Zirconium coordination polymers based on tartaric and malic acids as catalysts for cyanosilylation reactions

The synthesis of chiral materials is a great challenge. This work describes the synthesis of Zr-based coordination polymers composed of chiral ligands derived from natural products. L-tartaric acid, dibenzoyl-L-tartaric acid and L-malic acid were selected as ligands from the chiral pool. Their reaction with zirconium oxychloride gave rise to several materials that were characterized by different techniques, such as XRD, Raman spectroscopy, 13C MAS NMR, TGA and N2 adsorption/desorption isotherms. Significant structural and textural properties have been observed depending on the ligand, the synthesis procedure and the metal to ligand ratio. These polymers were used for the first time as catalysts in the cyanosilylation of benzaldehyde with trimethylsilyl cyanide and their activity was compared with that of UiO-66. Different reaction parameters and reusability were studied for this asymmetric reaction. Some of the reported materials were very active in this reaction and provided a remarkable enantioselectivity depending on the reaction conditions.