ISSN 1017-2548(Print)
ISSN 2234-8530(Online)
Volume 25, Number 2
JKCSEZ 25(2)
April 20, 1981 

Ultraviolet spectrophotometric investigations have been carried out on the systems of mesitylene with iodine, bromine, iodine monochloride and iodine monobromide in carbon tetrachloride. The results reveal the formation of the charge transfer complexes of the type, C6H3(CH3)3·X2 or C6H3(CH3)3·IX (X denotes halogen atoms). The equilibrium constants were obtained in consideration of that absorption maxima due to the formation of the charge transfer complexes shift to blue with the increasing temperatures. Thermodynamic parameters, ΔH, ΔG and ΔS for the formation of the charge transfer complexes were calculated from these values. These results indicate that the relative stabilities of the mesitylene complexes at each temperature decrease in the order, ICl > IBr > I2 > Br2. This order may be a measure of their relative acidities toward mesitylene, which is explaned in terms of the relative polarizabilities of halogen molecules and the relative electronegativities of halogen atoms. These results combined with previous study of this series indicated that the relative stabilities of the polymethylbenzene complexes with iodine increase in the order Benzene < Toluene < Xylene < Mesitylene Thus, analysis of these findings is discussed.