Pd(II)-immobilized on a novel covalent imine framework (COF-BASU1) as an efficient catalyst for asymmetric Suzuki coupling

Abstract

This study reports the synthesis of a new imine-based covalent organic framework (COF) stabilizer through the reaction between 1,4-phenylenediamine and 4,4′,4″-(benzene-1,3,5-triyltris(oxy))tribenzaldehyde (COF-BASU1). Next, palladium (Pd) species were decorated on the synthesized COF, and the obtained Pd/COF-BASU1 composite was used as a heterogeneous catalyst in the asymmetric Suzuki-Miyaura coupling (SMC) reaction. The easily prepared imine-linked COF-BASU1 possesses a two-dimensional eclipsed layered-sheet structure, making its incorporation with metal ions feasible. Via a simple post-treatment, a Pd(II)-containing COF, Pd/COF-BASU1, was accordingly synthesized, which showed excellent catalytic activity in catalyzing the asymmetric Suzuki-Miyaura coupling reaction with high stereoselectivity. The eclipsed imine structure provide chiral environment to achieve the asymmetric Suzuki-Miyaura coupling reactionplay. Afterward, the chiral high-performance liquid chromatography (HPLC) was conducted to examine the axially chiral products generated through these reactions. These products were separated via the HPLC method. This technique is based on the function of some columns whose packing groups can segregate chiral products. The fabricated nanocatalyst was structurally authenticated using various analytical techniques such as FT-IR, XRD, FE-SEM, TGA, EDS, ICP-AES, and BET. The outcomes indicated that Pd/COF-BASU1 nanocomposite is a suitable catalyst to synthesis axially chiral biaryl derivatives with high stereoselectivity (up to 85.37% ee).