Porous Metalloporphyrinic Frameworks Constructed from Metal 5,10,15,20-Tetrakis(3,5-biscarboxylphenyl)porphyrin for Highly Efficient and Selective Catalytic Oxidation of Alkylbenzenes

We incorporate metal 5,10,15,20-tetrakis(3,5-biscarboxylphenyl)porphyrin (M-H8OCPP), for the first time, into porous metal organic frameworks. The self-assembled porous metalloporphyrinic frameworks [Mn5Cl2(MnCl-OCPP)-(DMF)(4)(H2O)(4)]center dot 2DMF center dot 8CH(3)COOH center dot 14H(2)O (ZJU-18; ZJU = Zhejiang University), [Mn5Cl2(Ni-OCPP)(H2O)(8)]center dot 7DMF center dot 6CH(3)COOH center dot 11H(2)O (ZJU-19), and [Cd5Cl2(MnCl-OCPP)-(H2O)(6)]center dot 13DMF center dot 2CH(3)COOH center dot 9H(2)O (ZJU-20) are isostructural as revealed by their single X-ray crystal structures. The metalloporphyrin octacarboxylates (M-OCPP) (M = (MnCl)-Cl-III for ZJU-18 and ZJU-20, M = Ni-II for ZJU-19) are bridged by binuclear and trinuclear metal carboxylate secondary building units to form a 3-periodic, binodal, edge-transitive net with Reticular Chemistry Structure Resource symbol tbo with pore windows of about 11.5 angstrom and pore cages about 21.3 angstrom in diameter. The porous nature of these metalloporphyrinic frameworks is further established by sorption studies in which different substrates such as ethanol, acetonitrile, acetone, cyclohexane, benzene, toluene, ethylbenzene, and acetophenone can readily have access to the pores. Their catalytic activities for the oxidation of alkylbenzenes were examined at 65 degrees C using tert-butyl hydroperoxide as the oxidant. The results indicate that ZJU-18 is much superior to ZJU-19, ZJU-20, and homogeneous molecular MnCl-Me8OCPP, exhibiting highly efficient and selective oxidation of ethylbenzene to acetophenone in quantitative >99% yield and a turnover number of 8076 after 48 h.