摘要:

AbstractThe resonance Raman spectra of gaseous iodine bromide IBr have been studied with the excitation of various argon ion laser lines from 5017 to 4579Å. The fine structures of the fundamental and few overtones of IBr are also studied by various power of 4880Å laser line. The resonance Raman scattering is found to be strong as that of Br2and ICI. A new term “apparent spectroscopic temperature” is suggusted for the case of the resonance Raman scattering. The apparent spectroscopic temperatures measured in this cell show that the system is not in thermal equilibrium. Br2is the hottest and I2is the coldest. IBr is in the middle. Unfortunately, no chemical reaction enhanced phenomenon is found although there should be some chemical reactions occurring under the laser light. The initiating reaction is the photodissociation of the main component IBr which also has large absorptivity. Because of the non‐crossing between the B3Π and the1Π states, the primary products of the photodissociation should be I and Br. The chemical reactions of I and Br with IBr follow. The reactions of I and IBr is endothermic but the reaction of Br with IBr is exothermic. Therefore vibrational hot Br2is produced and its apparent spectroscopic temperature should be higher. On the other hand, the apparent spectroscopic temperature of I

ISSN:0009-4536    

DOI:10.1002/jccs.198600001

出版商:WILEY‐VCH Verlag    

年代:1986

数据来源: WILEY

摘要:

AbstractCrystal and molecular structures of the neutral ligand hydrate, C24H16N8·H2O, and the diamagnetic nickel(II) complex, [Ni(C C24H16N8)], have been determined by three‐dimensional X‐ray crystallography. Pertinent data are: C24H16N8·H2O, Pnmm withZ=2,a=4.6142(3),b=14.7687(7), c=15.0650(5) Å,R=0.068,Rw= 0.038; [Ni(C24H16N8), 12/cwithZ=4,a=22.0137(11),b=3.7637(4),c=23.4742(11) Å, β=92.7(1)°,R= 0.039,Rw=0.025. The overall conformations of the neutral ligand and the Ni(II) complex are similar, both have a pronounced saddle shape. The Ni(II) ‐N bond distances in the Ni‐complex are 1.861(2) and 1.998(2) Å. The distances from nitrogen atoms to the center of the ring in free ligand are 2.020(3) and 2.220(3)Å, which arc significantly longer than those of Ni(II) complex A detailed comparison about the core size with similar liga

ISSN:0009-4536    

DOI:10.1002/jccs.198600002

出版商:WILEY‐VCH Verlag    

年代:1986

数据来源: WILEY

摘要:

AbstractCrystal and molecular structures of the planar neutral ligand, C26H16N8, and the four isomorphous five‐coordinated metal complexes, [M(C26H16N8)(H2O)], M = Mn(II), Co(II), Cu(II), Zn(II), have been determined from three‐dimensional X‐ray diffraction data. The free ligandhpH2, C26H16N8, belongs to the P 21/cspace group withZ=2,a=4.142(3),b=23.736(6),c=10.338(3) Ä, β=94.66(6)°. The metal complexes monohydrate Mhp‐H2O all belong to the orthorhombic Pcab space group withZ=8. The dimensions are roughly 8.8×19.3×23.7 Å3. In each structure, the macrocyclic ligand has an almost planar conformation which differs from the saddle shaped ligand hydrate (hpH2·H2O) and the nickel complex [Nihp]5. The distances from the center of the macrocyclic ring to the nitrogen atom of the free ligand are 1.907(6) and 2.245(6)Å. The coordination geometry in these four complexes is square pyramidal with a water molecule as an axial ligand. The bond distances of M(II)‐O(H2O), M(II)‐N1 (imine), M(II)‐N3 (pyridine) are: 2.19(1), 2.00(2), 2.27(2)Å respectively for the manganese complex; 2.08(1), 1.97(1), 2.23(1)Å for the cobalt complex; 2.33(1), 1.92(3), 2.18(1)Å for the copper complex; 2.110(5), 1.964(6), 2.252(6)Å for the zinc complex. The variation of metal‐ligand distances can be correlated to the metaldorbital occupancy. A comparison with simila

ISSN:0009-4536    

DOI:10.1002/jccs.198600003

出版商:WILEY‐VCH Verlag    

年代:1986

数据来源: WILEY

摘要:

AbstractA method for the simultaneous determination of trace Dy, Eu, Gd and Sm in nuclear grade uranium oxide by Inductively Coupled Plasma Atomic Emission Spectrometry has been developed. The process of uranium extraction and ICP/AES optimization are investigated. The detection limits of Dy, Eu, Gd and Sm are 0.003, 0.002, 0.006 and 0.010 μg/mlrespectively, and more than 90% recovery can be obtained

ISSN:0009-4536    

DOI:10.1002/jccs.198600004

出版商:WILEY‐VCH Verlag    

年代:1986

数据来源: WILEY

摘要:

AbstractAcid dissociation constants of substituted‐5‐pyrazolone dyes have been determined potentiometrically in 75%(v/v)dioxane‐water mixture at 30°C and<0.1 ionic strength. The stability constants of their 1:1 and 1:2 chelates with tweleve trivalent lanthanide ions have been determined under the same conditions. The data were correlated and the results were taken to explain the stabilization of such. chelates by dative π ‐bonding between Ln (III) and t

ISSN:0009-4536    

DOI:10.1002/jccs.198600005

出版商:WILEY‐VCH Verlag    

年代:1986

数据来源: WILEY

摘要:

AbstractThymolphthalein (I) as an acid‐base indicator is successfully reduced in sodium hydroxide medium and zinc dust into a colorless reagent (Thymolphthalin (III)). The latter is used as an analytical reagentin thecolorimetric determination of some mildly strong oxidising agents such as potassium ferricyanide.Ferricyanide, ferrocyanide and a mixture of both are spectrophotometrically determined at 592 nm. Dichromate oxidises ferrocyanide to ferricyanide without interference on the reaction. The results obtained showed that the system does obey Beer's law over the concentration range 20–170ugferricyanide per 25ml.The molar absorbitivity is (4.28+0.02)×103cm2mg−1

ISSN:0009-4536    

DOI:10.1002/jccs.198600006

出版商:WILEY‐VCH Verlag    

年代:1986

数据来源: WILEY

摘要:

AbstractA model for the mechanism of the Gel permeation chromatographic separation of a polymer and a new calibration method have been developed, based on the exclusion of the polymer from the pores of the packing material. We propose that the calibration curve a plot of log (1—√K) versus log (molecular weight), whereKis the elution volume coefficient, is close to linear over aKrange of 0.15–0.85. We compare our procedure with that of Haller for various sets of data. Our procedure is generally better with lower standard deviations. When extrapolated, it gives a critical permeation size characteristic of the glass column pac

ISSN:0009-4536    

DOI:10.1002/jccs.198600007

出版商:WILEY‐VCH Verlag    

年代:1986

数据来源: WILEY

摘要:

Abstract3‐Aryl‐4‐(5‐aryl‐Δ2‐1,2,4‐oxadiazolin‐3‐yl)sydnones (5) were synthesized in high yields by the reaction of 3‐arylsydnone‐4‐carboxamide oximes (prepared from the corresponding 3‐arylsydnone‐4‐carbonitriles) with aromatic aldehydes in the presence of acid catalysts. No reaction occurred when aliphatic aldehydes were used. The oxadiazolin‐3‐ylsydnones (5) were easily converted into the corresponding 3‐aryl‐4‐(5‐aryl‐1,2,4‐oxadiazol‐3‐yl)sydnones byN‐bromosuccinimide oxidation. The 3‐arylsydnone‐4‐carbonitrile oxides were synthesized in good yields byN‐bromosuccinimide oxidatio

ISSN:0009-4536    

DOI:10.1002/jccs.198600008

出版商:WILEY‐VCH Verlag    

年代:1986

数据来源: WILEY

摘要:

AbstractCycloadditions of 3,5‐di‐t‐butyl‐o‐benzoquinone with diphenylacetylene, dimethyl acetylenedicarboxylaet, 3‐hexyne, phenylacetylene, methyl propiolate, 1‐octyne and 3‐hydroxy‐3‐methyl‐1‐butyne were studied. The reactions occur periselectively across the diene moiety of 3,5‐di‐t‐butyl‐o‐benzoquinone to give bicyclo[2.2.2]octa‐5,7‐diene‐2,3‐diones. In the cases of monosubstituted acetylenes, the reactions take place regioselectively. The selectivities are explained in terms of electronic and steric effects.The cycloadditions of two masked 3,5‐di‐t‐butyl‐o‐benzoquinones 7 and 8 with monosubstituted acetylenes, phenylacetylene, methyl propiolate, 1‐octyne and 3‐hydroxy‐3‐methyl‐1‐butyne were also examined. Compound 7 reacts with high regioselectivity to give only bicyclo[2.2.2]octa‐5,7‐diene‐2,3‐diones 10 upon subsequent hydrolysis; the high regioselectivity was explained as the result of coherent electronic and steric effects. Compound 8 reacts with monosubstituted acetylenes to give either 9 or 10 or both upon subsequent hydrolysis, depending on the nature of the substituents on acetylene. Thi

ISSN:0009-4536    

DOI:10.1002/jccs.198600009

出版商:WILEY‐VCH Verlag    

年代:1986

数据来源: WILEY

摘要:

AbstractIn the presence of pyridine, 3‐aryl‐4‐formylsydnone (II) reacts with hydroxyl‐amine hydrochloride to produce 3‐aryl‐4‐formylsydnone oxime (III). This reaction was performed in ethanol solution with reflux or at room temperature; the latter procedure gave an excellent yield (74‐98%) and high purity.(III) reacts in acetic anhydride at room temperature to give 3‐aryl‐4‐formylsydnone oxime O‐acetate (IV).A convenient method for the synthesis of 3‐aryl‐4‐cyanosydnone (V) is to dehydrate (III) with acetic anhydride at reflux. When (IV) was refluxed with acetic anhydride, (V) was similarly obtained. Another convenient method to prepare (V) from (III), dehydration with thionyl chloride at room tempe

ISSN:0009-4536    

DOI:10.1002/jccs.198600010

出版商:WILEY‐VCH Verlag    

年代:1986

数据来源: WILEY