Porous polymeric metalloporphyrin obtained through Sonogashira coupling: Catalytic performance at CO2 cycloaddition to epoxides

Abstract

Using metal complexes of (5,10,15,20-tetrakis(p-bromophenyl) porphyrin) (MT4BrPP) (M ​= ​Co, Mn) and 4,4-diethynylbiphenyl as monomers, a porous polymeric metalloporphyrin [PoP(MTPP), M ​= ​Co, Mn] was successfully synthesized by Sonogashira cross-coupling reaction. Their morphology, structure and elements were characterized and analyzed by scanning electron microscopy (SEM), Fourier-Transform infrared spectroscopy (FT-IR), X-ray photoelectron spectra (XPS), thermogravimetric analysis (TG), and brunauer-emmett-teller (BET), which indicated high specific surface area and good thermal stability. Then, using PoP(MTPP) as porous catalyst with two-dimensional structure, the cycloaddition reaction of epoxides and carbon dioxide (CO2), for reducing greenhouse gas emissions, was effectively executed without solvents, and the yield of cyclocarbonate got to 90%. In summary, a novel metalloporphyrin based porous polymers were prepared by coupling reaction, and catalytic active centers were effectively fixed in two-dimensional networks, which improved its stability and excellently enhanced their catalytic performance. It’s a competitively candidates for catalyzing the cycloaddition reaction without solvent.