摘要:

AbstractThe [I2CN]−ion, previously only known in aqueous solution, has been isolated as its caesium salt; and the previously unknown [BrICN]−ions [ClICN]−have been isolated as their caesium salts. The Raman and IR vibrational spectra of these three caesium salts have been investigated in detail and indicate that the halide ions coordinate to the I atom of ICN to form linear (C∞ν) [X—I—CN]−ions (X=I, Br or Cl), contained in a centrosymmetric unit cell. ThisC∞νstructure is supported by a normal coordinate analysis f

ISSN:0377-0486    

DOI:10.1002/jrs.1250090402

出版商:John Wiley&Sons, Ltd.    

年代:1980

数据来源: WILEY

摘要:

AbstractExperimental studies of the variation of intensity with excitation wavenumber of somea1vibrational bands in the Stokes Raman spectra of the following molecules are reported: quinoxaline (1,4‐diazanaphthalene), phthalazine (2,3‐diazanaphthalene) and pyridazine (1,2‐diazabenzene). The results are discussed in terms of the Albrecht–Hutley theory of pre‐resonance Raman intensities and the electronic states involved in the pre‐resonance enhancement

ISSN:0377-0486    

DOI:10.1002/jrs.1250090403

出版商:John Wiley&Sons, Ltd.    

年代:1980

数据来源: WILEY

摘要:

AbstractExperimental studies of the variation of intensity with excitation wavenumber of various vibrational bands in the Stokes Raman spectra of the following molecules are reported: naphthalene, pyrazine, phenazine, cinnoline and quinazoline. The results are discussed in terms of the Albrecht–Hutley theory of pre‐resonance Raman intensities and the electronic states involved in the pre‐resonance enhancement ident

ISSN:0377-0486    

DOI:10.1002/jrs.1250090404

出版商:John Wiley&Sons, Ltd.    

年代:1980

数据来源: WILEY

摘要:

AbstractThe Raman spectra of gaseous, liquid and solid cyclopentylamine and the infrared spectra of the gaseous and solid phases have been recorded. Raman depolarization ratios and infrared band contours in the gas phase indicate that cyclopentylamine exists primarily with agaucheorientation of the —NH2group, and the torsional fundamental for this conformer has been observed at 232 cm−1. In the solid state the temperature characteristics in certain spectral regions are consistent with the existence of two low temperature phases, and the higher temperature phase appears to exist over a range of approximately only 7°C. A complete vibrational assignment is proposed, and the structural features of cyclopentylamine are discu

ISSN:0377-0486    

DOI:10.1002/jrs.1250090405

出版商:John Wiley&Sons, Ltd.    

年代:1980

数据来源: WILEY

摘要:

AbstractThe IR spectra (1400 cm−1to 160 cm−1) of the gases at ambient temperature and the Raman spectra (below 1400 cm−1) of the liquids near −196°C are reported for CF3OF and CF3OCl. All fundamentals are assigned underCssymmetry and the results of a normal coordinate analysis are presented. The assignments of Smardzewski and Fox are adopted with one exception for both CF3OF and CF3OCl: the CF3rock ofA″ symmetry is assigned near 430 cm−1and the two bands between 200 cm−1and 300 cm−1are assigned to anA′ fundamental, involving CF3rocking and COX bending and a Δν=2 transition in the CF3torsion. An extra band at 548 cm−1in the Raman spectrum of liquid CF3COl near −196°C is assigned to a CF3OCl ⃛Cl2complex. The values of the force constantsd(OX) for CF3OX molecules are suggested to be near those for X2O molecules. More than half the normal modes ofA′ symmetry show extensive mixing of symmetry coordinates. In some of these cases the symmetry coordinate for which the normal mode is named is the largest but not the dominant contributor to the potential energy distribution, while in others this symmetry coordinate is not even the largest contributor to the potential energy distribution. No normal modes ofA′ symmetry are present in which ν(CO), δs(CF3), δ(COX), or δ(CF3) symmetry coordinates are dominant, and the mode conventionally labeled asv(CO) should be labeled as νs(CF3). For the remainingA′ normal modes and all theA″ normal modes, the symmetry coordinate for which the normal mode is named is domin

ISSN:0377-0486    

DOI:10.1002/jrs.1250090406

出版商:John Wiley&Sons, Ltd.    

年代:1980

数据来源: WILEY

摘要:

AbstractPyridine‐3,5‐d2and pyridine‐3,4,5‐d3have been prepared. Isotopic constitution and label specificity of each of several preparations were verified by mass spectrometry and proton NMR. Liquid phase Raman and both liquid and vapor phase infrared spectra of these molecules are reported. Vibrational assignments consistent with frequency sum and product rule constraints are proposed. The relative rates of base‐catalyzed exchange of hydrogen with deuterium for the ring positions of pyridine‐N‐oxide were estimated during the course of the synthetic work. It is found that the 2 and 6 positions exchange very readily, that the 3 and 5 positions exchange slowly, and that the 4 position exchange

ISSN:0377-0486    

DOI:10.1002/jrs.1250090407

出版商:John Wiley&Sons, Ltd.    

年代:1980

数据来源: WILEY

摘要:

AbstractPyridine‐2,3,5,6,‐d4has been prepared. The isotopic composition and label specificity of each of three preparations were verified by mass spectroscopy and proton NMR. The liquid phase Raman and the liquid and vapor phase infrared spectra of pyridine‐2,3,5,6‐d4and pyridine‐d5at room temperature are reported. The vibrational spectra of these compounds are completely analyzed and a summary of the assignment for all eightC2νdeuterium labeled pyridine

ISSN:0377-0486    

DOI:10.1002/jrs.1250090408

出版商:John Wiley&Sons, Ltd.    

年代:1980

数据来源: WILEY

摘要:

AbstractRaman spectra of nitrocyclopropane were recorded from 4000 to 30 cm−1for the liquid and solid states. Infrared spectra were recorded from 4000 to 180 cm−1for vapor phase and matrix isolated states. The low frequency torsional mode is located at 101 cm−1in the liquid state (102 cm−1in the solid state) and correlates well with the 84 cm−1value for the vapor phase which is predicted on the basis of a torsional combination band in the infrared vapor phase spectrum. The calculated barrier to internal rotation for the vapor phase is 1645±50 cm−1, 4.70±0.15 kcal mol−1. A vibrational assignment is proposed for the first time and it supports structural arguments that there is significant pseudo‐conjugation between the cyclopropane ring orbitals and the substituent NO2group. Finally, a detailed temperature study reveals no appreciable spectral change; hence, nitrocyclopropane appears to exist as a singleCsconformer over the ra

ISSN:0377-0486    

DOI:10.1002/jrs.1250090409

出版商:John Wiley&Sons, Ltd.    

年代:1980

数据来源: WILEY

摘要:

AbstractThe Raman spectrum of a single crystal of monoclinic B‐type (C 2h3) gadolinium sesquioxide is presented. The low temperature polarization studies allowed the unambiguous attribution of 20 among the 21 normal modes expected according to theC2hfactor group analysis predicti

ISSN:0377-0486    

DOI:10.1002/jrs.1250090410

出版商:John Wiley&Sons, Ltd.    

年代:1980

数据来源: WILEY

摘要:

AbstractFrom the Raman spectrum of aqueousL. caseidihydrofolate reductase the protein backbone was found to be predominantly random‐coil (∽45%), ∽30% β‐sheet and ∽25% α‐helical conformations. The Raman spectrum of the binary methotrexate‐dihydrofolate reductase complex showed the polypeptide backbone to be predominantly random‐coil (∽55%) and β‐sheet (∽38%) conformers with a very small percentage of α‐helix conformation. A change in the tyrosine doublet intensity (I860/I835) were observed upon binary complex formation. This change in intensity ratio supports a fluctuation in tyrosine hydrogen bonding environment in DHR upon complex formation. In the methotrexate–dihydrofolate reductase complex the pteridine ring of methotrexate was shown to be protonated. Comparison of the Raman spectra of the solution of the native enzyme and binary methotrexate complex supported the hypothesis of significant conformational changes in theL. caseidihydrofolate red

ISSN:0377-0486    

DOI:10.1002/jrs.1250090411

出版商:John Wiley&Sons, Ltd.    

年代:1980

数据来源: WILEY