ISSN:
0749-1581
Schlagwort(e):
13C NMR
;
1H NMR
;
9-Methylenefluorenes
;
Substituent effects
;
Substituent-induced chemical shifts
;
Chemistry
;
Analytical Chemistry and Spectroscopy
Quelle:
Wiley InterScience Backfile Collection 1832-2000
Thema:
Chemie und Pharmazie
Notizen:
The two 13C NMR methyl signals of the sterically congested 9-benzylidene-1,8-dimethylfluorene (1a) have the surprisingly small separation of only 0.37 ppm; for 9-benzylidene-2,7-dimethylfluorene the corresponding methyl separation is 0.04 ppm. An alternative analysis of 1a with respect to 1,8-dimethylfluorene shows that the perturbing syn-phenyl substituent has caused a downfield ( + 0.47 ppm) 13C shift but an upfield 1H shift ( - 0.97 ppm) of the compressed 1-CH3 group. For further comparisons, NMR assignments were also made for 2,7-dimethylfluorene, 1,8-dimethylfluoren-9-one and 2-(1,1-dimethylethyl)-3,3-dimethyl-1-phenylbut-1-ene.
Zusätzliches Material:
2 Tab.
Materialart:
Digitale Medien
URL:
http://dx.doi.org/10.1002/mrc.1260310415
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