Solution and solid carbon-13 magnetic resonance study of the conformation of 9,10-dihydroanthracene and its 9,10-methylated derivatives
The /sup 13/C NMR chemical shifts of the 9,10-methylated 9,10-dihydroanthracenes have been obtained, both in the traditional manner in solution and in the solid state by use of cross polarization and magic angle spinning techniques. In addition, the temperature dependence of the solution chemical shifts was measured from about -70 to 40/sup 0/C. Chemical shift effects resulting from methyl substitution are discussed. A nonlinear-least-squares regression analysis was performed on the variable-temperature methyl shift for three of the compounds demonstrating unequally weighted conformational averaging, and the relevant thermodynamic and chemical shift parameters are presented. Both solid and solution spectra indicate ring flattening when geminal methyls are present. Furthermore, the methyls in the more sterically crowded molecules are in environments which differ substantially from those of the simpler molecules, indicating considerable variety in the conformational features.
- Research Organization:
- Univ. of Utah, Salt Lake City
- DOE Contract Number:
- AC02-78ER05006
- OSTI ID:
- 6197063
- Journal Information:
- J. Am. Chem. Soc.; (United States), Journal Name: J. Am. Chem. Soc.; (United States) Vol. 103:16; ISSN JACSA
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
400301* -- Organic Chemistry-- Chemical & Physicochemical Properties-- (-1987)
ANTHRACENE
AROMATICS
CARBON 13
CARBON ISOTOPES
CHEMICAL SHIFT
CONDENSED AROMATICS
DATA
EVEN-ODD NUCLEI
EXPERIMENTAL DATA
HYDROCARBONS
INFORMATION
ISOTOPES
LIGHT NUCLEI
MAGNETIC RESONANCE
NUCLEAR MAGNETIC RESONANCE
NUCLEI
NUMERICAL DATA
ORGANIC COMPOUNDS
RESONANCE
STABLE ISOTOPES
STRUCTURAL CHEMICAL ANALYSIS
TEMPERATURE DEPENDENCE