Two-dimensional Zn(II) coordination polymer and hydrogen bond-mediated two-dimensional Cu(II) network based on trans-2-aminocyclopentanecarboxylate

Coordination polymers from alpha-amino acids are promising organic-inorganic hybrid composites with chirality and biocompatibility. However, coordination polymers from unnatural amino acids are rarely studied. Here, we report the transition metal complexes from an unnatural beta-amino acid, (1S,2S)-2-aminocyclopentanecarboxylic acid, affording two possible coordination modes from the conformationally rigid cyclopentane ring. X-ray crystallographic analysis revealed that Zn(II) formed a two-dimensional (2D) coordination polymer via N,O-bridging mode. In contrast, Cu(II) formed a discrete complex via N,O-chelating mode and then constructed a 2D supramolecular network stabilized by hydrogen bonding between water and the ligands.