Cooperative catalysis of Cu/2,2,6,6-tetramethyl-1-piperidine- N -oxyl nanocatalysts supported by ultraviolet light-responsive polyimides.

The development of ultraviolet (UV) light-regulated cooperative catalysts has attracted wide attention and increased the understanding of structure-activity relationships. Here, we have used azobenzene-containing polyimides as supports for the controllable synthesis of Cu/2,2,6,6-tetramethyl-1-piperidine- N -oxyl (TEMPO) nanocatalysts. Of these nanocatalysts, the catalytic components bearing a pyrene moiety were immobilized onto polyimides containing azobenzene and naphthalene diimide (NDI) moieties via aromatic stacking interactions and hydrophobic interactions in nanoprecipitation. Aromatic stacking clusters were formed and randomly distributed inside nanocatalysts, bringing catalytic components in close proximity for cooperative catalysis. The size of aromatic stacking clusters might be regulated by the UV light-responsive azobenzene units of polyimides. This strategy may find applications in the design and engineering of other multifunctional heterogeneous catalysts with controllable UV light-responsive behaviors.