Syntheses, structures and properties of chiral Ln(III) coordination polymers based on (R)-4-(4-(1-carboxyethoxy)phenoxy)-3-fluorobenzoic acid

Abstract

Two isomorphic chiral lanthanide coordination polymers (CCPs), namely, [Ln2(cpfa)3]n {Ln=Yb Xu et al. (2011) and Lu Zheng et al. (2015) } {H2cpfa=(R)-4-(4-(1-carboxyethoxy)phenoxy)-3-fluorobenzoic acid, have been synthesized under hydro(solvo)thermal conditions. Their structures have been determined by single-crystal X-ray diffraction analyses and further characterized by infrared spectra (IR), powder X-ray diffraction (PXRD), elemental analyses, thermogravimetric (TG) analyses and circular dichroism spectra (CD). Structure analysis reveals that CCPs 1 and 2 are isomorphic, crystallizing in Orthorhombic space group P212121 and giving 3D rhombic framework. Further, CCP 1 show the strong NIR luminescence of Yb(III) ions, suggesting that [cpfa]2− is able to sensitize the luminescence of lanthanide ions efficiently. The two polymers also exhibit modest SHG efficiency indicating their potential application as optical materials. Thermogravimetric analyses show the remarkable thermal stabilities of the two lanthanide 3D frameworks up to 420°C.