Homochiral Coordination Polymers Based on Amino Acid-Functionalized Isophthalic Acid: Synthesis, Structure Determination, and Optical Properties

Abstract

Three interesting homochiral metal–organic frameworks (HMOFs), namely, [Zn8(L)4(OH)4(H2O)2]n (1), {[Cd2(HL)2(H2O)4]·6H2O}n (2), and {[Pb2(HL)2]·CH3OH·2.5H2O}n (3), have been hydro/solvothermally synthesized through the reaction of the designed chiral ligand (S)-5-(((1-carboxyethyl)amino)methyl)isophthalic acid (H3L) with corresponding metal sources. Crystallographic analysis indicates that the triply deprotonated H3L ligands can adopt anionic (L)3– and zwitterionic (HL)2– forms, various coordination modes, and versatile hydrogen-bonding connections to construct interesting HMOFs with unique architectures. Complexes 1 and 2 are two-dimensional (2D) coordination polymers, but their structural motifs are very different. In 1, anionic (L)3– ligands bridge tetrametallic Zn-clusters to form a 2D layer with (3,6)-connected kgd net. In 2, zwitterionic (HL)2– ligands link CdII ions to generate two types of independent wave-like layers of 63 topology, and the two independent layers are further connected to form the...