NMR Identification of Substitutional Isomers in Chelated Polycyclic Aromatic Systems
Abstract
It seems likely that magnetic resonance methods may be useful in distinguishing between isomers of phenols with chelating substituents. Two aspects by which the isomers may be distin guished on the basis of their high- resolution proton magnetic resonance spectra are: (1) -OH proton chemical shift. In aromatic systems, the shift of a chelated -OH proton relative to the -OH peak in the corresponding parent phenol is quite large. This chemical shift is a linear function of the bond order of bond sub i C sub 2 C with the slope depending somewhat upon the substituent Y. If the shift is measured, then that part of the aromatic nucleus spanned by the chelated structure can be identified. (2) From the chemical shift of the protons in Y. A large part of the chemical shift of a proton, which is situated near an aromatic system, arises from the pielectronic ring currents induced in the aro matic system when the molecule is placed in a magnetic field. It is this effect which leads to the other method of assigning the substituent position in polynuclear aromatic systems.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jun 01, 1963
- Accession Number
- AD0409815
Entities
People
- A. L. Porte
- Herbert S. Gutowsky
Organizations
- University of Illinois Urbana–Champaign