Reversible Self-Assembly/Regulation of pH-Responsive Poly(ester-palladium) to Create New Catalytic Nanoreactors for Efficient Reduction of Nitrophenol

The demand for more efficient catalysts has motivated chemists to develop versatile macromolecular catalytic architectures based on the design principles of enzymes. Inspired by metalloenzymes, we have developed the first polyester-supported Pd nanoparticles with molecular precision, where the polymersome offers controllability in terms of size and shape via reversible pH-regulated self-assembly. The variation of pH also leads to the metal coordination sites switching from ester to carboxyl groups, and enables a facile separation of catalysts from the system. Tested for 4-nitrophenol reduction, this catalytic nanoreactor demonstrated extremely high efficiency even at the parts per million level of PdNPs. This work provides insights into the switchable metal–organic coordination in both artificial and biological catalytic systems and the strategy to develop bioinspired catalysts with high efficiency and precisely tuned physical properties.