Chiral and achiral 1D copper(ii) coordination polymers based on glycolato and chelating aromatic diamine ligands

Abstract

Achiral glycolic acid and chelating aromatic diamine ligands were employed at room temperature to prepare five 1D copper(II) coordination polymers which were structurally characterized. The polymers _∞¹{[Cu(HG)(dipyam)](HG)} (1) (dipyam = 2,2′-dipyridylamine) and _∞¹[Cu(HG)(ClO₄)(NN)] (NN = 2,2′-bipyridine (2), NN = 1,10-phenanthroline (3)) adopt homochiral helical structures in the crystal state and undergo spontaneous chiral resolution in the solid state. On the other hand, the polymers containing bidepronated glycolato ligand G, _∞¹{[Cu(G)(dipyam)]·H₂O} (1a), obtained from a solution of 1 in MeOH/ⁱPrOH and _∞¹{[Cu₂(μ-G)(ClO₄)(H₂O)(dipyam)₂](ClO₄)(H₂O)₂} (4b) are achirals. Crystals of 4b have been obtained together with crystals of the molecular complex [Cu(HG)(H₂O)(dipyam)](ClO₄) (4a). Analysis by Hirshfeld surface generation and two-dimensional fingerprinting was carried out to study the nature of the interactions and their contributions towards the crystal packing.