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Zinc Bromide (zinc + bromide)
Selected AbstractsChemInform Abstract: Zinc Bromide as Catalyst for the Stereoselective Construction of Quaternary Carbon: Improved Synthesis of Diastereomerically Enriched Spirocyclic Diols.CHEMINFORM, Issue 13 2001Yong Qiang Tu Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] Polysulfone ionomers functionalized with benzoyl(difluoromethylenephosphonic acid) side chains for proton-conducting fuel-cell membranesJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 2 2007Benoît Lafitte Abstract Polysulfones carrying benzoyl(difluoromethylenephosphonic acid) side chains were prepared and investigated for use as proton-conducting fuel-cell membranes. In the first step, polysulfones were lithiated and reacted with methyl iodobenzoates to prepare p - and o -iodobenzoyl polysulfones. Next, the phosphonated polysulfones were prepared via CuBr-mediated cross-coupling reactions between the iodinated polymer and [(diethoxyphosphinyl)difluoromethyl]zinc bromide. Finally, dealkylation with bromotrimethylsilane afforded highly acidic CF2PO3H2 derivatives. The replacement of the iodine atoms by CF2PO3Et2 units was almost quantitative in the case of o -iodobenzoyl polysulfone. Membranes based on ionomers having 0.90 mmol of phosphonic acid units/g of dry polymer took up 6 wt % water when immersed at room temperature, and conductivities up to 5 mS cm,1 at 100 °C were recorded. This level of conductivity was comparable to that reached by a membrane based on a sulfonated polysulfone having 0.86 mmol of sulfonic acid/g of dry polymer. Thermogravimetry revealed that the arylCF2PO3H2 arrangement decomposed at approximately 230 °C via cleavage of the CP bond. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 269,283, 2007. [source] Halogeno(triazolyl)zinc complexes as molecular building blocks for metal,organic frameworksACTA CRYSTALLOGRAPHICA SECTION C, Issue 12 2009Jörg Lincke The isomorphous title complexes, dichlorido[4-(3,5-dimethyl-4H -1,2,4-triazol-4-yl)benzoic acid-,N1]zinc(II) dihydrate, [ZnCl2(C11H11N3O2)2]·2H2O, and dibromido[4-(3,5-dimethyl-4H -1,2,4-triazol-4-yl)benzoic acid-,N1]zinc(II) dihydrate, [ZnBr2(C11H11N3O2)2]·2H2O, were synthesized and crystallized by slow evaporation of the solvent from a solution of the ligand and either zinc chloride or zinc bromide, respectively, in water/ethanol. The ZnII ions occupy twofold axes in the noncentrosymmetric orthorhombic space group Fdd2. The metal ion is approximately tetrahedrally coordinated by two monodentate triazole groups of the ligands and additionally by two halide ions. The water molecules incorporate the complexes into a three-dimensional framework made up by hydrogen bonds. Furthermore, each complex possesses two hydrogen-bond-donor sites represented by the carboxy groups and two acceptor sites at the noncoordinating N atoms of the triazoles. [source] Allylation of aldiminomercaptotriazinones using allyl halides and allylmetal compoundsHETEROATOM CHEMISTRY, Issue 3 2003Ashraf A. El-Shehawy Allylation of 4-amino-3-mercapto-6-methyl-4H -1,2,4-triazin-5-one (1) and its arylideneamino derivatives 5 was performed through two different methods. Reaction of 1 and 5 with allylic bromides 2 in the presence of sodium ethoxide afforded a mixture of S - and N -allylated products. Treatment of arylimines 5 with allylic zinc bromides 9 and triallylborane reagents 12 did not affect the hetero-ring opening but the CN bond of the lateral chain underwent the addition reaction yielding the C -allylated products 10. © 2003 Wiley Periodicals, Inc. Heteroatom Chem 14:280,287, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.10144 [source] | ||||||||||