Metalloporphyrin-based porous organic polymer as an efficient catalyst for cycloaddition of epoxides and CO2

The chemical fixation of carbon dioxide to afford value added chemicals under solvent free and ambient conditions has gained considerable attentions. In this work, we successfully synthesized the porphyrin-based porous organic framework (PPOPs) through Schiff base reaction using 5,10,15,20-tetra(4-aminbiphenyl) porphyrin (TAPP) and 4,4'-biphenyldicarbaldehyde (BDA) as starting materials, which was then coordinated with cobalt to yield related metal complex (Co-PPOPs). The chemical structure and morphology of Co-PPOPs were characterized by absorption spectrum, FT-IR, X-ray photoelectron spectra (XPS), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray powder diffraction (XRD) and nitrogen physisorption. Co-PPOPs showed excellent catalytic activity towards the conversion of carbon dioxide to cyclic carbonates under ambient conditions. Furthermore, Co-PPOPs was recovered easily and could be used repeatedly (more than five times) without losing any catalytic activity. Thus, the as-prepared Co-PPOPs was a promising heterogeneous catalyst for carbon dioxide conversion, providing high turnover number than the previously reported catalysts.