Three new zinc(II) 4′-chloro-2,2′:6′,2ʺ-terpyridine (4′-Cltpy)-based complexes: synthesis, spectroscopic and structural studies, thermal behavior, and Hirshfeld surface analysis

Abstract

Three new Zn^II complexes with the ligand 4′-chloro-2,2′:6′,2ʺ-terpyridine (4′-Cltpy), [Zn(4′-Cltpy)(N₃)₂] (1), [Zn(4′-Cltpy)(NCS)₂] (2) (two 1:1 metal/ligand complexes) and a 1:2 metal/ligand complex, [Zn(4′-Cltpy)₂](NO₃)₂·2H₂O (3), have been synthesized and characterized by elemental analysis, IR, ¹H NMR spectroscopy and single-crystal X-ray diffraction. The structures of 1 and 2 contain a ZnN₅ coordination sphere, which includes coordination from three nitrogen donors of the 4′-Cltpy ligand and two nitrogen atoms of two terminal azide or two terminal thiocyanate ligands, respectively. Addison’s τ value suggests a distorted square pyramidal coordination of Zn^II in 1 and intermediate between square pyramidal and trigonal bipyramidal in 2. In the complex cation of 3, the Zn^II center is coordinated by six nitrogen atoms from two 4′-Cltpy ligands in a distorted octahedral coordination geometry. In this structure, two non-coordinating nitrate anions serve as counterions, and there are two non-coordinating solvent water molecules. Hirshfeld surface analysis was employed to clarify the nature and extent of intermolecular interactions. In addition, the thermal stabilities of the compounds were evaluated by thermogravimetric analysis (TGA).

Graphical abstract

Keywords:

• Zinc(II)
• 4′-Chloro-2,2′:6′, 2ʺ-terpyridine
• crystal structure
• Hirshfeld surface analysis
• thermal stability

Acknowledgements

The authors are grateful to the Urmia University for financial support of this study.

Declaration of competing interest

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.