Cotton-Mouton effect, magnetic anisotropy and charge delocalization of 2,4,6-tris(dimethylamino)-1,3,5-triazine. Comparison with 1,3,5-triazine

Measurements of the dilute-solution Kerr and Cotton-Mouton constants of 1,3,5,-triazine and 2,4,6-tris(dimethylamino)-1,3,5-triazine (hexamethylmelamine) as solutes in cyclohexane are reported and analysed to obtain experimental values of the optical-frequency polarizability anisotropies and the magnetic anisotropies of these molecules. The magnetic anisotropies are separated into diamagnetic and temperature-independent paramagnetic contributions, and the role of the quadrupole moment in relation to previously reported stereospecific interactions between hexamethylmelamine and hexafluorobenzene in discussed. From a comparison of the derived out-of-plane magnetizability components with the values predicted for hypothetical structures in which the electron distribution is completely localized, it is inferred that 1,3,5-triazine exhibits only about one-tenth but 2,4,6-tris(dimethylamino)-1,3,5-triazine at least one-half of the delocalization that characterizes benzene. © 1991.