Zinc(II) and Copper(II) Metal-Organic Frameworks Constructed from a Terphenyl-4,4′′-dicarboxylic Acid Derivative: Synthesis, Structure, and Catalytic Application in the Cyanosilylation of Aldehydes
文摘
Solvothermal reaction of zinc(II) and copper(II) salts with 3,3′′-dipropoxy-[1,1′:4′,1′′-terphenyl]-4,4′′-dicarboxylic acid (H2L) gave rise to the 1D and 2D metal–organic frameworks (MOFs) [Zn(L)(dmf)2]m>nm> (1), [Zn2(L)(NO3)2(4,4′-bipyridine)2]m>nm>·m>nm>(DMF) (2), [Cu(L)(H2O)2]m>nm>·2m>nm>(H2O) (3), and [Cu3(OH)2(L)2]m>nm>·m>nm>(H2O) (4), which were characterized by elemental analysis, FTIR spectroscopy, and X-ray single-crystal diffraction. MOFs 1 and 3 have zigzag- and linear-type 1D structures, respectively, whereas 2 and 4 possess rectangular grid- and layer-type 2D structures. In 2 and in 4, a dinuclear ZnII cluster (C2O4Zn2) and a trinuclear µ3-hydroxo-bridged CuII cluster [Cu3(OH)2]m>nm>, respectively, act as building block units. These frameworks act as heterogeneous catalysts (the Zn-MOFs are more active than Cu-MOFs, and 1 is the most efficient) for the cyanosilylation of aldehydes with trimethylsilyl cyanide at room temperature. These MOF-based heterogeneous catalysts can be easily recovered and reused, at least over a few consecutive cycles, without losing activity.