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Einfluss der Orientierung von Substituenten auf die chemische Verschiebung von 13 C. II. 13 C‐NMR.‐spektroskopische Untersuchung von substituierten Spiro [cyclopropan‐1′,9‐fluorenen]
Author(s) -
Fritz Hans,
Winkler Tammo,
Braun André M.,
Decker Christian
Publication year - 1978
Publication title -
helvetica chimica acta
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.74
H-Index - 82
eISSN - 1522-2675
pISSN - 0018-019X
DOI - 10.1002/hlca.19780610213
Subject(s) - cyclopropane , chemistry , chemical shift , ring (chemistry) , stereochemistry , nmr spectra database , crystallography , spectral line , organic chemistry , physics , astronomy
Effect of the Orientation of Substituents on the Chemical Shift of 13 II. 13 C‐NMR. Study of Substituted Spiro [cyclopropane‐1′, 9‐fluorenes] The 13 C‐NMR. spectra of spiro[cyclopropane‐1′, 9‐fluorenes] substituted at the cyclopropane ring have been assigned, largely with the aid of selective proton decoupling. The effects of the substituents upon the chemical shifts of the aromatic carbons are orientation dependent. the effects of cis‐substituents on γ‐carbon atoms are large and negative (inducing high field shifts), those of trans‐substituents smaller and dependent on the electron donor/acceptor properties of the substituents. The effects on δ‐carbon atoms in close proximity of the substituents are large and positive; they are interpreted in terms of electric field effects.