摘要:

AbstractResonance Raman spectra of the species [Co(salen)], [Co(salen)]2and [Co(salen)(py)] were obtained both from the solids and from CHCl3solutions. These spectra show a large number of bands in the 100–1750 cm−1region which are assigned to vibrational modes of the salen ring. Oxygenated complexes having the general form μ‐peroxo‐[Co(salen)(L)]2O2, with ligand L being DMSO, py, DMF, pyO or no L and occupying the axial positiontransto the dioxygen, gave resonance Raman spectra with many bands throughout the region 100–1750 cm−1. The ν(CoO) and ν (OO) wavenumbers in these complexes have been assigned by means of oxygen‐18 substitution. Force constants for the OO and COO bonds in the DMF complex have the values 380 and 247 N m−1, respectively. The effect of changing the ligand L on the observed wave numbers is interpreted in terms of both σ and π‐donor effects through the metal. Band intensity excitation profiles demonstrate that the O22−→ Co3+CT transition occurs at ˜370±10 nm for the complexes containing ligands L and at 580 nm for the complex with no L. Resonance function plots of Raman band intensities are interpreted in terms of the relative values of the OO bond orders which are shown to vary with the ligand L as follows: py>pyO>DMF>DMSO. This order is, however, at variance with

ISSN:0377-0486    

DOI:10.1002/jrs.1250110202

出版商:John Wiley&Sons, Ltd.    

年代:1981

数据来源: WILEY

摘要:

AbstractResonance Raman spectra have been determined at −60°C for a series of complexes of the general form [(L)(D2H2)CoO2Co(D2H2)(L)], where D is the dianion of dimethylglyoxime and L is pyridine, (C2H5)3N, (CH3)2S, (C6H5)3P, (C6H5)3As and (C6H5)3Sb, these ligands being coordinatedtrans‐axially to the dioxygen. The spectra show bands in the region 810–835 cm−1which are assigned to the ν(OO) mode and the ν(CoO) mode is assigned in the region 550–575 cm−1. The effect on the observed ν(OO) wavenumber of changing the ligand L shows how σ‐ and π‐donor effects of the ligands are transmitted through the metal. The ν(OO) band intensity excitation profile demonstrates that the O2−→ Co3+CT transition is to be assigned at 550 nm. Comparison between the nature of the cobalt‐oxygen binding in the oxime and those of the cya

ISSN:0377-0486    

DOI:10.1002/jrs.1250110203

出版商:John Wiley&Sons, Ltd.    

年代:1981

数据来源: WILEY

摘要:

AbstractResonance Raman spectra have been determined for the μ‐peroxo complex [(en)2CoO2Co(en)2]4+and μ‐peroxo‐μ‐hydroxo complex [(en)2CoO2(OH)Co(en)2]3+, where en = ethylenediamine. The spectra show bands at 799 and 795 cm−1, assigned to the ν(OO) mode in each complex, respectively, while the ν(CoO) mode occurs at ∼590 cm−1. However, two strong bands occur at 494 and 534 cm−1in the spectrum of the μ‐peroxo complex and only one strong, broad band at 530 cm−1occurs in the spectrum of the μ‐peroxo‐μ‐hydroxo complex. These are assigned to ν(CoN) modes in both complexes. The spectra of the complexes [(L‐his)2CoO2Co(L‐his)2] and [(L‐his)2CoO2(OH)Co(L‐his)2]−show bands at 811 and 805 cm−1assigned to the ν(OO) mode, respectively, while the ν(CoO) mode is assigned at 600 and 590 cm−1, respectively. The ν(CoN) modes in both complexes are assigned at 530 and 493 cm−1. These bands are much stronger in the spectrum of the μ‐peroxo than in that of the μ‐peroxo‐μ‐hydroxo complexes. However, the obvious differences between the Raman spectra of the μ‐peroxo and μ‐peroxo‐μ‐hydroxo complexes are not in the ν(OO) and ν(CoO) bands but rather in the lower wavenumber ν(CoN) region. The ν(OO) band intensity excitation profiles demonstrate that the O2−2→Co3+charge transfer transition occurs at ∼352 and 360 nm for [(en)2CoO2Co(en

ISSN:0377-0486    

DOI:10.1002/jrs.1250110204

出版商:John Wiley&Sons, Ltd.    

年代:1981

数据来源: WILEY

摘要:

AbstractResonance and pre‐resonance Raman spectra of solids, aqueous and D2O solutions of adriamycin and daunomycin are reported. The Raman bands are due to the chromophore anthraquinone and are coupled with the first electronic π‐π*transition of the molecules. All the observed Raman bands have been assigned to vibrations of the chromophore. Resonance enhancement for most of the Raman bands has been observed in relation to the π‐π*transition. Spectra taken at different pH values show interesting Raman intensity changes owing to a shift of the π‐π*transition towards longer wavelengths. An π‐π*transition has been assigned to the shoulder near 500 nm of the absorption spectra of the molecules on the basis of the intensity changes of some Raman bands involving the ca

ISSN:0377-0486    

DOI:10.1002/jrs.1250110205

出版商:John Wiley&Sons, Ltd.    

年代:1981

数据来源: WILEY

摘要:

AbstractUrea:n‐paraffin inclusion compounds have been formed through sonification of urea with pure paraffin liquids. Raman microprobe spectra of individual microcrystals (5–50 μm in size) of these materials are interpreted in terms of a non‐planar conformation for the included paraffins. A series oftransandgauchebonds is shown to yield a conformation of the included alkane that preserves the full symmetry of the hexagonal urea host. The urea host lattice spectrum thereby shows additional sharp bands consonant with a more highly ordered host lattice. These observations are contrasted to the case of thetrans‐planar conformation normally encountered and verified in this work for urea:n‐paraffin inclusion compounds prepared fro

ISSN:0377-0486    

DOI:10.1002/jrs.1250110206

出版商:John Wiley&Sons, Ltd.    

年代:1981

数据来源: WILEY

摘要:

AbstractRaman spectra of RbHSO4have been recorded in the temperature range from 6 K to the melting point, 480 K. Analysis of the spectra show that the second order phase transition, at 264 K, Is of the order‐disorder type. No soft mode was found. The evolution of the ν(OH) mode frequency with temperature, is consistent with a change of orientation of the hydrogen bonds connecting the disordered SO3O(H) groups. The spectra are also consistent with the existence of a prototype phase which had been assumed to explain the pseudo‐orthorhombic symmetry of the paraelectric and ferroelectri

ISSN:0377-0486    

DOI:10.1002/jrs.1250110207

出版商:John Wiley&Sons, Ltd.    

年代:1981

数据来源: WILEY

摘要:

AbstractLow‐frequency Raman scattering (20–400 cm−1) of aqueous solutions of 5′‐monophosphates of uridine (UMP), cytidine (CMP), guanosine (GMP) and of adenosine (AMP) are studied by construction of a quantityR(ν). The frequencles for intensity maxima below 100 cm−1depend upon the protonization or the purine and pyrimidine rings, but not upon ionization of the phosphate groups. An assignment to modes very similar to corresponding nucleoside modes

ISSN:0377-0486    

DOI:10.1002/jrs.1250110208

出版商:John Wiley&Sons, Ltd.    

年代:1981

数据来源: WILEY

摘要:

AbstractThe IR and Raman spectra of the mixture 4HNO3· H2O in crystal, glassy and liquid states have been investigated in the frequency range 4000–50 cm−1. The crystal is the oxonium trihydrogentetranitrate where the oxonium ion is practically free (ν(OH) = 3480 and 3385 cm−1). In the trlhydrogentetranitrate ion the charge is not localized. In the glassy and liquid states, four species have been characterized: (1) the oxonium trihydrogentetranitrate; (2) the free molecular association H2O …︁ (HONO2) (νOH(H2O)= 3550 cm−1and νOH(HNO3)=2930 cm−1); (3) the free ionic pair (H2OH)+…︁(ONO2)−(ν(OHO)= 2700 cm−1, ν1(NO3−)=1030 cm−1) and (4) free

ISSN:0377-0486    

DOI:10.1002/jrs.1250110209

出版商:John Wiley&Sons, Ltd.    

年代:1981

数据来源: WILEY

摘要:

AbstractThe Raman band of the ν1vibrational mode of SO42−has been measured in aqueous solutions of Na2SO4and (NH4)2SO4at 5–80°C, and analysed from the stochastic point of view. The band shape is approximately symmetric, but cannot be reproduced by a Lorentzian curve. The vibrational relaxation is caused by a random modulation of very low frequency from surrounding water. The vibrational correlation time for the ions is not sufficiently long to make allowance for the Markovian process of relaxation, compared with the correlation time for the bath, that is water. The vibrational correlation function appropriate for these ions is pro

ISSN:0377-0486    

DOI:10.1002/jrs.1250110210

出版商:John Wiley&Sons, Ltd.    

年代:1981

数据来源: WILEY

摘要:

AbstractThe Raman spectra of the degenerate bands of cyclohexane and cyclohexane‐d12have been recorded at medium resolution in the gas phase. The computer simulation of the band contours has allowed to determine the Coriolis coupling constants ζ19, ζ20, ζ21, ζ22, ζ23, a

ISSN:0377-0486    

DOI:10.1002/jrs.1250110211

出版商:John Wiley&Sons, Ltd.    

年代:1981

数据来源: WILEY