APPLICATIONS OF THE MOLECULAR-ORBITAL TREATMENT OF THE PERTURBED BENZENE RING TO SOME HOMO- AND HETEROCYCLICS AND THEIR DERIVATIVES
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Date
1951
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Ohio State University
Abstract
The general formulas found in the previous paper are applied to some derivatives of homo-and heterocyclics containing nitrogen and methl groups. It is shown that it is possible to find a consistent system of perturbation parameters for explaining some of the properties of these compounds. This means that, by using the same set of semiempirical parameters, we get a tolerably good agreement between theory and experiment in treating the energy transitions of the mobile electrons, the dipole moments, the substituation rates, etc., for compounds containing one or more nitrogen atoms in the ring (pyridine, pyrimidine, pyrazine, and pyridazine), for the methl substituents of benzene (toluene and the xylenes), and for the ``combined'' compounds (the picolines). When using parameters in agreement with the empirical data for the d***ole moments, we have found that for compounds containing nitrogen there are almost always $\pi-\pi$ transitions even in the region where the bands recently have been $described^{1}$ as being exclusively of the $n-\pi$ type.
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$^{1}$ J. R. Platt, J. Chem. Phys. 19, 101 (1951) M. Kasha, Trans. Far. Soc., 1951 (in press)
Author Institution: Duke University
Author Institution: Duke University