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41.
Mohammad R.?SaidiEmail author Mohammad?Nazari 《Monatshefte für Chemie / Chemical Monthly》2004,135(3):309-312
Summary. The solid LiClO4-mediated one-pot reaction of aldehydes with secondary amines and C nucleophiles afforded the corresponding aminoalkylation products in high yields. Unlike the previous reported procedure, the aminoalkylation of aldehyde was achieved in the presence of only 0.5 equivalents of solid lithium perchlorate in dichloromethane as the solvent with good to high yields at room temperature. 相似文献
42.
Irradiation of the red-light absorbing dye, methylene blue (MB), in the presence of the metal complex, cis-Rh(phen)2Cl2+ (BISPHEN), leads to irreversible photobinding of both reagents to DNA. Evidence from absorption and emission spectroscopy indicates that the dye is strongly complexed to the DNA at the concentrations used in the experiments and that this complex is unaffected by the presence of BISPHEN. The level of covalent binding is proportional to the absorbed light dose, with the quantum efficiency for covalent binding of BISPHEN to the DNA with 633 nm light equal to 3.5 x 10(-4). Electrospray ionization mass spectrum of a mixture of DNA fragments created by enzymatic degradation of DNA isolated following irradiation indicates that purine adducts are formed with both BISPHEN and the dye. In addition, UV-Vis and high-performance liquid chromatography analyses of the irradiated MB/BISPHEN/DNA mixture and isolated adducts show extensive conversion of the dye and metal complex to the corresponding N-demethylated and aquated derivatives, respectively. Triplet quenchers for MB, for example oxygen and benzoquinone, inhibit both the photoconjugation and the photochemistry of BISPHEN. A mechanism for the synergistic interaction is proposed that involves photoconjugation of both partners to the DNA following oxidation and reduction via electron transfer between 1MB*/DNA and 3MB*/BISPHEN. 相似文献
43.
44.
Mohammad Ali Zolfigol Iraj Mohammadpoor-BaltorkDavood Habibi BiBi Fatemeh MirjaliliAbdolhamid Bamoniri 《Tetrahedron letters》2003,44(44):8165-8167
Primary and secondary trimethylsilyl ethers were converted to their corresponding ethers in the presence Nafion-H® with good to excellent yields under mild and heterogeneous conditions. 相似文献
45.
Liquid-liquid equilibrium data for mixtures of (ethylene carbonate + benzene + cyclohexane) at temperatures 303.15 and 313.15 K and (ethylene carbonate + BTX + cyclohexane) at temperature 313.15 K are reported, where the BTX is benzene, toluene and m-xylene. The compositions of liquid phases at equilibrium were determined by gas liquid chromatography. The selectivity factors and partition coefficients of ethylene carbonate for the extraction of benzene, toluene and m-xylene from (ethylene carbonate + BTX + cyclohexane) are calculated and presented. The obtained results are compared with the selectivity factors and partition coefficients of ethylene carbonate for the extraction of benzene from (ethylene carbonate + benzene + cyclohexane). The liquid-liquid equilibrium data were correlated with the UNIQUAC and NRTL activity coefficient models. The phase diagrams for the studied mixtures are presented and the correlated tie line results have been compared with the experimental data. The comparisons indicate the applicability of the UNIQUAC and NRTL activity coefficients model for liquid-liquid equilibrium calculations of the studied mixtures. The tie line data of the studied mixtures also were correlated using the Hand method. 相似文献
46.
Low molecular weight organogels based on long-chain carbamates 总被引:2,自引:0,他引:2
Moniruzzaman M Sundararajan PR 《Langmuir : the ACS journal of surfaces and colloids》2005,21(9):3802-3807
Thermoreversible organogels were prepared from carbamates with alkyl side chains of different lengths. Gelation was possible only up to an alkyl side chain length of 12 carbons, beyond which crystallization occurs, due to the dominant van der Waals interaction between the alkyl chains. This is in contrast to other alkane-based organogels, in which gelating efficiency increased with the length of the alkane chain (see Abdallah, D. J.; Weiss, R. G. Adv. Mater. 2000, 12, 1237). The critical concentration for gelation decreases drastically with an increase in the side chain length. Xerogels of these show birefringent fibers with uniform cross section and unlimited growth in one direction. The extent of this unlimited growth is affected by the length of the alkyl side chain in the carbamate, which finally ceases the gel formation ability of the carbamate. Cryogenic scanning electron microscopy images of the gels are similar to those of xerogels. From X-ray diffraction of the fibers, we propose that the growth direction is along the plane of hydrogen bonds between the carbamate molecules. The thickness of the fibers depends on the length of the alkyl side chain. Morphological differences are seen between gels prepared by slow cooling and quenching of the solution. Thus, the morphology of the fibrous xerogels of the carbamates can be tailored for specific applications, by the choice of the alkyl side chain length and the rate of cooling the solution. 相似文献
47.
Behzad Haghighi Mohammad Reza Hussaindokht Mohammad Reza Bozorgmehr Naser Seyed Matin 《中国化学快报》2007,18(9):1154-1158
In this paper five equations of state are tested for checking their ability to predict the Joule-Thomson inversion curve.These five equations of state are:Mohsennia-Modarres-Mansoori(MMM),Ji-Lemp(JL),modified Soave-Redlich-Kwang(SRK)equation of state by Graboski(MSRK1),modified SRK equation of state by Peneloux and Rauzy(MSRK2),and modified Peng-Robinson (PR)equation of state by Rauzy(PRmr).The investigated equations of state give good prediction of the low-temperature branch of the inversion curve,except for MMM equation of state.The high-temperature branch and the peak of the inversion curve have been observed,in general,to be sensitive to the applied equation of state.The values of the maximum inversion temperature and maximum inversion pressure are calculated for each component used in this work. 相似文献
48.
JPC – Journal of Planar Chromatography – Modern TLC - A water-in-oil microemulsion has been used for the first time as a mobile phase in thin-layer chromatography of amino acids. A new... 相似文献
49.
50.
Selected valence electron split-shell molecular orbital calculations have been performed on the diatomic interhalogen molecules in order to obtain their binding energies, equilibrium internuclear distances, vibrational force constants, dipole moments and nuclear quadrupole coupling constants. The results are compared with the corresponding closedshell values and with those of some previous semiempirical and nonempirical all valence electron calculations. It is observed that the selected valence electron split-shell molecular orbital method which involves the least amount of computations yields results in better agreement with experiment than other methods. 相似文献