Temperature-controlled assembly of homochiral metal-organic frameworks from 2D helical layers to 3D frameworks

Abstract

Two pairs of homochiral metal-organic frameworks (HOMFs), {[Zn((R)-CBA) (1.3- DIB)]·H2O}n(1-D), {[Zn((S)-CBA) (1.3-DIB)]·H2O}n(1-L), [Zn2((R)-CBA)2 (1.3-DIB)2]n (2-D) and [Zn2((S)-CBA)2(1.3-DIB)2]n (2-L), have been synthesized by using lactate derivatives (R)/(S)-H2CBA and N-donor ancillary 1,3-DIB ligands at different reaction temperatures (H2CBA = 4-(1-carboxyethoxy)benzoic acid, 1,3-DIB = 1,3-di(1H-imidazole-1-yl) benzene). Complexes 1-D and 1-L are two-dimensional (2D) layers based on three kinds of chiral helical chains, while complexes 2-D and 2-L are four-connected three-dimensional (3D) frameworks with cds nets. The resulting homochiral complexes have been characterized by PXRD, TGA, IR and CD measurements. Additionally, complexes 1-D and 2-D exhibit different photoluminescence behaviors in solid sate compared to ligand (R)-H2CBA. The work has shown that the dimensionality of HMOFs can be regulated by the reaction temperature.