Zirconium(IV)-modified silica gel: Preparation, characterization and catalytic activity in the synthesis of some biologically important molecules

Abstract

Zirconium modified silica gel was prepared by the grafting method and the resulting organic–inorganic hybrid material was found to be a highly effective catalyst for the range of organic transformations such as syntheses of coumarins, quinoxalines and 2,4,5-trisubstituted imidazoles. The low percentage of zirconium in the catalyst gave products in high turnover numbers; the catalyst was recovered after reaction, and reused. The structure of the catalyst was investigated and confirmed by surface area (BET), FT-IR, ED-XRF and elemental analyses, 13C-CPMAS spectral studies, molecular mechanics studies and inductively coupled plasma mass spectrometry technique (ICP-MS).