Vibration Frequencies and Normal Coordinates of Benzo(c)phenanthrene

2001 ◽  
Vol 56 (6-7) ◽  
pp. 499-504
Author(s):  
Rehab M. Kubba ◽  
Muthana Shanshal
Keyword(s):  
Spectroscopic Data ◽  
Normal Coordinate Analysis ◽  
Quantum Mechanical ◽  
Ir Absorption ◽  
Quantum Mechanical Calculations ◽  
Vibration Frequencies ◽  
Normal Coordinate ◽  
Normal Coordinates ◽  
Comparative Relations

Abstract MINDO/3-FORCES quantum mechanical calculations yielded non-planar (C2) geometry of Ben-zo(c)phenanthrene. The result agrees with the majority of published results but disagrees with others in which a planar (C2 V) structure was accepted in order to simplify the analysis of certain spectroscopic data. Vibration frequencies and IR absorption intensities were calculated then, applying the non-planar (C2) structure. A complete normal coordinate analysis for the molecule is reported. Inspection of these coordinates allowed the discovery of some useful comparative relations between them, which are re­ ported in the paper.

Frequencies and Normal Modes of Benz(a)anthracene. A MINDO/3-FORCES Treatment

2001 ◽  
Vol 56 (6-7) ◽  
pp. 493-498
Author(s):  
Rehab M. Kubba ◽  
Muthana Shanshal
Keyword(s):  
Normal Modes ◽  
Normal Coordinate Analysis ◽  
Quantum Mechanical ◽  
Ir Absorption ◽  
Quantum Mechanical Calculations ◽  
Vibration Frequencies ◽  
Normal Coordinate ◽  
First Time

Abstract Quantum mechanical calculations, based on the MINDO/3-FORCES method, of the vibration fre­quencies and IR absorption intensities of benz(a)anthracene are reported and compared with calculated vibration frequencies of that molecule. For the first time a complete normal coordinate analysis for the molecule is reported. Interesting correlations between vibration motions of the same type but different symmetries are reported.

Vibration Frequencies, Normal Coordinates and IR Absorption Intensities of 1-; 1,2-Di-; 1,3-Di- And 1,2,3-Trimethylene Cyclobutane

2005 ◽  
Vol 60 (6) ◽  
pp. 411-418
Author(s):  
Rehab M. Kubba ◽  
S. H. Rida ◽  
A. H. Hanoon
Keyword(s):  
Normal Coordinate Analysis ◽  
Ir Absorption ◽  
Vibration Modes ◽  
Vibration Frequencies ◽  
Mo Calculations ◽  
Normal Coordinate ◽  
Normal Coordinates

SCF-MO calculations of the vibration frequencies and IR absorption intensities, applying the MINDO/3-FORCES method, are reported for the four molecules, mono-, di- (1,2- and 1,3-), and 1,2,3-trimethylene cyclobutane. Normal coordinate analysis of all vibration modes is described for each molecule. The obtained results allow interesting correlations between the frequencies of similar modes as calculated for the different methylene cyclobutanes.

Vibration Frequencies and Normal Coordinates of 3Radialene

2001 ◽  
Vol 56 (6-7) ◽  
pp. 505-508
Author(s):  
Rehab M. Kubba
Keyword(s):  
Normal Coordinate Analysis ◽  
Ir Absorption ◽  
Vibration Frequencies ◽  
Mo Calculations ◽  
Normal Coordinate ◽  
Normal Coordinates ◽  
Central Carbon ◽  
Walsh Model

Abstract SCF-MO calculations of the vibration frequencies and IR absorption intensities of 3radialene are re­ ported. Complete normal coordinate analysis for the molecule was done. The C=C str. frequencies of 3radialene are found to be intermediate between the values for ethylene and acetylene. The results are explained in terms of a modified Förster-Walsh model for the 3ring in which the central carbon atoms show sp hybridization.

scholarly journals Three New Spongian Diterpenes from the Fijian Marine Sponge Spongia sp

2009 ◽  
Vol 4 (3) ◽  
pp. 1934578X0900400 ◽  
Author(s):  
Harald Gross ◽  
Anthony D. Wright ◽  
Uwe Reinscheid ◽  
Gabriele M. König
Keyword(s):  
Molecular Modeling ◽  
Marine Sponge ◽  
Spectroscopic Data ◽  
Chemical Investigation ◽  
Complete Analysis ◽  
Quantum Mechanical ◽  
Quantum Mechanical Calculations ◽  
Fiji Islands ◽  
Combined Strategy ◽  
Spongian Diterpene

Chemical investigation of the marine sponge Spongia sp., collected from the Fiji Islands resulted in the isolation of three new furanoditerpenoids 1-3, along with the known compounds epispongiatriol (4) and 17,19-dihydroxyspongia-13(16),14-dien-2,3-dione (5) While 1 is a new spongian diterpene with a modified oxidation pattern, compounds 2 and 3 represent two new ring A-contracted spongians, displaying a novel and unprecedented nor-spongian carbon skeleton. Despite their labile nature the structures could be established through a combined strategy including complete analysis of spectroscopic data (NMR, MS), molecular modeling and quantum-mechanical calculations.

Synthesis, isolation and characterization of a stable lithium stannenolate. A keto or an enol tautomer?

2021 ◽  
Vol 50 (39) ◽  
pp. 13651-13655
Author(s):  
Roman Bashkurov ◽  
Natalia Fridman ◽  
Dmitry Bravo-Zhivotovskii ◽  
Yitzhak Apeloig
Keyword(s):  
Spectroscopic Data ◽  
Quantum Mechanical ◽  
Quantum Mechanical Calculations ◽  
Isolation And Characterization ◽  
Enol Tautomer

The synthesis and isolation of the first stable lithium stannenolate is reported. Structural and spectroscopic data, in combination with DFT quantum-mechanical calculations, indicate that the stannenolate adopts the keto tautomeric structure.

Normal Coordinate Analysis and Mean Amplitudes of Vibration of Spiropentane

1974 ◽  
Vol 29 (12) ◽  
pp. 1898-1901 ◽  
Author(s):  
B. N. Cyvin ◽  
O. Gebhardt
Keyword(s):  
Electron Diffraction ◽  
Potential Energy ◽  
Spectroscopic Data ◽  
Field Potential ◽  
Normal Coordinate Analysis ◽  
Potential Energy Distribution ◽  
Structure Parameters ◽  
Harmonic Force ◽  
Normal Coordinate ◽  
Mean Amplitudes Of Vibration

Using spectroscopic data and structure parameters observed by electron diffraction, a normal coordinate analysis was performed for spiropentane. Harmonic force field, potential energy distribution and calculated mean amplitudes of vibration are reported. A very satisfactory agreement is found between observed and calculated mean amplitudes of vibration.

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