摘要:

AbstractThe surface pressure‐area diagrams of double‐chain fluorocarbon amphiphiles with different headgroup compositions show that the amphiphiles arrange almost perpendicularly to the water subphase and the structure of headgroups exerts significant influence on the amphiphile packing. Strong hydrogen bonding and weak electrostatic interaction favor the formation of stable monolayers. Perfluorooctanoic acid (FOA) cannot form monolayer at water/air interface and can only form liquid monolayer in subphase of calcium nitrate solution. Complete phase separation of palmitic acid and a fluorocarbon amphiphile with shorter hydrocarbon spacer group, 1, could be demonstrated in monolayers by using the phase rule of Crisp. The creation of phase‐separated monolayers is possible when the monolayer is composed of a mixture of palmitic acid and a fluorocarbon amphiphile with longer hydrocarbon spacer group, 2. It can be suggested that the miscibility of hydrocarbon amphiphiles with fluorocarbon amphiphiles is determined by the hydrocarbon fraction of fluorocarbon amphip

ISSN:1001-604X    

DOI:10.1002/cjoc.19920100601

出版商:Wiley‐VCH Verlag GmbH&Co. KGaA, Weinheim    

年代:1992

数据来源: WILEY

摘要:

AbstractThe crystal structure oftert‐butoxycarbonyl‐D,L‐isoleucyl‐glycyl methyl ester was determined by the X‐ray method. The space group isP21witha= 9.115(3),b= 12.075(4),c= 16.258(5) Å, β = 89.84(3) and Z = 4. It was observed that in the peptides which contain IleGly fragment the carbonyl group of Gly residue has less tendency to form hydrogen bond than that of Ile residue. This tendency was supported by the atomic net charges calculated with the quantum mechanics pro

ISSN:1001-604X    

DOI:10.1002/cjoc.19920100602

出版商:Wiley‐VCH Verlag GmbH&Co. KGaA, Weinheim    

年代:1992

数据来源: WILEY

摘要:

AbstractFourteen new mixed ligand complexes of lanthanide acetylacetonate and dibenzo‐18‐ crown‐6 (DB18C6) were prepared by three different methods. The composition of the complexes was shown to be Ln(acac)· DB18C6 by elemental analysis and X‐ray powder diffraction. Infrared spectra of the complexes were investigated, and the results indicate that their absorption bands in the region of 400—4000 cm−1are complicated and without much difference from each other, but in the far infrared region various absorption bands of Ln—O can be observed and they changes regularly with the atomic number

ISSN:1001-604X    

DOI:10.1002/cjoc.19920100603

出版商:Wiley‐VCH Verlag GmbH&Co. KGaA, Weinheim    

年代:1992

数据来源: WILEY

摘要:

Abstract[Mo3,OS3(dtp)4(H2O)] reacts with NaOAc·3H2O in Py to give the title compound. The crystal data are as follows: [Mo2OS3)(OAc)2(dtp)2·Py]−0.5H,O(dtp = [S3P(OC2H5)2]−, Py = C5H5N);M= 976.64; triclinic; space groupP1;a=11.704(5),b=14.169(7),c= 11.688 (5) Å α=109.94(4) β = 91.53(4),γ= 91.93(4)°;V= 1819(1) Å2;Z=2;Dc= 1.78 g·cm−3λ(Mo Kα) = 0.71069 Åμ=15.15 cm−1; F(000) = 970T=296 K; final R=0.071 for 1652 reflections withI>3σ(I). In the molecule, the [Mo3OS3] core is surrounded by two bridging OAc groups and two terminal chelate dtp groups attached to the {Mo3} triangle in a symmetric style, and the Py ligand is coordinated to the Mo atom at the apex of {Mo3} triangle with the nitrogen. This novel configuration is obtained for the first time with Mo—N bond length being 2.27 (2) Å and three Mo—Mo bond lengths 2.584 (4), 2.587 (4) and 2.657(4) Å, respectively. As a whole, the molec

ISSN:1001-604X    

DOI:10.1002/cjoc.19920100604

出版商:Wiley‐VCH Verlag GmbH&Co. KGaA, Weinheim    

年代:1992

数据来源: WILEY

摘要:

AbstractThe dissociation kinetics of metal ions from native metallothionein (Cd5Zn2‐MT) of rat liver has been studied in the presence of external ligands including amino acids, peptide and polyamino polycarboxylic acids at 25°C. The study shows that the solution pH affects the metal dissociation process. Different ligands present different multiphasic kinetics. The possible mechanism of metal dissociation from metallothionein has been propos

ISSN:1001-604X    

DOI:10.1002/cjoc.19920100605

出版商:Wiley‐VCH Verlag GmbH&Co. KGaA, Weinheim    

年代:1992

数据来源: WILEY

摘要:

AbstractA crystal complex with the formula [Na(B15C5)+]2[Hg3Cl8]2‐·H2O was synthesized by the reaction of benzo‐15‐crown‐5 with sodium chloride and mercuric chloride. Its crystal and molecular structures were determined by X‐ray diffraction. Crystal data: monoclinic, space groupP2/nwith cell dimensions ofa= 17.809(4) Å,b= 13.938(4) Å,c= 17.984(4) Å, β=107.14°,Z=4,V= 4266.2 Å2.RandRware 0.043 and 0.053, respectively. The results obtained by spectral analysis are consistent with those of the str

ISSN:1001-604X    

DOI:10.1002/cjoc.19920100606

出版商:Wiley‐VCH Verlag GmbH&Co. KGaA, Weinheim    

年代:1992

数据来源: WILEY

摘要:

AbstractThe retention behavior of high performance ion chromatography using binary eluants is given. The relationship between log(tR) and log(1/[E]) is linear, which has been demonstrated experimentally with mixed anion solution.

ISSN:1001-604X    

DOI:10.1002/cjoc.19920100607

出版商:Wiley‐VCH Verlag GmbH&Co. KGaA, Weinheim    

年代:1992

数据来源: WILEY

摘要:

AbstractAs a model for acetyl‐α‐chymotrypsin, 2‐(2'‐benzimidazolyl)phenyl acetate was synthesized in a good yield and its hydrolytic kinetics has been studied in buffer solutions at 45'C within a wide pH range (0.65–8.80). The measured pseudo‐first‐order rate constants (kobs) at different pH values conform well with the data derived from the proposed theoretical model. It is shown that in an acidic solution of medium strength (pH = 2.0–3.0), the ester is hydrolyzed via intramolecular general acid catalysis by benzimidazolium cation; while at pH values near neutrality (pH = 5.5–7.0), this ester is hydrolyzed via intramolecular general base catalysis by neutral benzimidazole. These findings are discussed and the activation parameters of the hydrolysis reaction we

ISSN:1001-604X    

DOI:10.1002/cjoc.19920100608

出版商:Wiley‐VCH Verlag GmbH&Co. KGaA, Weinheim    

年代:1992

数据来源: WILEY

摘要:

AbstractDirect and sensitized photolyses of 3‐methyl‐3‐(4′‐biphenylyl)‐1‐butene gave 1,1‐dimethyl‐2‐(4′‐biphenylyl)cyclopropane as primary product and 2‐methyl‐4‐(4′‐biphenylyl)‐1‐butene as secondary product with quantum yields of 7.6×10−3and 5.6×10−3, respectively. On direct photolysis, the triplet reactant rearranged with a quantum yield of 4.4×10−3and is more reactive than the singlet. The exceptionally low photoreactivity shows that the excitation energy is largely localized on the biphenylyl portion but

ISSN:1001-604X    

DOI:10.1002/cjoc.19920100609

出版商:Wiley‐VCH Verlag GmbH&Co. KGaA, Weinheim    

年代:1992

数据来源: WILEY

摘要:

AbstractTwo new sterpurene sesquiterpenes, 4,12‐dihydroxysterpurene (1) and 5,12‐dihydroxysterpurene (3), have been isolated fromStereum purpureum, and identified mainly on the basis of mass spectra and extensive nuclear magnetic resonance spectrometry, especially two‐dimensiona

ISSN:1001-604X    

DOI:10.1002/cjoc.19920100610

出版商:Wiley‐VCH Verlag GmbH&Co. KGaA, Weinheim    

年代:1992

数据来源: WILEY