Molecular modeling in organic chemistry: Correlating odors with molecular structure

1989 ◽  
Vol 66 (4) ◽  
pp. 275 ◽  
Author(s):  
Kenny B. Lipkowitz
Keyword(s):  
Organic Chemistry ◽  
Molecular Structure ◽  
Molecular Modeling

Application of Laser-Excited Raman Spectroscopy to Organic Chemistry. III. A Skeletal Frequency Correlation for Cedrane-Type Molecules

1970 ◽  
Vol 24 (6) ◽  
pp. 591-595 ◽  
Author(s):  
D. W. Mayo ◽  
Stanley K. Freeman
Keyword(s):  
Organic Chemistry ◽  
Molecular Structure ◽  
Raman Spectroscopy ◽  
Correlation Pattern ◽  
Variable Intensity ◽  
Frequency Correlation

The use of Raman spectroscopy in the determination of complex molecular structure is discussed. For 12 cedranes, five of the seven most intense bands observed between 900 and 500 cm−1 appear in a series of relatively narrow wavenumber ranges, and these are correctable with the cedrane skeleton. A band of variable intensity at ca. 320 cm−1, characterized by a ρ value of 0.2–0.4, may be included in the correlation pattern.

scholarly journals Hybrid Atomic Orbitals in Organic Chemistry. Part 2: Critique of Practical Aspects

2019 ◽  
Author(s):  
Guy Lamoureux ◽  
J. F. Ogilvie
Keyword(s):  
Organic Chemistry ◽  
Molecular Structure ◽  
Critical Survey ◽  
Atomic Orbitals ◽  
Hybrid Orbitals

The importance of hybrid atomic orbitals, in both general and organic chemistry, is reviewed. Every contemporary textbook of organic chemistry introduces the sp3, sp2, sp model, but the suitability of these hybrid orbitals for use in the teaching of molecular structure has been increasingly questioned. Based on a critical survey of the literature, we submit seven practical criteria that deprecate the use of hybrid orbitals in a pedagogical context. We suggest how the teaching of organic chemistry without hybrid orbitals will provide students with an enhanced education.

ANALYSIS OF PURINIC ALKALOIDS BY XRD AND MOLECULAR MODELING METHODS

2021 ◽  
Vol 8 (2021) (1) ◽  
pp. 1-8
Author(s):  
José REGO ◽  
◽  
Jorddy CRUZ ◽  
Marcondes COSTA ◽  
Fabrine ALVES ◽  
...  
Keyword(s):  
Molecular Structure ◽  
Molecular Modeling ◽  
Cross Validation ◽  
Linear Models ◽  
Monoclinic System ◽  
Purine Base ◽  
Crystal Sample ◽  
Modeling Methods ◽  
Statistical Results ◽  
Good Linear Correlation

Theophylline, theobromine and caffeine, are purine-based alkaloids in which the main differentiation in the molecular structure is the presence of methyls, one, two and three, respectively in these substances. This study presents an analysis by XRD and molecular modeling methods of the alkaloid’s caffeine and theobromine. The crystalline structure of caffeine was characterized as a monoclinic system, and the diffractogram of the caffeine crystals showed peaks with regions of greater intensity at 2θ = 11.7616 ° (d = 7.51 Å; I% = 80.13) and 2θ = 11.9416 ° (d = 7.40 Å; I% = 98.14). In the diffractogram of the theobromine crystal sample, peaks of greater intensity occurred in the regions 2θ = 13.4616 ° (d = 6.57 Å; I% = 98.92) and 2θ = 27.0816 ° (d = 3, 28 Å; I% = 67.23). Results obtained by XRD for caffeine and theobromine were compatible with standard cards of the X’Pert High Score Plus® program. The presence of an extra methyl in the structure of the caffeine purine base, suggests, a shift in the values ​​of the angle 2 θ for the main peaks of theobromine, as well as an increase in intensity, mainly in 27.016, theobromine also presents a peak in the region 10.6 which does not occur in caffeine. Statistical results reveal that the linear models for data of peaks of specific angles in 2θ of the samples, presented good linear correlation (R2> 98%) and satisfactory results after the procedure of cross validation. caffeine and theobromine also showed important differences in interactions with adenosine A2AR, particularly in hydrophobic and hydrogen interactions.

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