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101.
Pentafluorophenyliodine(III) Compounds. 2. Fluorine-Aryl Substitution Reactions on Iodinetrifluoride: Synthesis of Pentafluorophenyliodinedifluoride C6F5IF2 and Bis(pentafluorophenyl)iodonium Pentafluorophenylfluoroborates[(C6F5)2I]+[(C6F5)nBF4?n]? Mono- and disubstitution can be achieved in the fluorine-aryl substitution reaction on the low-temperature phase IF3 in CH2Cl2 at ?78°C depending on the aryl transfer reagent. With B(C6F5)3 [(C6F5)2I]+ [(C6F5)nBF4?n]? (68% yield) and with Cd(C6F5)2 C6F5IF2 (97% yield) is obtained whereas with C6F5SiMe3 no fluorine-aryl substitution takes place on IF3 even under basic conditions (EtCN or F? addition). At ?78°C in EtCN solution IF3 does not disproportionate but attacks the solvent under formation of HF. 相似文献
102.
Xe(OTeF5)2 reacts with Sb(OTeF5)3 under the formation of [Xe2(OTeF5)3]+[Sb(OTeF5)6]-. From SO2ClF solution a yellow solvate [F5TeOXe]+·SO2ClF· [Sb(OTeF5)6]- is formed with the crystal data: a = 1028.1(1), b = 1040.9(1), c = 1780.2(3) pm, α = 98.07(1), β = 97.68(1), γ = 105.82(1)°, space group . The O-Xe···O fragment is essentially linear (176.1(2)°), and the two Xe-O distances are quite different 197.1(4) and 242.6(4) pm. 相似文献
103.
Summary The elution behavior of alkali and earth alkaline cations has been studied on a newly synthesized weak cationexchanger (WCX). Applying this stationary phase isocratic separation of these cations is possible. The dependence of retention on competing ion concentration is described via a simple model. The influence of crown ethers as well as organic eluent additives on selectivity and peak efficiency is demonstrated. With optimized separation such cations can be determined with detection limits of about 0.5 ppm using a conductivity detector without ion suppression. 相似文献
104.
用混合床离子色谱柱同时测定阴阳离子 总被引:3,自引:0,他引:3
将阴离子交换树脂和阳离子交换换树脂混合后填充在一根色谱柱中,即所谓阴阳离子混合床柱。研究了阴阳离子在此混合柱上的保留行为并探讨了其保留机理。 相似文献
105.
Young Gun Ko Ung Su Choi Yong Sung Park Je Wan Woo 《Journal of polymer science. Part A, Polymer chemistry》2004,42(8):2010-2018
The role of hydrogen bonding in the chemistry of transition‐metal complexes remains a topic of intense scientific and technological interest. Poly(acrylo‐amidino diethylenediamine) was synthesized to study the effects of hydrogen bonding on complexes at different pHs. The polymer was synthesized through the coupling of diethylene triamine with polyacrylonitrile fiber in the presence of AlCl3 · 6H2O addition. The adsorption capacity of this polymer was 11.4 mequiv/g. The ions used for the adsorption test were CrO, PO, Cu2+, Ni2+, Fe2+, and Ag+. All experiments were confirmed with Fourier transform infrared. In the study of anion adsorption, at low pHs, only ionic bonds existed, whereas at high pHs, no bonds existed. However, in the middle pH region, both ionic bonds and hydrogen bonds formed between poly(acrylo‐amidino diethylenediamine) and the chromate ion or phosphate ion. When poly(acrylo‐amidino diethylenediamine) and metal ions (Cu2+, Ni2+, Fe2+, and Ag+) formed complexes, a hydrogen‐bonding effect was not observed with Fourier transform infrared. The quantity of metal ions adsorbed onto poly(acrylo‐amidino diethylenediamine) followed the order Ag+ > Cu2+ > Fe2+ > Ni2+. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 2010–2018, 2004 相似文献
106.
Reaction of Telluriumhexafluoride and Trimethylamine, Structures of the TeF5? and SeF5? Anions The reaction of TeF6 and (CH3)3N is of the redox kind, resulting in reduction of tellurium: X-ray single crystal analysis reveals the compounds (CH3)2N? CH2? N(CH3)2+TeF5? and [(CH3)3NH+]5(TeF5?)3(HF2?)2. By comparison with published data it can be shown that this mixture is identical to previously published [(CH3)3N]2TeF6. The latter was supposed to be one of the few examples of tellurium in a coordination state of eight. (CH3)4N+TeF5? and (CH3)4N4SeF5? are obtained and their structure is investigated by single crystal x-ray methods also. The anions SF5?, SeF5? and TeF5? are discussed in terms of weak interactions. 相似文献
107.
Shin-ichi NayaHisashi Miyama Kenji YasuTohru Takayasu Makoto Nitta 《Tetrahedron》2003,59(10):1811-1821
Three-step reactions starting from 2-chlorotropone with barbituric acid afforded novel 7,9-dimethylcyclohepta[b]pyrimido[5,4-d]furan-8(7H),10(9H)-dionylium tetrafluoroborate (9·BF4−), which is the isoelectronic compound of the 5-ethyl-3-methyllumiflavinium ion. The stability of cation 9 is expressed by the pKR+ value, which was determined spectrophotometrically, as ca. 6.0. The electrochemical reduction of 9 exhibited low reduction potential at −0.58 (V vs Ag/AgNO3), upon cyclic voltammetry (CV). In a search for the reactivity, reactions of 9·BF4− with some nucleophiles, hydroxide, hydride, amines, thiols, and methanol, were carried out to exhibit that the introduction of nucleophiles is dependent on the nucleophile itself. The photo-induced oxidation reactions of some alcohols catalyzed by 9·BF4− under aerobic conditions were carried out to give the corresponding carbonyl compounds in more than 100% yield [based on compound 9·BF4−], suggesting the oxidizing function of 9·BF4− toward alcohols in the autorecycling process. The UV-vis and fluorescence spectra of 9 were studied to suggest the electron transfer from alcohols to the excited 9. 相似文献
108.
发现以酒石酸和吡啶二甲酸等羧酸水溶液作淋洗剂时,钠,铵,钾,镁和钙等碱金属及碱土金属离子在ODS反相高效液相色谱柱上有明显的保留,而且相互之间能达到一定程度的分离。单独用分配或疏水作用等反相高效液相色谱的保留机理难以解释其保留行为。为此,作者提出了动态包固定相机理,即认为羧酸根阴离子因其疏水性在ODS固定相有保留,在固定相表面形成具有羧酸基阳离子交换树脂功能的动态包覆固定相。 相似文献
109.
New Alkali Oxoarsenates(V): NaLi2[AsO4] — A New Type of Formula [1] . By heating of well ground mixtures of the binary oxides As2O3, Na2O, and Li2O2, molar ratio As:Na:Li = 1.0:1.0:2.0, in a well closed Ni tube (650°C, 21 d) colourless single crystals of NaLi2[AsO4] were obtained for the first time. The new orthoarsenate(V) crystallizes orthorhombic (space group P mn21-C, No. 31) with Z = 2. The structure determination showed that it is isostructural to βII-Li3[VO4] and that means the Li3[PO4]-type. The lattice constants a = 702.9(2) pm, b = 520.5(1) pm, c = 505.4(2) pm were taken from Guinier-Simon powder data. The structure was determined by four-circle diffractometer data [Philips PW 1 100, AgKα , 679 independent out of 2 373 Io(hkl), R = 3.03%, Rw = 2.29%; parameter see text]. The Madelung Part of Lattice Energy, MAPLE, and Effective Coordination Numbers, ECoN, these calculated via Mean Fictive Ionic Radii, MEFIR, are calculated and discussed. 相似文献
110.