A zeolite family with chiral and achiral structures built from the same building layer

Abstract

Porosity and chirality are two of the most important properties for materials in the chemical and pharmaceutical industry. Inorganic microporous materials such as zeolites have been widely used in ion-exchange, selective sorption/separation and catalytic processes. The pore size and shape in zeolites play important roles for specific applications. Chiral inorganic microporous materials are particularly desirable with respect to their possible use in enantioselective sorption, separation and catalysis. At present, among the 179 zeolite framework types reported, only three exhibit chiral frameworks. Synthesizing enantiopure, porous tetrahedral framework structures represents a great challenge for chemists. Here, we report the silicogermanates SU-32 (polymorph A), SU-15 (polymorph B) (SU, Stockholm University) and a hypothetical polymorph C, all built by different stacking of a novel building layer. Whereas polymorphs B and C are achiral, each crystal of polymorph A exhibits only one hand and has an intrinsically chiral zeolite structure. SU-15 and SU-32 are thermally stable on calcination.