Designed heterogeneous palladium catalysts for reversible light-controlled bioorthogonal catalysis in living cells.

As a powerful tool for chemical biology, bioorthogonal chemistry broadens the ways to explore the mystery of life. In this field, transition metal catalysts (TMCs) have received much attention because TMCs can rapidly catalyze chemical transformations that cannot be accomplished by bio-enzymes. However, fine controlling chemical reactions in living systems like bio-enzymes is still a great challenge. Herein, we construct a versatile light-controlled bioorthogonal catalyst by modifying macroporous silica-Pd0 with supramolecular complex of azobenzene (Azo) and β-cyclodextrin (CD). Its catalytic activity can be regulated by light-induced structural changes, mimicking allosteric regulation mechanism of bio-enzymes. The light-gated heterogeneous TMCs are important for in situ controlling bioorthogonal reactions and have been successfully used to synthesize a fluorescent probe for cell imaging and mitochondria-specific targeting agent by Suzuki-Miyaura cross-coupling reaction. Endowing the bioorthogonal catalyst with new functions is highly valuable for realizing more complex researches in biochemistry.