Luminescent 3D homochiral coordination polymers of europium(III) and terbium(III) based on amino acid-functionalized isophthalic acid

Abstract

The use of purely chiral fluorescent tricarboxylic ligand (S)-5-(((1-carboxy-2-phenylethyl)amino)methyl)isophthalic acid (H3L) led to isostructural lanthanide-based homochiral metal-organic frameworks, [EuCl(HL)]n (1) and [TbCl(HL)]n (2), in which every zwitterionic ligand HL connects five metal ions and metal nodes Eu3+ and Tb3+ adopt eight- and seven-coordinated modes, respectively. They are 5-connected novel 3D homochiral coordination polymers consisting of interesting triple-stranded helixes and display the strong characteristic emissions corresponding to Eu3+ and Tb3+. Both 1 and 2 exhibit high thermal stability, which was demonstrated by TGA. In addition, the chiroptical activity of 1 and 2 was also investigated by CD spectra.