On the Magnetic Susceptibilities of Troponoid-System. I : Diamagnetism of Hinokitiol (β-Thujaplicin) and α-Thujaplicin

The diamagnetic susceptibilities of hinokitiol ((β-thujaplicin) and α-thujaplicin in powdered crystal form have been measured and the structures of the tropolone-ring are discussed. The observed molar susceptibilities obtained in the present experiments are -(102±1)×10 for hinokitiol, -(100±3)×10 for α-thujaplicin (colourless, m. p. 34°), and -(97±2)×10 for α-thujaplicin (light yellow, m. p. 24°). These observed data have been compared with calculated values, which were computed by use of the four methods ; the Pascal\u27s additive law, the Slater-Angus method, Langevin\u27s formula referring to the diamagnetism for the planar orbit, and the theory of diamagnetic anisotropy of molecular orbitals (London\u27s method), with the result that there are six π-electrons, within each tropolone-ring of these compounds, which are able to revolve along the closed circuit constructed out of the periphery of seven membered ring. As a necessary consequence of this condition, it follows the ionization between one of the carbon atoms in the ring system and the oxygen atom in the carbonyl group, assuming the former a positive charge and the later a negative one

On the Magnetic Susceptibilities of Troponoid System. II : Diamagnetism of Methyl Ether Derivatives

The magnetic susceptibiilties of tropolone methyl ether (Ia), 2-methoxy-7-bromo-tropone (o-bromo-tropolone methyl ether) (II) and α-thujaplicin methyl ether(III) have been measured by use of the Gouy balance described in the previous article.^ The experimental results (-χ_M×10^6) obtained for (Ia), (II) and (III) are 71, 88 and 105 respectively. The susceptibility of crystalline form of (Ia), i. e., (C_8H_8O_2)_2H_2O (Ib), has been also measured, the result being - 160 ×10^ per mole. It has been shown that the value of ΔK_M, which shows the diamagnetic anisotropy of the tropolone ring belonging to each compound, can be easily derived approximately from the experimental value by the application of the empirical additive rule. The remarkable diamagnetic decrements have been observed in the ΔK_M values, the amounts of which depend upon the kinds of the substituents, i. e., OCH_3, Br and isopropyl groups. The results have shown that the ΔK_M value of (II) is almost zero and that of (Ia) is half the value of tropolone itself

On the Magnetic Susceptibilities of Troponoid-System. I : Diamagnetism of Hinokitiol (β-Thujaplicin) and α-Thujaplicin

The diamagnetic susceptibilities of hinokitiol ((β-thujaplicin) and α-thujaplicin in powdered crystal form have been measured and the structures of the tropolone-ring are discussed. The observed molar susceptibilities obtained in the present experiments are -(102±1)×10 for hinokitiol, -(100±3)×10 for α-thujaplicin (colourless, m. p. 34°), and -(97±2)×10 for α-thujaplicin (light yellow, m. p. 24°). These observed data have been compared with calculated values, which were computed by use of the four methods ; the Pascal\u27s additive law, the Slater-Angus method, Langevin\u27s formula referring to the diamagnetism for the planar orbit, and the theory of diamagnetic anisotropy of molecular orbitals (London\u27s method), with the result that there are six π-electrons, within each tropolone-ring of these compounds, which are able to revolve along the closed circuit constructed out of the periphery of seven membered ring. As a necessary consequence of this condition, it follows the ionization between one of the carbon atoms in the ring system and the oxygen atom in the carbonyl group, assuming the former a positive charge and the later a negative one