Thermochemistry of molecular complexes. 5. Molecular complexes of I2 with ethylbenzenes andn-alkylbenzenes

The enthalpies of formation and equilibrium constants are reported for molecular complexes of I₂ with five ethylbenzene and ninen-alkylbenzene donor molecules in CCl₄. The wavelength of maximum absorbance for each complex is also reported. For ethylbenzene donor molecules, the formation enthalpy and equilibrium constant for the complexes depend strongly on the number of ethyl groups attached to the benzene ring, but only weakly on the position of the groups. For then-alkylbenzene donor molecules, both the formation enthalpy and equilibrium constant for complex formation are indenpendent of the length of the alkyl chain. These results are consistent with previous observations on weak complexes of I₂ with substituted benzene donors.