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Substituenteneffekte auf die NMR‐Spektren von Pentafulvenen . ( 13 C, 13 C)‐NMR‐Kopplungskonstanten ( 1 J (C, C))
Author(s) -
Bircher Hansruedi,
Neuenschwander Markus
Publication year - 1989
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.19890720806
Subject(s) - chemistry , substituent , fulvene , coupling constant , ring (chemistry) , nmr spectra database , chemical shift , crystallography , spectral line , stereochemistry , physics , organic chemistry , particle physics , astronomy
Substituent Effects on NMR Spectra of Pentafulvenes. 13 C, 13 C‐NMR Coupling Constants ( 1 J (C, C)) 1 H‐ and 13 C‐NMR spectra of 6‐monosubstituted pentafulvenes 1 – 8 have been analysed, and 1 J (C, C) coupling constants have been determined from ID‐inadequate spectra of 13 C satellites. It turns out that 13 C, 13 C coupling constants of the ring C‐atoms, and especially J (1,2)/J(3,4) and J (2,3), reflect the extent of π delocalisation in the fulvene ring. With increasing electron‐donating capacity of the substituent R, J (1,2)/J(3,4) values are decreasing, while J (2,3) (and J (1,5)/ J (4,5) as well) are increasing, and linear correlations of Hammett substituent constants σ + and 1 J (C,C) values are obtained.