The Effect of Solvents on the Formation of Complexes of Benzene with Iodine and with Iodine Monochloride

[摘要] The effect of solvents on the stabilities of the C6H6¡¤I2 complex and the C6H6¡¤ICl complex has been investigated through ultraviolet spectrophotometric measurements. The equilibrium constants obtained at room temperature for the formation of C6H6¡¤I2 complex are 0.090, 0.216 and 0.328 lmole-1 in chloroform, cyclohexane and n-hexane, respectively. The corresponding equilibrium constants at room temperature for C6H6¡¤ICl complex are 0.125, 0.676 and 0.689 lmole-1. These results indicate that the stabilities of the two complexes increase with decreasing dielectric constants of the solvents used, the increase in stability being more rapid in the C6H6¡¤ICl complex than in the C6H6¡¤I2 complex. This may support the conclusion that the dative ionic structures, C6H6+¡¦I2- and/or (C6H6I)+¡¦Cl-, play important roles on the reasonance stabilization of both the C6H6¡¤I2 complex and the C6H6¡¤ICl complex, the roles being more important in the latter complex than in the former complex.

[学科分类] 化学（综合）