Metalated Mesoporous Poly(triphenylphosphine) with Azo Functionality: Efficient Catalysts for CO₂ Conversion

Mesoporous poly(triphenylphosphine) with azo functionality ( poly(PPh 3 )-azo ) is reported, which was synthesized via oxidative polymerization of P( m -NH 2 Ph) 3 at ambient conditions. This kind of polymer could strongly coordinate with metal ions (e.g., Ru 3+ ) and could reduce Ag + in situ to metallic form. The resultant metalated poly(PPh 3 )-azo (e.g., poly(PPh 3 ) -azo-Ag or -Ru ) were discovered to be highly efficient catalysts for CO 2 transformation. Poly(PPh 3 )-azo-Ag showed more than 400 times higher site-time-yield (STY) for the carboxylative cyclization of propargylic alcohols with CO 2 at room temperature compared with the best heterogeneous catalyst reported. Poly(PPh 3 )-azo-Ru also exhibited good activity for the methylation of amines with CO 2 . It was demonstrated that the high performances of the catalysts originated from the cooperative effects between the polymer and the metal species. In addition, both catalysts showed good stability and easy recyclability, thus demonstrating promising potential for practical utilization for the conversion of CO 2 into value-added chemicals.