A highly robust {ZnTb}n-Organic framework for excellent catalytic performance on cycloaddition reaction of epoxides with CO2

Effective chemical fixation of CO2 into high value-added industrial raw materials, recognized as an effective strategy to alleviate energy crisis and environmental pollution, makes the research of innovative catalysts a hot topic. Herein, a robust {ZnTb}n-chain-based framework of {[ZnTb(CPPDP)(H2O)]·5DMF·H2O}n (NUC-62) achieved from the solvothermal condition was reported. In NUC-62, nanoporous channels (aperture ca. 10.5 Å) are shaped by six rows of {ZnTb(CO2)5(H2O)}n chains, which is the first reported 3d-4f heterometallic chain with the staggered arrangement of Zn2+ and Tb3+. As for the activated NUC-62a with the removal of lattice and coordinated DMF and H2O, the host framework characterizes the merits of exposed Lewis-acidic metal sites, high specific surface, large void volume and stable chemical property. Furthermore, NUC-62a was tested as a heterogenous catalyst for the two organic reactions of cycloaddition of CO2 with epoxides and Knoevenagel condensation of aldehydes and malononitrile, in which NUC-62a display the high catalytic performance along with high selectivity and excellent recyclability. Hence, this work provides an effective synthesis strategy for MOFs-based catalysts.