MOLECULAR QUADRUPOLE-MOMENTS, MAGNETIC ANISOTROPIES, AND CHARGE-DISTRIBUTIONS OF BORAZINE, B-TRICHLOROBORAZINE, N-TRIMETHYLBORAZINE, AND B-TRICHLORO-N-TRIMETHYLBORAZINE - COMPARISON WITH BENZENE AND ITS DERIVATIVES

Measurements of the dilute-solution molar Kerr constants, field-gradie nt birefringence constants, and Cotton-Mouton constants of borazine an d three substituted borazines as solutes in cyclohexane or carbon tetr achloride at 25-degrees-C are reported. The observations yield the fir st direct experimental values of the effective polarizability anisotro pies, electric quadrupole moments, and magnetic anisotropies, which ar e important descriptors of the molecular charge distributions. A compa rison of the results for borazine with literature data for benzene sho ws that all three properties have the same signs in the two species bu t that all are considerably smaller in magnitude in borazine than in b enzene. An analysis of the magnetizabilities indicates that the extent of electron delocalization in borazine is only about one-third of tha t in benzene, a conclusion which is consistent with a range of other e vidence.