Hollow and microporous catalysts bearing Cr()-F porphyrins for room temperature CO fixation to cyclic carbonates

Hollow and microporous metal free/Cr-porphyrin networks were prepared via the Sonogashira coupling of metal-free or Cr-tetra(4-ethynylphenyl) porphyrins and 1,4-diiodobenzene on the surface of silica templates followed by silica etching. Zinc was introduced into a hollow and microporous metal free porphyrin network (H-MPN) through post-synthetic modification to form a H-MZnPN. Hollow and microporous Cr( iii )-F porphyrin networks (H-MCrPNs) showed the best catalytic activities in room temperature CO 2 fixation with epoxides to cyclic carbonates. In addition, the H-MCrPN could be reused at least for five runs, maintaining the original catalytic activity. The good performance of the H-MCrPN is attributed to its microporosity, the shortened diffusion pathways for substrates due to the hollow structure, and the efficient Lewis acidic activity of Cr( iii )-F moieties. Hollow and microporous Cr( iii )-F porphyrin networks showed excellent catalytic activities in room temperature CO 2 fixation with epoxides to cyclic carbonates due to the hollow structure and the efficient Lewis acidic activity.