Immobilization of a Zn4 complex on functionalized layered HUS-7: synthesis, structural investigation and catalytic activity.

A tetranuclear Zn (Zn₄) complex was selected for immobilization on novel layered Hiroshima -University Silicate (HUS)-7. Modification of HUS-7 was carried out using a sulfopropylsilyl agent followed by Zn₄ complex incorporation. The structural investigation of this organic-inorganic, hybrid layered HUS-7 material was performed using various measurements to confirm the tethering of guest molecules. The modified HUS-7 was used as a catalyst for two different catalytic epoxide ring opening reactions, yielding two different regioisomeric products (b-amino alcohols). Theoretical energy calculations were performed for the pure Zn₄ complex, substrate, nucleophile, intermediates and products to check the stability of the regioisomer for the morpholine system. The catalyst was found to be highly active for both the reaction systems with reusability up to the fourth cycle supporting the significance of the proposed functionalization. Furthermore, investigation of structural changes of the spent catalyst was also carried out. [ABSTRACT FROM AUTHOR]