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13C13C coupling constants in derivatives of trans-stilbene and tetraphenylethylene. Determination of relative signs II

✍ Scribed by P. E. Hansen; O. K. Poulsen; A. Berg

Publisher
John Wiley and Sons
Year
1976
Tongue
English
Weight
493 KB
Volume
8
Category
Article
ISSN
0749-1581

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✦ Synopsis

Abstract

Magnitudes and signs of ^13^C^13^C coupling constants in compounds of the type Ph^13^CR^1^R^2^^13^CR^1^R^2^Ph have been determined and the results are discussed in a broader context. Two types of coupling constants, J(C‐i, C‐α) and J(C‐i, C‐β), between aromatic carbon atoms and the benzylic carbons, probably with different coupling mechanisms, are considered. Whereas ^2^J(C‐2, C‐α) are always found positive, ^2^J(C‐1, C‐β) in the present compounds are found to be negative or about zero. ^3^J(C‐3, C‐α) has the same sign as ^2^J(C‐2, C‐α). A ^4^J and a ^5^J were observed in trans‐stilbene.

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