FOOTPRINT CATALYSIS .7. REINVESTIGATION OF THE IMPRINTING PROCEDURES FOR MOLECULAR FOOTPRINT CATALYTIC CAVITIES - THE EFFECTS OF IMPRINTING PROCEDURE TEMPERATURE ON THE CATALYTIC CHARACTERISTICS

The authors' imprinting procedures for ''molecular footprint'' catalytic cavities on a silica (alumina) gel surface were reinvestigated. The increases of temperature during the incorporation of aluminum ions into the silicate matrix and during the footprint-imprinting with a template remarkably affected the catalytic characteristics of the resulting cavities. A change from room temperature to 75-80-degrees-C increased the catalytic specificities (k(cat)/K(m)) by a factor of nearly 50. The results also provided experimental proof for the speculated mechanism of footprint formation. That is, the imprinting comprises precedent Lewis acid site generation on a silicate and subsequent Lewis acid-template complexation. The resulting acid-template complexes give rise to the footprint cavities upon removal of the template.