Enclathration by a Halogenated Host: Structures, Polymorphism, Kinetics, and Guest Exchange

The host tetrakis (p-bromophenyl) ethylene forms inclusion compounds with 1,4-dioxane (chiral and racemic polymorph pair), cyclohexanone, dimethyl sulfoxide, and 3-pentanone. Their structures have been elucidated, and their nonbonded host-guest interactions have been analyzed. The thermal decomposition of the two Host center dot dioxane polymorphs yielded activation energies of 84 kJ.mol(-1) and 90 kJ.mol(-1). Guest exchange kinetics have been measured for the Host.dimethyl sulfoxide -> Host.acetone by differential scanning calorimetry and for the Host center dot cyclohexanone -> Host.3-pentanone by powder X-ray diffraction. The latter reaction is deceleratory and follows the decreasing area law, with a half-life of 42 min at 25 degrees C.

Automated summary

This study found that the host tetrakis (p-bromophenyl) ethylene can form inclusion compounds with 1,4-dioxane, cyclohexanone, dimethyl sulfoxide, and 3-pentanone, with their nonbonded host-guest interactions analyzed. The thermal decomposition of the two host center · dioxane polymorphs yielded different activation energies, and guest exchange kinetics were measured for different host-guest pairs. The reaction between host center · cyclohexanone and host · 3-pentanone was found to be deceleratory and follow the decreasing area law.