Two complexes of copper (II) and cobalt (II) with N,O-chelating heterocyclic carboxylates: Crystal structures, Hirshfeld surfaces, and thermal properties

ABSTRACT

Two complexes 1 [Cu( L₁ )₂(H₂O)₂]·2H₂O and 2 [Co( L₂ )₂ (H₂O)₄]·4H₂O formed by hetero N- and O-donor ligands 1-methyl-3-imidazole-4-carboxylic acid ( L₁ H) and 2-methyl-5-pyridine carboxylic acid ( L ₂ H) have been synthesized and characterized by elemental analysis and single-crystal X-ray diffraction. These two complexes consist of a 2:1 ratio of ligand to metal ion. The analysis of Hirshfeld surfaces and crystal structures reveal that O‒H···O hydrogen bond interactions and C‒H···π intermolecular interactions support the three-dimensional supramolecular structures of complexes 1 and 2. Meanwhile, the coordinated water molecules and lattice water molecules play a key role in the construction of their crystal structures.

KEYWORDS:

• Coordinated water
• crystal structure
• hetero ligands
• intermolecular interaction

Funding

This work has been supported by National Natural Science Foundation of China (21371031) and International S&T Cooperation program of China (2015DFG42240).