Diamagnetic anisotropy of aromatic

Pauling, L. The diamagnetic anisotropy of aromatic molecules. J. Chem. 

Pauling, L. (1936) The diamagnetic anisotropy of aromatic molecules. /. Chim. Phys., 4,... 

The idea of a ring current goes back to early work by Pauling who suggested that the diamagnetic anisotropy of aromatic molecules is due to the 2pz electrons, which are free to move under the influence of an electric field from a carbon atom to its adjacent carbon atom. 

Your work on conjugated circuits reminds me of a paper that I wrote on the diamagnetic anisotropy of aromatic molecules. Journal of Chemical Physics 4, 673 (1936)... Again let me thank you for writing to me. 

Substances dissolved in aromatic solvents generally give signals at higher fields than when dissolved in aliphatic solvents. These effects are attributed to the diamagnetic anisotropy of aromatic rings, and are more significant when... 

Values of the diamagnetic anisotropy of benzene and other aromatic hydrocarbon molecules are calculated on the basis of the assumption that the p, electrons (one per aromatic carbon atom) are free to move from carbon atom to adjacent carbon atom under the influence of the impressed fields. When combined with the assumed values for the contributions of the other electrons (-2.0X 10-6 for hydrogen, —4.5 X10 c for aromatic carbon, — 6.0XlO-6 for aliphatic carbon) these lead to principal diamagnetic susceptibilities of molecules in approximate agreement with the available experimental data. The diamagnetic anisotropy of graphite is also discussed. 

Pauling, L. (1979). Diamagnetic anisotropy of the carbonate ion in calcite, aragonite, strontianite and witherite and of other non-cyclic planar aromatic groups with resonance structures. Zeit. Krist. 150, 155-61. 

In the latter hydrocarbon, the two methyl groups are partially lying above the plane of an aromatic ring, similarly, to (184 e), and hence they experience an shielding effect by the diamagnetic anisotropy of the system. The methyl signal in the lH NMR spectrum, as with (184e), is found at r = 8.28 ppm. 

The hypothesis that a solute-solvent conformation depicted in (66) is responsible for the spectral non-equivalence allows explanation of the experimental data. In this conformation, the aromatic rings of the amine and the carbinol overlap, the methine proton being shielded by the diamagnetic anisotropy of the rings. The more distant trifluoromethyl group experiences comparatively less shielding. In the enantiomer shown in (67) the positions of the trifluoromethyl group and the... 

---