摘要:

In 1970 Lintvedt and Kernitsky1, from a study of the optical spectra of fluorine substituted acetylacetonate complexes, reported that CF3, substitutents on the chelate ring appear to destabilize the occupied energy levels relative to CH3. These results seem to be in direct contradiction with the results of ionization studies2,3,4,5which indicate that CF3substitution stabilizes the occupied energy levels. In an attempt to resolve this dilemma, we have investigated the hydrogen-bonded cis enolone forms of acetylacetone, trifluoroacetylacetone, and hexafluoroacetylacetone with a theoretical molecular orbital method which has been relatively successful for both optical spectra and ionization potentials.

ISSN:0038-7010    

DOI:10.1080/00387017808065117

出版商:Taylor & Francis Group    

年代:1978

数据来源: Taylor

摘要:

The Raman and infrared spectra of 1,4-dithiane-1-oxide are reported in the frequency region from 4000 to 130 cm−1, for polycrystall ine samples. The observed bands are assigned on the assumption of a Cs chair form with axial conformation. The fundamental frequencies are discussed and compared with those of 1,4-dithiane, pentanethylene sulfoxide and 1,4-oxathiane-4-oxide, The vibrational coupling among skeletal and S=0 deformations is discussed.

ISSN:0038-7010    

DOI:10.1080/00387017808065118

出版商:Taylor & Francis Group    

年代:1978

数据来源: Taylor

摘要:

During oxidation of 2,3-epoxytetralene by DMSO in the presence of oxygen(1) beside the trans-2,3-tetralenediol, β-naphtol and 2,3-naphtalenediol a crystalline compound (m.p. 199°-200°C), identified as the unknown 3-hydroxy - 1,2-(2',3'-naphtoxy)-naphtalene I (Fig. 1)was obtained:The structure of this diether was determined by spectroscopic methods. The Uv spectrum with max 225.8 - 226.8 nm (log σ = 4.94), ma 279.5 -28035 nm (log σ = 3.88), max 336.5 nm (log σ 3.67) is quite similar to that of β -naphtol (2). Its IR spectrum (KBr) discs differs from that of β naphtol although absorptions due to similar structural fragments, like the intermolecular H-bond interactions of OH groups of aromatic rings (3370 - 3340 cm− 1and 3070 cm− 1) and a single aromatic hydrogen atom (815-810 cm− 1) are being observed.

ISSN:0038-7010    

DOI:10.1080/00387017808065119

出版商:Taylor & Francis Group    

年代:1978

数据来源: Taylor

摘要:

In the fluorescence spectra only morphine exhibits large red shifts of the maxima on increasing solvent polarity. In the phosphorescence spectra, phenol, anisole, and 3-methoxyphenol exhibit large red shifts of the maxima on going from nonpolar to polar solvents. For the latter, the results are interpreted in terms of charge-transfer-to-solvent (CTTS) transitions. For morphine, 2- and 4-methoxyphenol, the phosphorescence maxima occur at long wavelengths in both nonpolar and polar solvents, and this is interpreted in terms of CTTS and intramolecular charge transfer processes. The red-shift of the morphine fluorescence band on going to polar solvents is similarly interpreted as a combination of CTTS and intramolecular charge transfer transitions.

ISSN:0038-7010    

DOI:10.1080/00387017808065120

出版商:Taylor & Francis Group    

年代:1978

数据来源: Taylor

摘要:

IR-absorption spectra of M2AF6hexafluorocomplexes (M-Na, K, Rb, Cs and NH4; A=Si, Ge, Sn) were obtained and intergrated intensities of bands assigned to stretching vibrations of AF6ions were measured. The reasons for the influence of exchange of the central atom and an outer-sphere cation on the intergrated intessities of vibration bands are discussed. It was found that the ammonium ion does not fit into the earlier established pattern of intensity dependence on cation size. Analysis of the frequencies v3(AF6) suggeste that this is coused by the presence in (NH4)2AF6of hydrogen bonds N-H F of different strength.

ISSN:0038-7010    

DOI:10.1080/00387017808065121

出版商:Taylor & Francis Group    

年代:1978

数据来源: Taylor

摘要:

Energy transfer by excitons is now well established in films and solutions of aromatic polymers. Excitons in disordered systems can be considered as electronically excited states, which are transferred between the light absorbing groups in a random hopping process (the same is true in molecular crystals if, because of thermal vibrations, the coherence length of the exciton waves approaches the lattice constant and consequently the band model of the excitons breaks down).

ISSN:0038-7010    

DOI:10.1080/00387017808065122

出版商:Taylor & Francis Group    

年代:1978

数据来源: Taylor

摘要:

The paper presents experimental results of studies on the temperature dependence of integrated intensities of vibrational bands corresponding to3(GeF6) in M2GeF6IR-spectra. It is shown that unlike Na2GeF6, Rb2GaF6, and Cs2GeF6, where the dependence of intensity on temperature is monotonous, in the case of K2GeF6there exist anomalous temperature ranges of 220-240 and 150-170 K, where the intensity of a band, corresponding to3(GeF2-6) changes abruptly. The study of heat evaluation, heat capacity, unit cell parameters, and intensities of selective reflexes in K2GeF6X-ray diffraction patterns indicates the presence in this compound, as distinguished from others in the seris considerod, of phase transitions of the first order. On the basis of IB,19F NNR, X-rat and calorimetric data, a possible mechanism of polymorphic transformation is discussed.

ISSN:0038-7010    

DOI:10.1080/00387017808065123

出版商:Taylor & Francis Group    

年代:1978

数据来源: Taylor

摘要:

The contribution refers to the temperature dependence of IR-absorption spectra (NH4)2AF6(A - Si and Ge). It is found that with temperature decreasing, the integrated intensities of the bands corresponding to anion fundamentals, increase, while those of cation, decrease. An explanation is given to the phenomena detected, which is based on variations in the strength of the outer-sphere interaction with the temperature, and subsequent redistribution of electron density.

ISSN:0038-7010    

DOI:10.1080/00387017808065124

出版商:Taylor & Francis Group    

年代:1978

数据来源: Taylor

摘要:

E.S.R method was applied to investigate some copper (II) aroylhydrazone complexes. From the experimental spin - Hamiltonian parameters; symmetry, bonding character and electron delocalization were determined. Complexes exhibited a changing fraction of the metal 4s character in their |x2- y2> ground state.

ISSN:0038-7010    

DOI:10.1080/00387017808065125

出版商:Taylor & Francis Group    

年代:1978

数据来源: Taylor

摘要:

This is a scanned image of the original Editorial Board page(s) for this issue.

ISSN:0038-7010    

DOI:10.1080/00387017808065116

出版商:Taylor & Francis Group    

年代:1978

数据来源: Taylor