Visible Light-Driven Suzuki-Miyaura Reactions by Self-Supported Pd Nanocatalysts in the Formation of Stille Coupling-Based Photoactive Microporous Organic Polymers

Stille coupling was applied to synthesize microporous organic polymers (MOPs). Metallic Pd was in situ self-supported during the networking of 1,3,6,8-tetrabromopyrene with 1,4-bis(tributylstannyl)benzene to form Stille coupling-based MOP(St-MOP)@Pd. The size of St-MOP particles and the amount of metallic Pd in the St-MOP@Pd depended on the amount of a Pd catalyst. As the amount of a Pd catalyst increased, the size of St-MOP particles decreased with an increase of metallic Pd, due to the increased St-MOP nuclei in the early growth stage of St-MOP. The St-MOP bearing pyrenes showed absorption and emission of visible light and the St-MOP@Pd showed excellent catalytic performance in the visible light-driven Suzuki-Miyaura coupling. The optimal St-MOP@Pd-2 (0.14 mol% Pd) showed a TON of 657 and a TOF of 219 h-1 in the visible light-driven Suzuki-Miyaura coupling of 1-acetyl-4-bromobenzene and phenyl boronic acid at 25oC. The optimal amount of St-MOP and metallic Pd in the St-MOP@Pd was critical to achieve excellent catalytic performance. The overall photocatalytic principles of St-MOP@Pd were rationalized by computational simulation.