²⁹Si Solid-State NMR Spectroscopy of Guanine-Modified Rice Husk Silica (RHACGua)

Abstract

This study details the characterisation of an organic-inorganic hybrid catalyst named RHACGua, using Solid-state NMR Spectroscopy. The catalyst was developed by incorporating guanine onto silica derived from rice husk ash (RHA), with (3-chloropropyl) triethoxysilane (CPTES) used as an anchoring agent to facilitate the binding of guanine to the silica. Characterisation of RHACGua was conducted through nitrogen sorption analysis and solid-state nuclear magnetic resonance (NMR) spectroscopy for ²⁹Si. The ²⁹Si solid-state NMR spectra revealed distinct silicon environments (Q⁴, Q³, T³, T²) in RHACGua, indicating successful modification of the Cl functional group with guanine. These results confirm the successful synthesis of the RHACGua catalyst through the modification of RHACCl with guanine, demonstrating its potential for applications in heterogeneous catalysis.