The design of novel heterogeneous catalysts with multiple adjacent functionalities is of high interest for heterogeneous catalysis. Herein, we report a method to obtain a majority bifunctional acid-base pairs on SBA15. Aniline reacts with SBA15 by opening siloxane bridges leading to N-phenylsilanamine-silanol pairs. In contrast with ammonia treated surfaces, the material is stable under air/moisture. Advanced solid state MAS NMR: 2D ¹H-¹H double-quantum, ¹H-¹³C HETCOR experiments and dynamic nuclear polarization enhanced ²⁹Si and ¹⁵N spectra demonstrate both the close proximity between the two moieties and the formation of a covalent Si-N surface bond and confirm the design of vicinal acid-base pairs. This approach was successfully applied to the design of a series of aniline derivatives bifunctional SBA15. A correlation of the substituents effects on the aromatic ring (Hammet parameters) on the kinetics of the model reaction of Knoevenagel is observed.
Bibliographical noteKAUST Repository Item: Exported on 2020-10-01
Acknowledged KAUST grant number(s): CRG_R2_13_BASS_KAUST_1
Acknowledgements: This work received support from the King Abdullah University
of Science and Technology (KAUST) Office of Sponsored
Research (OSR) under Award No CRG_R2_13_BASS_KAUST_1.
We thank Dr. Olivier Ouari and Paul Tordo for providing the