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191.
Xiao‐Feng Wang Yang Lv Zhi Su Taka‐aki Okamura Gang Wu Wei‐Yin Sun Prof. Dr. Norikazu Ueyama 《无机化学与普通化学杂志》2007,633(15):2695-2700
The metal complexes [Hg2(tbim)2Br4]·2DMF ( 1 ) and [Hg2(tbim)I4]·1.5DMF ( 2 ) were prepared by reactions of 1,3,5‐tris(benzimidazol‐1‐ylmethyl)‐2,4,6‐trimethylbenzene (tbim) with HgBr2, HgI2, respectively, and [Hg2(tbim)I4]·0.5(FeCp2)·H2O ( 3 ) was obtained by the same method with addition of ferrocene (FeCp2) as additive. Their structures were determined by X‐ray crystallographic analyses. Complex 1 has a macrocyclic binuclear structure with one benzimidazole arm of the ligand free of coordination and the binuclear units are further connected by C‐H···N hydrogen bonds to give an infinite zigzag chain. Complexes 2 and 3 have a 2D network structure in which tbim serves as a tridentate ligand. The results showed that the halides of bromide and iodide have remarkable impact on the structure of the complexes. The FeCp2 molecules are trapped in the voids of framework 3 . 相似文献
192.
Ketene silylacetals derived from prenyl and (Z)- and (E)-crotyl 2-methylcyclopentanecarboxylates (9) were subjected to the Ireland-Claisen rearrangement. All three substrates rearranged with complete facial selectivity, but the (Z)- and (E)-crotyl systems gave a mixture comprised of the same diastereomers of 1-(1-methyl-2-propenyl)-2-methylcyclopentanecarboxylic acid (14) in ratios of 2:1 and 1:2, respectively. In contrast, the ketene silylacetals prepared from allyl and prenyl 2-methoxycyclopentanecarboxylates (22) underwent rearrangements with both facial stereochemistries. 相似文献
193.
CoCl_2·6H_2O or LaCl_3·7H_2O Catalyzed Biginelli Reaction. One-Pot Synthesis of 3,4-Dihydropyrimidin-2(1 H)-ones 总被引:1,自引:0,他引:1
Introduction1,4 Dihydropyridinesofthenifedipinetype (e .g .I—III)arethemoststudiedclassoforganiccalciumchannelmedicine ,whichhavebecomealmostindispens ableforthetreatmentofcardiovasculardiseasessuchashypertension ,cardiacarrhythmias ,orangina .1Inthepastdecade… 相似文献
194.
Xi Bao Gao Jiang Yu Ning Li Hong Yin Yin Jing He Yang 《中国化学快报》2007,18(10):1289-1292
A new structured metallic nanomaterial of europium nanoparticle was prepared using tannic acid as the reductive agent,and nanoeuropium protein conjugates were synthesized by the method of lipoic acid modification on the surface of nanoparticle,which opens a new field of application of lanthanides in nanotechniques.Their properties were also characterized by UV-vis absorption spectroscopy,transmission electron microscopy (TEM),and fluorescence spectroscopy.The europium nanoparticle and its protein conjugates solution were stable and water-soluble.The fluorescence intensity of the composite europium nanoparticles was significantly increased in the presence of trace protein,and was linear proportional to the concentration of proteins under optimum conditions.According to this,a fluorimetric method for the determination of protein was developed in this paper. 相似文献
195.
A new compound (5R, 10R)-3,8-dihydroxy-5,10-diethoxy-5,10-dihydrochromeno[5,4,3-cde]chromene monohydrate was obtained from 3,4-dihydroxybenzaldehyde in aerobic basic aqueous ethanol solution in the presence
of manganese chloride and triethylamine and crystallized in orthorhombic P212121 space group (denoted as 1). When 1 was recrystallized from aqueous methanol, it was transformed to another crystal (2) with the same composition but in P21/n space group. The drastic difference in the extensive hydrogen bond network makes 1 a 3D and 2 a 2D infinite supramolecular structure, respectively. 相似文献
196.
Masterson DS Yin H Chacon A Hachey DL Norris JL Porter NA 《Journal of the American Chemical Society》2004,126(3):720-721
Strategies are reported that combine in one step a predictable chemical-based protein digestion with mass spectrometry. Lysine residue amino groups in peptides and proteins are modified by reaction with a peroxycarbonate derived from p-nitrophenol, and tert-butyl hydroperoxide. The peroxycarbonate reacts with lysine residues in peptides and proteins, and the resulting lysine peroxycarbamates undergo homolytic fragmentation under conditions of low-energy collision-induced dissociation (CID). Observed fragmentation of the peptides involves apparent free radical processes including Hofmann-L?ffler-type rearrangements that lead to peptide chain fragmentation. Strategies for directed cleavage of peptides by free radical promoted processes are feasible, and such strategies may well simplify schemes for protein analysis. 相似文献
197.
Speciation of arsenic in environmental samples gains increasingly importance, as the toxic effects of arsenic are related to its oxidation state. A method was developed for the determination of trace amounts of arsenic (III) and total arsenic by flow injection hydride generation coupled with an in-house made non-dispersive AAS device. The total arsenic is determined after prereduction of arsenic (V) to arsenic (III) with L-cysteine in a low concentration of hydrochloric, acetic or nitric acid. The conditions for the prereduction, hydride generation and atomization were systematically investigated. A quartz tube temperature of 800 degrees C was found to be optimum in view of peak shape and baseline stability. Pb(II), Ni(II), Fe(III), Cu(II), Ag(I), Al(III), Ga(II), Se(IV), Bi(III) were checked for interfering with the 2 microg/L As(V) signal. A serious signal depression was only observed for Se(IV) and Bi(III) at a 150-fold excess. With the above system, arsenic was determined at a sampling frequency of about 1/min with a detection limit (3sigma) of 0.01 microg/L using a 0.5 mL sample. The reagent blank was 0.001+/-0.0003 absorbance units and the standard deviation of 10 measurements of the 2 microg/l As signal was found to be 1.2%. Results obtained for standard reference materials and water samples are in good agreement with the certified values and those obtained by ICP-MS 相似文献
198.
199.
The anion of 2-aryl acetonitrile derivatives reacted with a variety of heteroaryl chlorides or bromides in an S(N)Ar manifold to afford intermediate anions which were susceptible to oxidation. The addition of sodium peroxide and aqueous NH(4)OAc solution effected oxidation to afford aryl heteroaryl ketones in good yields. Aryl acetonitrile derivatives are thus umpolung-type synthons of the corresponding aryl carbonyl functionality. 相似文献
200.
三苄基锡二硫代氨基甲酸酯的合成 总被引:3,自引:1,他引:3
三苄基锡二硫代氨基甲酸酯的合成尹汉东马春林*张如芬(聊城师范学院化学系聊城252059)关键词三苄基氯化锡,二硫代氨基甲酸盐,合成1997-07-10收稿,1997-09-09修回山东省自然科学基金资助项目三烃基锡衍生物是一类具有较强生物活性的有机锡... 相似文献