A SPECTROSCOPIC STUDY OF SOME CBR4 COMPLEXES

Results are presented from an investigation of the Raman and ultraviolet spectra of CBr4 in solutions containing benzene and from an ultraviolet investigation of the tetrahydrofuran-CBr4 system. The changes occurring in the ultraviolet spectrum for these systems have been analyzed quantitatively to determine the formation constants for one-to-one donor-CBr4 complexes. Relative Raman intensity values are presented for three of the four CBr4 fundamentals in benzene-CBr4 solutions. These data were analyzed and interpreted in terms of complex formation, and the formation constants from this analysis were compared to those from the ultraviolet study. The two sets of formations constants agree, leading to the conclusion that formation of the same chemical species causes the observed changes in both the ultraviolet and the Raman spectra of CBr4 in benzene. The changes in the Raman intensities for CBr4 in solution with benzene are analyzed in terms of changes in the bond polarizability parameters, with results similar to those found earlier for solutions of CCl4 in donor solvents. The nature of the benzene-CBr4 interaction is discussed, and it is concluded that it is probably primarily electrostatic.