摘要:

AbstractWe proposed four types of stabilization mechanisms of anthocyanin in aqueous solutions; (1) self‐association, (2) copigmentation, (3) intramolecular sandwich‐type stacking, and (4) metal chelation associated with self‐association and copigmentation. The driving force of these stackings would be mainly hydrophobic interactions between the aromatic nuclei which are surrounded by hydrophilic sugar moi

ISSN:0009-4536    

DOI:10.1002/jccs.198900001

出版商:WILEY‐VCH Verlag    

年代:1989

数据来源: WILEY

摘要:

AbstractThe quantitative analysis of iron and cobalt in super alloys has been studied. 1,‐10‐Phenanthroline and nitroso‐R salt provide the chromophores for iron(II) and cobalt(II), respectively. The possibility of applying these photometric methods to a relatively complex substance, such as a super alloy, has been evaluated on the bases of precision and accuracy. The absorbance characteristics of metal complexes and the possible interference from foreign ions have also been carefully investigated. The presence of a high concentration of Ni results in a reducation of the amount of 1,10‐phenanthroline available for the formation of ferroin complexes while Mo does not have this effect. The analytical methods have been applied to the super alloys, Inconel 718, Hastelloy X, and Inconel X‐750. The modified 1,10‐phenanthroline photometric method and the standard nitroso‐R salt photometric method give high accuracy and good precision. This illustrates the analytical applicability of these reagents to

ISSN:0009-4536    

DOI:10.1002/jccs.198900002

出版商:WILEY‐VCH Verlag    

年代:1989

数据来源: WILEY

摘要:

AbstractCyclic voltammetric and differential pulse voltammetric characteristics of the oxidation reaction of ferrocene in acetonitrile solvent have been evaluated using a glassy carbon indicator electrode. The redox couple ferrocene/ferricinium ion approaches thermodynamic reversibility in acetonitrile medium in only a low concentration range.

ISSN:0009-4536    

DOI:10.1002/jccs.198900003

出版商:WILEY‐VCH Verlag    

年代:1989

数据来源: WILEY

摘要:

AbstractThe title compound crystallizes in space group P 21/c of the monoclinic system in a cell of dimensions: a = 9.231(2), b = 15.931(2), c = 12.420(2) Å, β = 108.37(1)°. The observed density is 1.60 g/cm3and the density calculated for four molecules in the cell is 1.58 g/cm3. The refinement converged with R = 0.029 and Rw= 0.028 based on 2569 reflections with I>2.5 σ. The molecule has approximate Cssymmetry with a mirror plane roughly containing the central Mo atom and twocis‐carbonyls, C(1)O(1) and C(4)O(4), while bisecting the bidentate, H2CPz2, and twotrans‐carbonyls. The four carbonyls and tine bidentate adopt aquasi‐octahedral arrangement around the Mo atom. The C(NN)2Mo linkage of the (H2CPz′2)Mo fragment is observed to be in the boat form. The twocis‐carbonyls are bent away by the bulky H2CPz′2bidentate giving ∠C(1)‐Mo‐C(4) ≃ 167.3(1)°. The distortion explains the facile allyl bromination and decarbonylation observe

ISSN:0009-4536    

DOI:10.1002/jccs.198900004

出版商:WILEY‐VCH Verlag    

年代:1989

数据来源: WILEY

摘要:

AbstractThree new η2‐acyl complexes, TMo(CO)2(η2‐COR) (T = Tp', Tp'; R= Me, Bun; Tp' = hydridotris(3,5‐dimethyl‐pyrazol‐1‐yl)borate; Tp' = hydridotris(3,4,5‐trimethylpyrazol‐l‐yl)borate) prepared from the corresponding alkyl iodides, RI, and the anions, TMo(CO)−3. The preparation of Et4N+Tp Mo(CO)3−is also described. Using solution IR spectra to monitor the reactions between RI and TMo(CO)3−, it was found that Tp'Mo(CO)2(η2‐COMe) was formed more readily than Tp'Mo(CO)2(η2‐COMe) which was obtained more easily than Tp'Mo(CO)2(η2‐COBun). This finding suggests that the mechanism is probably an ionic substitution rather than a radical mechanism. The different times required for the complete conversion from the anions to TMo(CO)2(η2‐COR) is rationalized in terms of the electro

ISSN:0009-4536    

DOI:10.1002/jccs.198900005

出版商:WILEY‐VCH Verlag    

年代:1989

数据来源: WILEY

摘要:

AbstractFive polymer‐type new compounds‐(η3‐cyclopentadienyl)palladiumchloride (6), (η3‐indenyl) palladiumchloride (7), (η3‐cycloheptatrienyl)palladiumchloride (8), (η3‐phenalenyl)palladiumchloride (9) and (1,2,3‐η3‐4,5,6,7‐η4‐cyclopheptatrienyl)(palladium‐chloride)(tricarboryl Iron) (10) have been prepared from the reaction of Na2PdCl4with 1‐trimethylsilylcyclopentadiene (1), 1‐trimethylsilylindene (2), 1‐trimethylsilyl cycloheptatriene (3), 1‐trimethylsilylphenalene (4) and 1‐trimethylsilylcycloheptatriene tricarbonyl Iron (5) respectively. All the complexes(6)‐(10) are obtained in excellent yield using the improved preparation route. Furthe

ISSN:0009-4536    

DOI:10.1002/jccs.198900006

出版商:WILEY‐VCH Verlag    

年代:1989

数据来源: WILEY

摘要:

AbstractPolyiodide complexes of benzophenone (B) with iodine (I) and alkali iodide (MI, M = Na, K, Rb or Cs) have been prepared from methanol for the first time. The crystals of these complexes (abbreviated BIMI) are in the shape of hexagonal prisms with golden luster sides and black cross sections. BIMI complexes exhibit semiconductive behavior from 250 to 310 K with activation energies of 0.6 to 0.8 eV. Under an applied dc field at room temperature, the longitudinal conductivity of BIMI crystals is in the order of 10−6Scm−1and does not decrease over a period of half an hour, indicating no ionic conductivity in these complexes. In contrast, significant ionic conductivity is observed for benzophenone complexes grown from chloroform. It is concluded that the solvent molecules play an important role in determining the electrical behavior of the resulting benzophenone complexes. The results of conductivity and resonance Raman spectroscopic studies on the entire methanol series of BIMI complexes suggest that a common conduction pathway is probably provided by the polyiodide chains in this new series of benzophenone comple

ISSN:0009-4536    

DOI:10.1002/jccs.198900007

出版商:WILEY‐VCH Verlag    

年代:1989

数据来源: WILEY

摘要:

AbstractThe electron density distribution of KMnO4is studied by the X‐ray diffraction method. Potassium permanganate crystalizes in an orthorhombic space group Pbnm with cell parameters a=7.3661(7), b=9.0610(9), c=5.6458(3)Å, Z=4. The molecular symmetry is CSwith the Mn atom and two oxygen atoms located on the plane perpendicular to the c‐axis. A set of accurate diffraction data were measured at 115K. Subsequent refinements and Fourier syntheses were performed. The electron density distribution is expressed in terms of the deformation density. The Mn‐O bondings are well characterized, the lone pair electron density at the oxygen atoms is also observed. The density near the Mn nucleus seems to be very sensitive to changes of the scale factor and extinction coefficient. Several types of extinction corrections were made. The features of the Mn‐O bond are comparable to the theoretical density calculated at the ab‐initio level, and to the experimental density of the isoelectronic compound K2CrO4. However, the experimental density of KMnO4is not so well reproduced in the vicinity of

ISSN:0009-4536    

DOI:10.1002/jccs.198900008

出版商:WILEY‐VCH Verlag    

年代:1989

数据来源: WILEY

摘要:

AbstractThe benzoylformyl Pd(II) complex, Pd(PPh3)2(Cl)(COCOPh), thermally decomposes to the corresponding benzoyl complex by the loss of CO. The predominant route of decarbonylation is led by a reversible dissociation of a phosphine ligand. The disappearance of the benzoylformyl complex in solutions follows first order kinetics not only in the existence of excess PPh3but also in the absence of added PPh3. Through the treatments of both preequilibrium and the steady state approximations to the kinetic data, the rate constants of the intramolecular acyl migration, k1and k2; as well as the equilibrium constant and the individual rate constants of the reversible phosphine dissociation step, K, kdand kd, were determined in CHCl3. The activation parameters for kd, beingΔH‡= 25.4 Kcal Mol−1,ΔS‡= 15.9 eu,ΔG‡= 20.7 Kcal Mol−1;and for k−d, beingΔH‡= 13.0 Kcal Mol−1,ΔS‡= −7.9 eu,ΔG‡= 15.4

ISSN:0009-4536    

DOI:10.1002/jccs.198900009

出版商:WILEY‐VCH Verlag    

年代:1989

数据来源: WILEY

摘要:

AbstractNet signs of edge‐signed graphs obtained for different choices of degenerate eigenvectors of an adjacency matrix are shown to become equal with a simple weighting procedure. However, in a few cases, this simple procedure is found to yield orderings of the eigenvectors based on the weighted net signs which are different from the orderings based on the eigenvalue

ISSN:0009-4536    

DOI:10.1002/jccs.198900010

出版商:WILEY‐VCH Verlag    

年代:1989

数据来源: WILEY