Construction of two mixed-ligand coordination polymers presenting unusual polyrotaxane-like entanglements

Two novel polyrotaxane-like coordination polymers, [Ni4(L)4(H2O)3(bpp)4]·3H2O (1) and [Cd4(L)4(bpp)3]·3H2O (2) (H2L=Me2Si(p-C6H4COOH)2, bpp=1,3-bis(4-pyridyl)propane), have been synthesized and structurally characterized. Compound 1 features a 2D→3D polyrotaxane array by the interlock of bilayer networks. Compound 2 exhibits an unusual 3D polyrotaxane-like self-threading framework. In addition, compound 2 shows an emission at 485nm when it was excitated at 400nm.