摘要:

AbstractMössbauer spectra of KSnBr3·2H2O were very broad and could not fit Lorentz equation, suggesting unresolvable quadrupole doublets. Its quadrupole splitting was estimated to be about 0.25mm/sfrom the separate experiments on frozen aqueous solutions of Sn(II)‐Br−systems. Stability constants of bromostannate(II) complexes were determined at μ = 3.5 from the Δ‐cLcurve by the approximation method, which were in agreement with the literatu

ISSN:0009-4536    

DOI:10.1002/jccs.198400029

出版商:WILEY‐VCH Verlag    

年代:1984

数据来源: WILEY

摘要:

AbstractMössbauer parameters of frozen salt solutions could be correlated with apparent degree of dissociation, γ. KSnCl3and KSnBr3were dissolved in 0.5MH2SO4, whereas NH4SnCl3was dissolved in 0.5MHClO4. Mössbauer studies were made at different concentratio

ISSN:0009-4536    

DOI:10.1002/jccs.198400030

出版商:WILEY‐VCH Verlag    

年代:1984

数据来源: WILEY

摘要:

AbstractConcentration dependence of isomer shift of K2SnCl6and tin(IV) chloride was studied. Tin was hydrolyzed in both cation and anion exchange resins after water washing. Two pairs of these two solutions showing the same isomer shift values, and therefore the same , were selected for further studies in HCl solutions and in anion exchange resins. The first pair was 0.04MK2SnCl6and tin(IV) chloride solutions (δ=0.00mm/s; =0): Their δ‐[HCl] curves coincided each other. Tin was sorbed on anion exchange resin as pentachlorstannate(IV) at (HCl)≤6N, and chiefly as hexachlorostannate(IV) at [HCl]≥7N.The both complexes were sorbed when 6N<[HCl]<9N. The δ‐[HCl] curves of the second pair, 0.4MK2SnCl6and 3Mtin(IV) chloride(δ =0.23mm/s;=3), also coincided each other, and tin was sorbed as pentachlorostannate(IV) from K2SnCl6solutions in the HCl concentration range st

ISSN:0009-4536    

DOI:10.1002/jccs.198400031

出版商:WILEY‐VCH Verlag    

年代:1984

数据来源: WILEY

摘要:

AbstractA procedure is describe for the adsorption of ion‐associated complex of iron(II) 3‐(2‐pyridyl)‐5, 6‐diphenyl‐1, 2, 4‐triazine (abbreviated as PDT) cation with tetra phenylborate (TPB) anion on macrocrystalline naphthalene. A water‐insoluble ion‐associated complex formed with PDT and TPB is quantitatively adsorbed on micro‐crystalline naphthalene. The solid mixture containing the colored complex is dissolved in acetonitrile and the absorbance was measured at 553nm.The other factors such aspH, amounts of reagents and naphthalene, shaking and standing times, diverse ions are studied. The method has been applied for the determination of iron in alloy

ISSN:0009-4536    

DOI:10.1002/jccs.198400032

出版商:WILEY‐VCH Verlag    

年代:1984

数据来源: WILEY

摘要:

AbstractThe Polarographic behaviour of quinaldic acid in the presence of lanthanide cations (Kd3+, Gd3+, Er3+) is studied atpH=4.5 and 0.1MHClO4as supporting electrolyte. The polarographic reduction gives two waves at lower concentrations of quinaldic acid and three waves at higher concentrations. The nature of the waves was investigated. The dissociation constant of quinaldic acid as well as the stability constants of some lanthanide cation complexes with quinaldic acid were determined potentiometrically in 75% (v/v) dioxane‐water at 25°Cand 0.1MKNO3. The solid complexes of Nd, Gd and Er were isolated and studied byir, differential thermal analysis (DTA) and thermogravimetric analysis (TGA) techniqu

ISSN:0009-4536    

DOI:10.1002/jccs.198400033

出版商:WILEY‐VCH Verlag    

年代:1984

数据来源: WILEY

摘要:

AbstractThe complexes ofN‐(2‐hydroxy‐1‐naphthalidene)anthranilic acid abbreviated (H2NA) with some trivalent rare earth elements (Pr, Nd, Sm, Gd, Dy, Er and Yb) were prepared. The complexes were characterized by chemical and thermal analysis,irand conductimetric methods. Two types of ionic complexes; Ln(HNA)2OH·2H2O with Dy, Er and Yb, and Ln(HNA)2OH with Pr, Nd, Sm and Gd were isolated. Coordination of the ligand with metal‐ions occurs through the carboxy group and the nitrogen atom. The acid dissociationconstants K1and K2of H2NA and the overall stability constants β1and β2of some lanthanide complexes in 75% (v/v) dioxan‐water solutions were determined by the potenti

ISSN:0009-4536    

DOI:10.1002/jccs.198400034

出版商:WILEY‐VCH Verlag    

年代:1984

数据来源: WILEY

摘要:

AbstractThe dual emission spectra of β‐naphthil in two different glasses at 77°Khave been resolved to their individual components by a computerized kinetic phosphorescence spectrometry system. Both the time‐resolved spectrum which reveals the kinetic behavior of the excited states and the wavelength‐resolved spectrum which tells the nature of the emitting species are obtained. Several possible emission mechanisms are discussed based on the informations gathered through the resolution processes. Triplet‐triplet annihilation is shown to exist in solutions of benzophenone as well as in solutions of β‐naphthil. As concluded from the results of time‐resolved study, such kind of interaction is responsible for the non‐exponential distorsion of the decays. And according to the wavelength‐resolved studies,transoidandcisoidconformational isomers seem to accout for the sources of the dual emis

ISSN:0009-4536    

DOI:10.1002/jccs.198400035

出版商:WILEY‐VCH Verlag    

年代:1984

数据来源: WILEY

摘要:

AbstractThe cycloadditions of the titled two maskedo‐benzoquinones,2and3, with monosubstituted ethylenes including ethyl acrylate, styrene, ethyl vinyl ether and 1‐hexene were studied. The reactions proceeded with high stereoselectivity and regioselectivity to giveendohead‐to‐head adducts when ethyl acrylate, styrene and ethyl vinyl ether were used as addenda. In the case of 1‐hexene, the reaction with2took place with high regioselectivity but low stereoselectivity to affordendoas well asexohead‐to‐head adducts while the reaction with3occurred with less regioselectivity to produce presumably all the eight possible isomers. The regiochemistry of the adducts were determined by the1Hnmranalysis of their hydrolysis products, bicyclo[2,2,2]oct‐5‐en‐2,3‐diones6, and the subsequent photolysis products, 1,3‐cyclohexadienes7. The stereochemistry was established by the study of the lanthanide induced shifts of compounds6a‐6fwith Fu(fod)3. The regioselectivity and stereoselectivity of these cycloaddition reactions were explained in terms of frontier molecular orbital theory and steric effect. The present study provides also a facile method to prepare regioselectively bicyclo[2, 2, 2]oct‐5‐en‐2,3‐diones (stereo‐selectively also) and 1,3‐cyclohexadienes from unsymmetri

ISSN:0009-4536    

DOI:10.1002/jccs.198400036

出版商:WILEY‐VCH Verlag    

年代:1984

数据来源: WILEY

摘要:

Abstract5‐Methoxy‐ and 5‐dimethylamino‐1‐methyl‐3‐oxidopyridiniums were shown to give the 1,3‐dipolar cycloadducts widely with methyl acrylate, acrylonitrile, N‐phenylmaleimide, styrene, phenylacetylene, cyclopentadiene, cyclopentene, diethyl azodicarboxylate a

ISSN:0009-4536    

DOI:10.1002/jccs.198400037

出版商:WILEY‐VCH Verlag    

年代:1984

数据来源: WILEY

摘要:

AbstractN‐Substituted 1,6‐dihydro‐3(2H)‐pyridinones have been synthesised from N‐substituted piperidine‐3,5‐diones via the methyl enol ethers. Reduction of the latter with sodium borohydride (NaBH4)

ISSN:0009-4536    

DOI:10.1002/jccs.198400038

出版商:WILEY‐VCH Verlag    

年代:1984

数据来源: WILEY