scholarly journals Electronic Indices of Cations of Monosubstituted Benzene Derivatives by omega- Technique

1971 ◽  
Vol 19 (10) ◽  
pp. 2178-2180
Author(s):  
YOSHIO SASAKI ◽  
MIYOKO SUZUKI
Keyword(s):  
Benzene Derivatives ◽  
Monosubstituted Benzene

Carbon-13 Substituent-Induced Chemical Shifts: Monosubstituted Benzene Derivatives

1992 ◽  
Vol 57 (3) ◽  
pp. 497-507 ◽  
Author(s):  
Otto Exner ◽  
Miloš Buděšínský
Keyword(s):  
Benzene Ring ◽  
Nmr Spectra ◽  
Chemical Shifts ◽  
The Other ◽  
Correlation Equations ◽  
Benzene Derivatives ◽  
Complex Mechanism ◽  
Monosubstituted Benzene ◽  
Resonance Effects ◽  
Other Hand

Carbon-13 NMR spectra of twelve monosubstituted benzene derivatives were measured in deuterochloroform. Together with the literature data a set of 35 systematically chosen substituents was obtained on which some thirty correlation equations were tested. As anticipated only substituent chemical shifts (SCS) in the position 4 are controlled by inductive and resonance effects, and can be correlated by dual substituent parameters (DSP). For the other positions DSP were not successful and more sophisticated equations are not much telling. On the other hand, the direct relations between two series of SCS are usually more precise and simple to understand. It is concluded that SCS in benzene ring need not be controlled by too complex mechanism but simply by different factors than by inductive and resonance effects.

Bond angles and bond lengths in monosubstituted benzene and ethene derivatives: a comparison of computational and crystallographic results

2002 ◽  
Vol 58 (5) ◽  
pp. 877-883 ◽  
Author(s):  
Otto Exner ◽  
Stanislav Böhm
Keyword(s):  
Substitution Effect ◽  
Benzene Derivatives ◽  
Monosubstituted Benzene ◽  
Bond Angles ◽  
Bond Lengths ◽  
Bond Alternation ◽  
Structural Database ◽  
Azo Derivatives ◽  
Strong Deformation ◽  
Small Deformations

Bond angles and bond lengths in 29 monosubstituted benzene derivatives and in the same number of ethene derivatives were calculated at the B3LYP/6-311+G(d,p) level. Angle deformations in benzene derivatives agree reasonably with those derived statistically from the crystallographic data; in the case of small deformations, the calculated parameters are even more reliable. There is little correlation between geometry and reactivity parameters (σ-constants) in spite of some previous claims. Nevertheless, three components of the substitution effect can be distinguished: (a) strong deformation of the adjoining angles and bonds can be ascribed to changes of hybridization; (b) a weaker effect in the meta and para positions is only partially related to resonance; (c) in the case of unsymmetrical substituents, the symmetry of the benzene ring is also broken – the angular group-induced bond alternation (AGIBA) effect. The latter effect was also confirmed by searches in the Cambridge Structural Database for alkoxy, alkylthio, acyl and azo derivatives.

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