ZnII coordination polymers constructed with malonate and bipyridyl ligands: Photoluminescence and heterogeneous catalytic reactivity

Abstract Four three-dimensional Zn II frameworks containing malonates and various bipyridyl pillars (4,4′-bipyridine ( 1 ), 1,2-bis(4-pyridyl)ethane ( 2 ), 1,2-bis(4-pyridyl)ethylene ( 3 ) and 1,3-bis(4-pyridyl)propane ( 4 )) have been prepared, and their structures were determined by X-ray crystallography. In all four frameworks, malonate ligands bridge three Zn ions to form two-dimensional layers, and these layers are connected by bipyridyl pillars to form three-dimensional frameworks with the general formula [{Zn(H 2 O)(μ-malonate)} 2 (μ-bipyridyl)] and which also contain water or acetonitrile solvates. Reactivity studies of compounds 1 – 4 showed that they catalyzed a heterogeneous transesterification reaction of phenyl acetate and could be reused without any significant loss of activity through five runs. Emissions were observed at 347–365 nm ( λ ex  = 313 nm) for 2 and 363 nm ( λ ex  = 328 nm) for 3 , while compounds 1 and 4 showed no luminescence properties. The thermal stabilities of these complexes were also examined.