摘要:

AbstractThe influence of the presence of trimethylsilyl and triphenylsilyl groups in substituents of anthraquinone on the properties of anthraquinone vat, acid, and dispersion dyes was investigated.

ISSN:0018-019X    

DOI:10.1002/hlca.19710540112

出版商:WILEY‐VCH Verlag GmbH    

年代:1971

数据来源: WILEY

摘要:

AbstractThe values of ΔG, ΔHand ΔSfor the formation of the mixed 1:1:1 lanthanide EDTA complexes with the anions of 8‐hydroxyquinoline‐5‐sulfonic acid, iminodiacetic acid and nitrilotriacetic acid were determined by pH‐titrations and a direct calorimetric method. These thermodynamic data are discussed and compared with those for the formation of the Ln(III)EDTA complexes. Contrary to current opinion it is concluded that all trivalent lanthanide aquoions have the same coordination number in dilute solution. However, in the series of the lanthanide EDTA complexes the coordination number changes between Sm and Tb. In this region, equilibria occur between two types of EDTA complexes with different numbers of coordinated water molecules:The corresponding equilibrium constants could be evaluated. The coordination number changes also in many other Ln complexes along the lanthanide series, and similar equili

ISSN:0018-019X    

DOI:10.1002/hlca.19710540113

出版商:WILEY‐VCH Verlag GmbH    

年代:1971

数据来源: WILEY

摘要:

AbstractThe photoelectron spectrum (PE. spectrum) of barrelene (bicyclo[2.2.2]octatriene,4) is recorded and the first four bands are correlated with orbitals obtained with the MINDO/2‐SCF procedure. The structural changes accompagnying the ionisation process4→4+are qualitatively derived from the features of the top‐occupieda′2(π) MO of4, which shows complete σ‐π separation. The vibrational pattern of the corresponding PE. band 1. as well as complete energy‐minimisation of the geometries of4and4+support the conclusion that4is a rather strained molecule. The interaction of the three πbonds in4are discussed in terms of‘through‐space’and‘through‐bond’interaction with lower lying σ‐orbitals. It is found that the lat

ISSN:0018-019X    

DOI:10.1002/hlca.19710540114

出版商:WILEY‐VCH Verlag GmbH    

年代:1971

数据来源: WILEY

摘要:

AbstractThe complex kinetics found for the hydrolysis of 1, 3, 5‐trichloro‐s‐triazine in 9/91% (v) acetone/water at 10.0°C have been evaluated as a function of the hydroxyl ion and the acetate ion concentration using an analogue computer. The kinetics are consistent with a nonsteady state mechanism in which the primary intermediate anion is protonated giving a neutral species whose concentration goes through a maximum during the course of the reaction. This secondary intermediate forms the final product by deprotonation and release of a chloride ion. The product itself can undergo a second (reversible) deprotonation.In dimethylsulfoxide the analogous intermediate of the hydrolysis of 1, 3‐dimethoxy‐5‐chloro‐s‐triazine can be identified by analysis of the NMR.

ISSN:0018-019X    

DOI:10.1002/hlca.19710540115

出版商:WILEY‐VCH Verlag GmbH    

年代:1971

数据来源: WILEY

摘要:

AbstractLes fréquences de résonance quadripolaire du noyau35CI dans les complexes du tri chlorure de bore avec une variété de donneurs organiques ont été mesurées à 77 K. Quoique ces fréquences dans l'accepteur soient assez peu sensibles à la nature du ligand, la tendance observée est en accord avec d'autres mesures du pouvoir donneur des ligands. Certains des ligands étudiés ici contiennent un atome de chlore et les changements de fréquence amenés par la complexation sont également en accord avec les résultats prévus. Le trichloracetonitrile et le dichloracétonitrile réagissent avec le trichlorure de bore pour donner un composé d'addition sur la triple liaison do groupementCN plutǒt qu'un complexe donneur‐accepteur. Ce comportement est clairement mis en évidence par la spectroscopi

ISSN:0018-019X    

DOI:10.1002/hlca.19710540116

出版商:WILEY‐VCH Verlag GmbH    

年代:1971

数据来源: WILEY

摘要:

Abstract1The pyrolysis of elemol (1) in the presence of benzoic orp‐nitrobenzoic acid, and of elemyl‐p‐nitrobenzoate (3) was studied. From the many products formed, the compounds6, 7, 8, 10, 11, 14, 15and18were isolated and identified. On the basis of systematic experiments in the elemol (1) and dihydrogeijerene (26) series the sequence of the formation of these products could be determined. Several factors influencing the compositions of the pyrolysis mixtures are discussed.2The products of pyrolysis of both series [elemol (1) and dihydrogeijerene (26), respectively] were catalytically hydrogenated, yielding the saturated hydrocarbons34, 35–37, and38–40, respectively.3The synthesis of racemic dihydrogeijerene (26) was achieved starting from germac

ISSN:0018-019X    

DOI:10.1002/hlca.19710540117

出版商:WILEY‐VCH Verlag GmbH    

年代:1971

数据来源: WILEY

摘要:

AbstractFrom bulbs ofEucomis autumnalis Graeb (Liliaceae)autumnariol (1) and autumnariniol (4), two new substituted dibenzo‐α‐pyrones have been isolated. Their structures have been determined mainly using spectroscopic techniques. In the NMR. spectra of1and4and related model compounds an unusuallong‐range coupling over six bonds has been demons

ISSN:0018-019X    

DOI:10.1002/hlca.19710540118

出版商:WILEY‐VCH Verlag GmbH    

年代:1971

数据来源: WILEY

摘要:

AbstractThe stability constants of the 1 :1 complexes of trimethylenediamine‐N, N, N′ N′ tetraacetate ‘TMTA’ with rare earth trivalent cations have been checked. The heats involved in complex formation have been determined.The thermodynamic data show a similar trend as for those of the EDTA complexes, but the discontinuities in the plots ΔHvs. 1/r and ΔS vs. 1/r are displaced towards lower values of 1/r.A change of the coordination number and of the number of coordinated water molecules for the complexes along the series La3+ – Lu3+is suggested. The simultaneous presence in solution of species differing only in the number of bonded H2O for some members of the series has been confirmed by spectrophotometric measurements in the temperature range2to70°.All facts support the conclusion that in dilute solution all SEIIIaquo ions exhibit the same coord

ISSN:0018-019X    

DOI:10.1002/hlca.19710540119

出版商:WILEY‐VCH Verlag GmbH    

年代:1971

数据来源: WILEY

摘要:

AbstractIn a series of 21m‐/p‐substituted N‐methylpyridinium salts, N‐methyl proton, carbon‐13 and pyridinium nitrogen‐14 chemical shifts were determined by heteronuclear double resonance, and partly in the case of the14N nucleus and the methyl protons by direct measurement. In a few compounds the quadrupole relaxation times proved to be too short for the14N coupling to be detected. This problem was overcome by adequately rising the sample temperature. For all three nuclei a marked dependence of the chemical shifts on the nature of the substituent could be established. Increased nitrogen π‐electron density shifts the resonances towards higher fields. In the case of the14N shieldings, this tendency is attributed to changes in the paramagnetic screening term, whereas for13C and1H an interpretation is given in terms of a neighbour anisotropy contribution. The latter explanation is based on the observation that the calculated carbon and hydrogen charge densities show no significant variations throughout the series. Excellent shift correlations were obtained withHammettsubstituent constants when σ+‐values were used for donor substituents. A similar substituents, dependence could be observed for the direct13CH methyl coupling constants, whose magnitude increases with decreasing nitrog

ISSN:0018-019X    

DOI:10.1002/hlca.19710540120

出版商:WILEY‐VCH Verlag GmbH    

年代:1971

数据来源: WILEY

摘要:

AbstractThe two hexamines (H2NCH2CH2)2N(CH2)nN(CH2CH2NH2)2, «penten» (n = 2) and «ptetraen» (n=3) have been investigated as chelating agents for COIII (preparative Study) and some of the divalent metal ions (potentiometric and calorimetric studies). Both amines function as sexadentate ligands for CoIII, CoIIand NiII, but one of the terminal aminogroups is much easier detached from the metal in case of M (penten)v+than in case of M(ptetraen)v+, thus revealing more strain in the fivemembered chelate rings of the girdle plane of the «penten» complexes. On the other hand, the sixmembered chelate ring in M(ptetraen)v+is more strained than the five‐membered ring comprising the tertiary nitrogen atoms of M(penten)v+CuIIand ZnIIcoordinate with both ligands only 5 of the 6 basic nitrogen atoms present. Both hexaamines function as sexadentates again with MnII, but the metal is coordinated with a molecule of water in addition to the 6 nitrogen atoms in the «penten» complex in contrast to the «ptetraen» complex. The thermodynamic functions for the protonation of the hexamines and for the addition of metal ions in aqueous solution are understood in almost every detail. The dielectric shielding of the charges of the reactants exerted by the solvent has to be taken into account; it is reduced by electrostriction as well as by an increase in temperature. It is shown that the approach of charges of equal sign oft

ISSN:0018-019X    

DOI:10.1002/hlca.19710540121

出版商:WILEY‐VCH Verlag GmbH    

年代:1971

数据来源: WILEY