Chiral silicate zeolites

Chiral zeolites are porous materials of prime importance because of their enantioselective potential applications in catalysis, in separation-science and in chromatography. We report a surprising observation made: as many as many 20 chiral silicate zeolites, none of which were recognized as such in their original publication, exist. In other words, the "holy grail'' of having a library of such silicates was right under our nose. To be of practical use, such zeolites must reveal molecular level enantioselectivity; we show, for the first time, that chiral silicate zeolites are capable of enantioselective recognition of enantiomers, as revealed from comparative adsorption calorimetry experiments with either D- or L-histidine. The question of how to assign handedness to a chiral zeolite is addressed.