Modeling Substituent-Dependence of the Twist and Shielding in a Series of 4-Substituted N-(4-Nitrobenzylidene)anilines

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Title:Modeling Substituent-Dependence of the Twist and Shielding in a Series of 4-Substituted N-(4-Nitrobenzylidene)anilines
Creators:
Proks, Vladimír
Holík, Miroslav
Journal or Publication Title:
Collection of Czechoslovak Chemical Communications, 69, 8, pp. 1566-1576
Uncontrolled Keywords:<i>Ab initio</i> calculations, Conformation analysis, Azomethines, <sup>1</sup>H NMR chemical shifts, Imines, Correlation analysis, NMR spectroscopy, Substituent effects

Abstract

A series of 15 4-substituted <i>N</i>-(4-nitrobenzylidene)anilines was synthesized and studied by <sup>1</sup>H NMR spectroscopy. Their ab initio calculated geometries and the shielding as expressed by aromatic ring currents were used in correlation analysis. The geometries were fully optimized using density functional theory B3LYP/6-311G** approaches. For the determination of the ring current contribution to the shielding of azomethine hydrogens H<sub>α</sub> was used direct ab initio calculation of the chemical shielding in a model system. Experimental chemical shift values free of these contributions were successfully correlated with increments <i>a</i><sub>p</sub> of chemical shift for monosubstituted benzenes. In the same manner, the contribution of the anisotropy of C=N double bond to H<sub>m</sub> hydrogen were calculated and values of the H<sub>m</sub> chemical shift free of this contribution were successfully correlated with increments of chemical shift <i>a</i><sub>m</sub>. <p>

Title:Modeling Substituent-Dependence of the Twist and Shielding in a Series of 4-Substituted N-(4-Nitrobenzylidene)anilines
Creators:
Proks, Vladimír
Holík, Miroslav
Uncontrolled Keywords:<i>Ab initio</i> calculations, Conformation analysis, Azomethines, <sup>1</sup>H NMR chemical shifts, Imines, Correlation analysis, NMR spectroscopy, Substituent effects
Divisions:Life and Chemical Sciences > Institute of Organic Chemistry and Biochemistry > Collection of Czechoslovak Chemical Communications
Journal or Publication Title:Collection of Czechoslovak Chemical Communications
Volume:69
Number:8
Page Range:pp. 1566-1576
ISSN:0010-0765
E-ISSN:1212-6950
Publisher:Institute of Organic Chemistry and Biochemistry
Related URLs:
URLURL Type
http://dx.doi.org/10.1135/cccc20041566UNSPECIFIED
ID Code:2294
Item Type:Article
Deposited On:06 Feb 2009 17:17
Last Modified:06 Feb 2009 16:17

Citation

Proks, Vladimír; Holík, Miroslav (2004) Modeling Substituent-Dependence of the Twist and Shielding in a Series of 4-Substituted N-(4-Nitrobenzylidene)anilines. Collection of Czechoslovak Chemical Communications, 69 (8). pp. 1566-1576. ISSN 0010-0765

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