Incorporation of Metals and Enzymes with Porous Imine Molecule Cages for Highly Efficient Semiheterogeneous Chemoenzymatic Catalysis
Shiqi Gao, Yunting Liu, Lihui Wang, Zihan Wang, Pengbo Liu, Jing Gao, Yanjun Jiang
Abstract
Combining the advantages of homogeneous and heterogeneous catalysis is highly desired but remains a challenging goal. Herein, we fabricated a semiheterogeneous metal–enzyme-integrated catalyst using soluble porous imine molecule cages (IMCs), which could partially dissolve in organic solvents under heating conditions for catalytic tasks while precipitate completely at room temperature for catalyst recovery. The IMCs play three vital roles: (1) acting as a support and stabilizer for metal nanoparticles and enzymes, (2) partially solubilizing the heterogeneous catalyst in organic medium, and (3) creating hydrophobic and basic microenvironments for improved catalytic efficiency. The covalent immobilization of the enzyme by utilizing imine bonds via the Ugi-type reaction was disclosed, in which the effect of different parameters on enzyme immobilization and the structure–activity relationship were investigated. The semiheterogeneous catalyst exhibited high activity, selectivity, and reusability in chemoenzymatic dynamic kinetic resolution of amines at low temperature (50–60 °C) with high yields and enantioselectivities (up to 94% yield and 98% ee).