Structural assemblies of four Cd(II) coordination polymers based on 5-methylisophthalic acid

Abstract

Four new metal-organic coordination polymers, Cd(mip)(DMF)(1), Cd(mip)(EtOH)(2), Cd2(mip)2(H2O)5·3H2O (3), Cd(mip)(bpp)(H2O)·H2O (4) (H2mip = 5-methylisophthalic acid, bpp = 1,3-di(4-pyridyl)propane) have been hydro(solvo)thermally synthesized and characterized by IR, thermogravimetric (TG) analysis, powder X-ray diffraction and single-crystal X-ray diffraction. 1 and 2 are isostructural, and two adjacent Cd centers are bridged by four carboxylate groups in μ2-carboxylato-κ1O.:κ1O′ and μ2Ο; κ2O,O′ fashion to form a linear (Cd–O–Cd)n chain. The adjacent (Cd–O–Cd)n chains are further connected by mip bridges to form a 3D framework. 3 features two types of chiral layers: One left-handed and another right-handed, which lead to racemic solid-state compound. 4 exhibits a two-dimensional wave-like (2D) (4,4) layer structure with infinite 1D linear chain. In addition, the luminescent properties of 1–4 are also discussed.