Liquid Crystalline Catalysis. Crystal Structure of Allyl Sulfonate Ester (ASE) and its Solid State Reactivity

Abstract

Allyl (p-dimethylamino)benzenesulfonate (ASE) is indefinitely stable in its crystalline state, but is converted to a quaternary ammonium zwitterion when dissolved in Smectic solvents. On the contrary, the corresponding methyl sulfonate rearranges to the quaternary zwitterion both in the solid state and in Smectic solutions. The X-rays analysis of ASE-d ₂ crystals presented in this paper can explain this different reactivity. ASE-d ₂ crystals belong to the triclinic space group P1. The unit cell contains two independent, centrosymmetric pairs of molecules, stacked in a head-to-tail-like orientation. Intermolecular quaternization of ASE in the solid state is prevented by the distances between the reactive dimethylamino and allyl groups, which are considerably longer than those found in methyl(p-dimethylamino) benzene sulfonate.

Key Words:

• liquid crystalline catalysis
• solid state reactivity