Kombinierte 13C- und dynamische 1H-NMR-Untersuchung der π-Elektronenverteilung in NR2-substituierten 4H-Pyran-4-on sowie strukturanalogen Pyrylium- und N-Methylpyridiniumsalzen
✍ Scribed by Prof. Dr. sc. E. Kleinpeter; Dr. sc. R. Spitzner; Chem.-Ing. A. Peters; Prof. Dr. sc. W. Schroth; Prof. Dr. K. Pihlaja
- Publisher
- John Wiley and Sons
- Year
- 1990
- Tongue
- English
- Weight
- 347 KB
- Volume
- 332
- Category
- Article
- ISSN
- 1615-4150
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✦ Synopsis
Combined ^13^C and Dynamic ^1^H‐n.m.r. Investigation of the π‐Electron Distribution in NR^2^‐Substituted Pyran‐4‐one, Analogous Pyrylium‐ and N‐Methylpyridinium Salts
The ^13^C chemical shifts of relevant carbon atoms and the barriers to rotation about the exocyclic partial C,N‐double bonds of a series pyrylium and pyridinium salts have been discussed with respect to the π‐electron distribution. Special polymethine cyanine‐like substructures were shown to control the electronic properties of the compounds studied. C^4^,N barriers to rotation, not obtained earlier due to symmetry reasons, were determined for different NR~2~‐substituents in 2,6‐positions.