Catalytic performance of Zr-based metal-organic frameworks Zr-abtc and MIP-200 in selective oxidations with H2O2.

Catalytic performance of Zr-abtc and MIP-200 metal-organic frameworks consisted of 8-connected Zr 6 -clusters and tetratopic linkers was investigated in H 2 O 2 -based selective oxidations and compared with that of 12-coordinated UiO-66 and UiO-67. Zr-abtc demonstrated advantages in both substrate conversion and product selectivity for epoxidation of electron-deficient C=C bonds in α,β-unsaturated ketones. A significant predomination of 1,2-epoxide in carvone epoxidation, coupled to high sulfone selectivity in thioether oxidation, points to a nucleophilic oxidation mechanism over Zr-abtc. The superior catalytic performance in the epoxidation of unsaturated ketones correlates with a larger amount of weak basic sites in Zr-abtc. Electrophilic activation of H 2 O 2 can also be realized, as evidenced by high activity of Zr-abtc in epoxidation of electron-rich C=C bond in caryophyllene. XRD and FTIR studies confirmed the retention of the Zr-abtc structure after the catalysis. Low activity of MIP-200 in H 2 O 2 -based oxidations is most likely related to its specific hydrophilicity, which disfavors adsorption of organic substrates and H 2 O 2 .