemiluminescence reactions using these dendrimers as fluorophores, a bimolecular interaction between the high-energy intermediates and fluorophores was established, and a decrease in the chemiluminescence intensity with an increasing generation was observed, which was connected with the insulating effect of the dendritic structures on the core. 相似文献
997.
Inhibitory effect of H_(3 + x)PMo_(12-x)V_xO_(40)-Ton the self-polymerization of methyl methacrylate
Yan-Bing Yin Hui-Song Wang Yu-Lin Yang Rui-Qing Fan Guo-Hua Dong Li-Guo Wei 《中国化学快报》2016,27(4):613-618
In this work,a series of molybdovanadophosphoric heteropoly acid quaternary ammonium salts H_(3+x)PMo_(12 -x)V_xO40-T were synthesized and employed as a reaction inhibitor in the selfpolymerization of methyl methacrylate(MMA).The polymerization inhibition effect of H_(3+x)PMoPMo_(12 -x)V_xO40-T)with different number of vanadium atoms and reaction dosages was investigated using differential scanning calorimetry(DSC).It shows that the inhibitory effect was improved with the increasing dosages of H_(3+x)PMoPMo_(12 -x)V_xO40-T),and the polymerization inhibition was also affected by the number of vanadium atoms in the H_(3+x)PMo_(12 -x)V_xO40-T .Furthermore,cyclic voltammograms(CV)was used to probe the mechanism of the inhibition reaction with H3+xPMo12xVxO40-T.The result of CV indicates that the inhibition reaction is an oxidation–reduction reaction.H_(3+x)PMo_(12 -x)V_xO40-T can react directly with the MMA monomer radicals,which eliminated the MMA monomers,and therefore the self-polymerization of the MMA can be effectively inhibited by H_(3+x)PMo_(12 -x)V_xO40-T. 相似文献
998.
John B. Paine III Yezdi B. Pithawalla John D. Naworal 《Journal of Analytical and Applied Pyrolysis》2008,82(1):42-69
The flash pyrolysis of d-glucose was investigated by the use of 13C labeling, in conjunction with GC/MS. Co-pyrolysis of uniformly labeled and unlabeled d-glucose established the extent of unimolecular formation of each of the pyrolysis products. A complete set of singly labeled d-glucose isotopologs was used to determine the origin of specific carbons within each of the pyrolysis products. The results were compared with the expected labeling patterns that arise when the cyclic Grob 1,3-diol fragmentation and the tandem alkaline pinacol rearrangement/retro-aldol fragmentation (TAPRRAF) discovered from the pyrolysis of glycerin are used to initiate breakage of the six-carbon chain of d-glucose. The most promising rationalizations provided by this exercise are presented herein, for the formation of six C3 and eight C4 acyclic carbonyl-containing pyrolysis products, and for 3-cyclopentene-1,2-dione. 相似文献
999.
In this paper, we study cyclic edge-cuts in fullerene graphs. First, we show that the cyclic edge-cuts of a fullerene graph
can be constructed from its trivial cyclic 5- and 6-edge-cuts using three basic operations. This result immediatelly implies
the fact that fullerene graphs are cyclically 5-edge-connected. Next, we characterize a class of nanotubes as the only fullerene
graphs with non-trivial cyclic 5-edge-cuts. A similar result is also given for cyclic 6-edge-cuts of fullerene graphs. 相似文献
1000.
Viswanathan Mahalingam Nataraj Chitrapriya Frank R. Fronczek Karuppannan Natarajan 《Polyhedron》2008,27(7):1917-1924
The synthesis and characterization of ruthenium(II) complexes, [RuCl2(dmso)2(bfmh)] (1; dmso = dimethyl sulfoxide, bfmh = benzoic acid furan-2-ylmethylene-hydrazide), [RuCl2(dmso)2(btmh)](2; btmh = benzoic acid thiophen-2-ylmethylene-hydrazide), [RuCl2(dmso)2(bfeh)](3; bfeh = benzoic acid (1-furan-2-yl-ethylidene)-hydrazide) and [RuCl2(dmso)2(bpeh)](4; bpeh = benzoic acid (1-pyridin-2-yl-ethylidene)-hydrazide) are described. The ligands, when treated with either cis-[RuCl2(dmso)4] or trans(Cl)–[RuCl2(dmso)2(bpy)], resulted in the same products. This has been confirmed by IR spectra and single crystal X-ray diffraction studies. The redox behaviors of the complexes have been found to be strongly dependent on the electronic nature of the moieties present in the hydrazone ligands. The binding of the complexes to Herring sperm DNA has been studied by absorption titration and cyclic voltammetry. But, due to the random change in the absorption on the addition of DNA, only a qualitative result rather than a quantitative result has been obtained. All the complexes have been found to bind DNA through different modes to different extents. The antibacterial properties of the ligands and the complexes have been studied against five pathogenic bacteria and also the minimum inhibitory concentrations (MIC) of all the ligands and complexes 2 and 4 have been evaluated. 相似文献