Synthesis, Structure, and Ligand-Centered Catalytic Properties of M-II Coordination Polymers (M=Zn-II, Cd-II, Hg-II) with Open Pyridyl N-Oxide Sites

摘要

Four M-II (M=Zn-II, Cd-II, Hg-II) coordination polymers were designed and synthesized based on two pyridine N-oxide bridging ligands: 3,5-bis(4-pyridyl) pyridine N-oxide and 2,6-bis(3-pyridyl) pyridine N-oxide. The resulting polymers all feature a one-dimensional chain motif and contain free pyridyl moieties. More importantly, they exhibit interesting ligand-centered (pyridyl N-oxide) catalytic behavior, and can be used as highly heterogeneous catalysts to promote the Knoevenagel condensation reaction under ambient conditions.