Crystal structure and Hirshfeld surface analysis of mono/bis-(aqua-κ O)[ N-(2-oxido-benzyl-idene)valinato-κ3 O, N, O']copper(II): dimeric Schiff base copper(II) complexes having different numbers of coordinated water mol-ecules

Abstract

The mol-ecular structure of the title compound, [Cu(C₁₂H₁₃N₂O₃)(H₂O)₂]·[Cu(C₁₂H₁₃N₂O₃)(H₂O)], consists of two different mol-ecules in the asymmetric unit. Both of the structures consist of a tridentate ligand synthesized from l-valine and salicyl-aldehyde, and one water mol-ecule or two water mol-ecules coordinating to Cu^II. They have a square-planar (mol-ecule 1) or a square-pyramidal (mol-ecule 2) coordination geometry. In the crystal, the mol-ecules form intra- and inter-molecular O-H⋯O hydrogen bonds involving the coordinated water mol-ecules and other sites. A Hirshfeld surface analysis indicated that the most important contributions to the packing are from H⋯H [52.9% (mol-ecule 1) and 51.1% (mol-ecule 2)] and H⋯O/ O⋯H [21.2% (mol-ecule 1) and 25.8% (mol-ecule 2)] contacts. In addition, an electrostatic potential map was also obtained from DFT calculations to support the discussion of the inter-molecular inter-actions.

Keywords: Hirshfeld analysis; Schiff base complex; amino acid; copper; crystal structure.