The transmission of polar effects. Part VII. A proton magnetic resonance spectra study of substituted mesitylenes, durenes, anthracenes, and triptycenes

Abstract

The chemical shifts of the ringprotons in a series of monosubstituted mesitylenes and durenes,and of the 10-protons of a series of 9-substituted triptycenes and anthracenes have been measured in dimethyl sulfoxide, acetone, 2-methoxyethanol, and carbon tetrachloride. The solvent dependence of the substituent chemical shifts has been analyzed by linear free energy relations. The systems all show similar dependence which increases with increasing dielectric constant of the solvent. This does not result from the field effect being transmitted through the medium, but appears to arise from the formation of a hydrogen-bonded interaction between the solvent and the hydrogen of the solute. The substituent chemical shifts appear to arise from contributions from substituent field, resonance, magnetic anisotropy, and solvent effects.

Spin trapping with 9-nitrosotriptycene

“…The large error limits reflect the current level of precision of these measurements (2). Experimental Materials 9-Nitrotriptycene was prepared from 9-nitroanthracene by the method of Bowden et al (7) and converted into 9-nitrosotriptycene by the method of Theilacker and Beyer (5). Di-9-triptoyl peroxide was derived from triptoic acid by the method of Bartlett and Greene (8).…”

“…Les spectres de rpe des adduits de spin sont simples mais ils montrent une influence marquée de la température en raison d'une rotation limitée. Le nitrosotriptycene capte les radicaux alkyles primaires avec une constante de vitesse d'environ 2 χ 10" 7 Lmol"' s" 1 dans le benzène à 40°C.…”