ISSN:
0749-1581
Schlagwort(e):
1H NMR
;
Hexaphenylbenzene
;
Hindered internal rotation
;
Stereochemistry
;
Isomerization mode
;
Chemical shift increments
;
Chemistry
;
Analytical Chemistry and Spectroscopy
Quelle:
Wiley InterScience Backfile Collection 1832-2000
Thema:
Chemie und Pharmazie
Notizen:
The 1H NMR spectrum of hexakis(3-methoxyphenyl)benzene exhibits a methoxy absorption which looks exactly like a triplet. The spacing between the signals is, however, proportional to rather than independent of the field strength. The aryl H-5 region of this compound and the methyl region of hexakis(3-methylphenyl)benzene display similar field-proportional, triplet-like splittings. This property of meta-substituted hexaphenylbenzenes cannot be explained by either preferential or residual isomerism, even in the presence of many accidental isochronies. A chemical shift model based on the hypothesis that the meta substituents do not disturb the geometry of the hexaphenylbenzene skeleton or the populations of the rotamers explains the spectra in a straightforward manner.
Zusätzliches Material:
3 Ill.
Materialart:
Digitale Medien
URL:
http://dx.doi.org/10.1002/mrc.1260260408
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