Library

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    Electronic Resource
    Electronic Resource
    Infrared spectrum, ab initio calculations, barriers to internal rotation and structural parameters for methyl nitrite (1990)
    s.l. : American Chemical Society
    The @journal of physical chemistry 〈Washington, DC〉 94 (1990), S. 4029-4039 
    Details
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology , Physics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1021/j100373a028
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Infrared spectra, vibrational assignment and ab initio calculations for 2,2,2-trifluoroethanimidamide (1990)
    Springer
    Structural chemistry 1 (1990), S. 473-480 
    Details
    ISSN: 1572-9001
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The infrared spectra of gaseous and solid 2,2,2-trifluoroethanimidamide, CF3(NH2)C=NH, have been recorded from 4000 to 80 cm−1. A vibrational assignment for the normal modes is proposed based on group frequencies and normal coordinate calculations utilizing C1 symmetry. The structures for both the cis [hydrogen atom of the =NH group is cis to the NH2 group] and trans geometric isomers have been determined from ab initio Hartree-Fock gradient calculations employing the GAUSSIAN-82 program with the 3–21G basis set. The most stable conformer at this level of calculation is found to be a C1, structure with a partially rotated CF3 group and the hydrogen atom of the imine group trans to the NH2 group. The calculated structural parameters have only very small differences between the conformers. Barriers to internal rotation for the NH2 and CF3 groups and vibrational frequencies have been calculated for the C1 form. The results of this investigation are compared with similar data on some corresponding molecules.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00671234
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Raman spectra and ab initio calculations for methyl nitrite and methyl-d3 nitrite (1990)
    Chichester [u.a.] : Wiley-Blackwell
    Journal of Raman Spectroscopy 21 (1990), S. 615-628 
    Details
    ISSN: 0377-0486
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The Raman (4000-10 cm-1) and infrared (4000-80 cm-1) spectra of methyl nitrite, CH3ONO, and methyl nitrite-d3 were recorded in the gas and solid phases. Additionally, the Raman spectra of the pure liquids were recorded and qualitative depolarization values were obtained. Support for the interpretation of these new data is provided by ab initio calculations using the 6-31G* basis set. Complete equilibrium geometries have been determined for both conformers, as well as structures for every 30° rotation about the N—O bond. These calculations give a cis/trans barrier of 4015 cm-1 (11.5 kcal mol-1), a trans/cis barrier of 3504 cm-1 (10.0 kcal mol-1) and an enthalpy difference between conformers of 511 cm-1 (1.5 kcal mol-1) with the cis form being more stable. From a variable temperature Raman study of liquid methyl nitrite-d3 it is concluded that the cis form is also more stable in this phase with an enthalpy difference between conformers of 262 ± 3 cm-1 (750 ± 9 cal mol-1). A complete assignment of the vibrational fundamentals is proposed based on band contours, depolarization values, group frequencies and shift factors for the two isotopomers. These assignments are supported by normal coordinate analyses using the ab initio force fields to obtain frequencies and potential energy distributions for both conformers.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jrs.1250210914
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    Raman spectra, vibrational assignment, structural parameters and ab initio calculations for ethyl nitrat (1990)
    Chichester [u.a.] : Wiley-Blackwell
    Journal of Raman Spectroscopy 21 (1990), S. 635-644 
    Details
    ISSN: 0377-0486
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Raman spectra (4000-10 cm-1) of gas, liquid and solid ethyl nitrate were recorded. The qualitative depolarization values were obtained from the spectrum of the liquid. A vibrational assignment for the normal modes is proposed based on depolarization values, group frequencies and normal coordinate calculations. The structures for the trans and gauche conformers have been determined from ab initio Hartree-Fock gradient calculations using the Gaussian-82 program with both the 3-21G and 6-31G* basis sets. From this calculation at the 6-31G* level, the energy difference between the more stable trans conformer and the higher energy gauche conformers was found to be 474 cm-1 (1.36 kcal mol-1) with a gauche dihedral angle (CCON) of 79°. The trans to gauche and gauche to gauche barriers are 990 cm-1 (2.83 kcal mol-1) and 3152 cm-1 (9.01 kcal mol-1), respectively. Barriers to internal rotation for the CH3 and NO2 groups were also obtained from ab initio calculations. For the trans conformer the values are 1304 cm-1 (3.73 kcal mol-1) and 2702 cm-1 (7.73 kcal mol-1) and for the gauche conformer they are 1161 cm-1 (3.32 kcal mol-1) and 2758 (7.89 kcal mol-1) for the CH3 and NO2 barriers, respectively. Normal coordinate calculations were also performed for both conformers utilizing force fields calculated from the 3-21G basis set which support the vibrational assignments. The results of this investigation are compared with similar data on some corresponding molecules.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jrs.1250211003
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 5
    Electronic Resource
    Electronic Resource
    Raman and infrared spectra, normal coordinate calculations and vibrational assignment for 1,1,1,3,3,3-hexafluoro-2-propanimine (1989)
    Chichester [u.a.] : Wiley-Blackwell
    Journal of Raman Spectroscopy 20 (1989), S. 473-481 
    Details
    ISSN: 0377-0486
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The Raman (4000-10 cm-1) and infrared (4000-50 cm-1) spectra of gaseous and solid 1,1,1,3,3,3-hexafluoro-2-propanimine, (CF3)2 C=NH, were recorded. Additionally, the Raman spectrum of the liquid was recorded and qualitative depolarization values were obtained. A complete vibrational assignment for the normal modes utilizing Cs symmetry is proposed based on band contours, depolarization values and group frequencies. The assignment is supported by a normal coordinate calculation utilizing a modified valence force field to calculate the frequencies and potential energy distribution of the normal modes. A CF3 torsional mode was observed in the Raman spectrum of the liquid at approximately 60 cm-1, from which a periodic barrier of 5.0 kcal mol-1 (1 kcal = 4.184 kJ) was calculated. The results are compared with similar data for some corresponding molecules.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jrs.1250200802
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...