Aromatic Compounds and Benzene Derivatives

2016 ◽  
pp. 815-892
Keyword(s):  
Aromatic Compounds ◽  
Benzene Derivatives

NMR-spektroskopische Untersuchungen über zwischenmolekulare Wechselwirkungen bei Benzolderivaten und Pyrrol / NMR-Spectroscopic Investigation of the Intermolecular Reactions of Benzene Derivatives and Pyrrole

1969 ◽  
Vol 24 (11) ◽  
pp. 1365-1370 ◽  
Author(s):  
H.-H. Perkampus ◽  
U. Krüger ◽  
W. Krüger
Keyword(s):  
Dipole Moment ◽  
Temperature Dependence ◽  
Aromatic Compounds ◽  
Spectroscopic Investigation ◽  
Chemical Shifts ◽  
Benzene Derivatives ◽  
Intermolecular Reactions ◽  
Proton Chemical Shifts

The proton chemical shifts of aromatic compounds are strongly concentration dependent. Moreever, for molecules with a dipole moment a temperature dependence of the proton chemical shifts is observed. For hemellitone, p-methylanisole, o-chlortoluene, p-chlortoluene, pyrrole and N-methyl-pyrrole the enthalpies of a dipole-dipole association between -0,7 and -1,8 Kcal could be estimated by NMR measurements combined with the temperature dependence in the whole range of the molefraction (0 → 1).

scholarly journals Thiophene, Furans, and Related Aromatic Compounds from Eupatorium heterophyllum

2011 ◽  
Vol 6 (3) ◽  
pp. 1934578X1100600
Author(s):  
Yoshinori Saito ◽  
Koji Takiguchi ◽  
Xun Gong ◽  
Chiaki Kuroda ◽  
Motoo Tori
Keyword(s):  
Aromatic Compounds ◽  
Chemical Transformations ◽  
Benzene Derivatives ◽  
Spectroscopic Analyses

A thiophene, two furans, a dihydro furan, and two acetylenic benzene derivatives were isolated from the roots of Eupatorium heterophyllum collected in China. Structures were established on the basis of spectroscopic analyses as well as chemical transformations.

Acylation of aromatic substrates with ketenes. II. Hammett–Brown studies on substituted aromatic compounds

1980 ◽  
Vol 58 (18) ◽  
pp. 1939-1946 ◽  
Author(s):  
K. R. Fountain ◽  
Pamela Heinze ◽  
Dave Maddex ◽  
Greg Gerhardt ◽  
Paul John
Keyword(s):  
Complex Formation ◽  
Aromatic Compounds ◽  
Benzene Derivatives ◽  
Chloride Complexes ◽  
Line Segments ◽  
Aromatic Substrates ◽  
Π Complex ◽  
Partial Rate ◽  
Inorganic Complexes ◽  
Vinyl Cation

Competition reactions using dimethylketene (DMK) – aluminum chloride complexes on a variety of substituted benzene derivatives gave partial rate factors. The logs of these Pfx values when plotted versus σ+ values gave two line segments of ρ = −6.59 for less active substrates, and ρ = −0.92 for more active substrates. Similar results were found for diphenylketene (ρ = −9.47 and −1.07).These results were rationalized by analogy to vinyl cation alkylations. A pair of π complexes (outer then inner) occur between initial approach of the reagent and final, product-determining π-complex formation. In one of these complexes the C=C bond of the ketene complex may be able to back-bond in a manner similar to that found in inorganic complexes of CO and metals.

scholarly journals Structure of 1.2-diphenylbenzene (C 18 H 14 )

1937 ◽  
Vol 161 (907) ◽  
pp. 493-504 ◽  
Keyword(s):  
Aromatic Compounds ◽  
Bond Distance ◽  
Benzene Derivatives ◽  
Single Bond ◽  
X Ray ◽  
Planar Configuration ◽  
Atomic Nuclei ◽  
Fundamental Reason ◽  
The Individual ◽  
Conjugated Compounds

Benzene derivatives, as a particular example of conjugated compounds, tend to form plane molecules unless some kind of hindrance exists. Until recently it was thought that the carbon-carbon linkage between the individual nuclei in, say, diphenyl was a single bond, capable of free rotation, and that the co-planar configuration was the most likely because it was the most symmetrical (Adams and Yuan 1933). X-ray analysis has shown in fact that the molecules of diphenyl (Dhar 1932), p -diphenylbenzene (Pickett 1933) and p -diphenylbiphenyl (Pickett 1936) are all plane, but the observation that the carbon-carbon internuclear distance is less than the normal single-bond distance indicates a measure of conjugation in the internuclear bond as a more fundamental reason for the molecular planarity. X-ray analysis has further shown that in aromatic compounds of all varieties of structure, carbon atoms in separate molecules do not approach nearer to each other than about 3·5 A (between centres) (Robertson 1934), owing to van der Waals repulsion. There are, therefore, in such compounds as 1.2-diphenylbenzene, two forces opposing one another: (1) The tendency for the whole of the atomic nuclei to lie in one plane, because of conjugation in the interatomic bonds. (2) The tendency for atoms in the substituted phenyl groups to repel each other. The latter force is exhibited even in such a compound as durene (1. 2. 4. 6-tetramethylbenzene) for which X-ray analysis has shown (Robertson 1933) that the adjacent methyl groups repel each other in the plane of the molecule, so that there is a straining of the normal valency angles.

“Carbo-aromaticity” and novel carbo-aromatic compounds

2015 ◽  
Vol 44 (18) ◽  
pp. 6535-6559 ◽  
Author(s):  
Kévin Cocq ◽  
Christine Lepetit ◽  
Valérie Maraval ◽  
Remi Chauvin
Keyword(s):  
Aromatic Compounds ◽  
Theoretical Studies ◽  
Benzene Derivatives ◽  
Triple Bonds ◽  
Recent Advances ◽  
Definition Of ◽  
Experimental And Theoretical Studies

Recent advances in experimental and theoretical studies ofcarbo-benzene derivatives, along with the proposition of a generalization of the definition of aromaticity to the two-membered π-rings of triple bonds, suggest relevance for the notion of “carbo-aromaticity”.

Carbon-13 substituent-induced chemical shifts in benzene derivatives: Substituted anilines

1991 ◽  
Vol 56 (2) ◽  
pp. 368-385 ◽  
Author(s):  
Miloš Buděšínský ◽  
Dan Johnels ◽  
Ulf Edlund ◽  
Otto Exner
Keyword(s):  
Aromatic Compounds ◽  
Nmr Spectra ◽  
Chemical Shifts ◽  
Benzene Derivatives ◽  
Substituted Anilines ◽  
Ring Carbon ◽  
Close Resemblance ◽  
Substituent Constants

Carbon-13 NMR spectra are reported for 59 meta- and para-substituted anilines in deuterochloroform or in its mixture with hexadeuterodimethyl sulphoxide. The substituent-induced chemical shifts (SCS) of ring carbon atoms in position 4 correlate well with dual substituent parameters (DSP). In the remaining positions correlations are not satisfactory with any kind of known substituent constants. There is, however, a close resemblance between SCS in the same position of meta- and para-substituted anilines and even in other series of aromatic compounds.

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