Syntheses, crystal structures and supramolecular assemblies of two Cu(II) complexes based on a new heterocyclic ligand: insights into C-H•••Cl and π•••π interactions

A new heterocyclic ligand, N3L [4-(1-methylimidazole)-2,6-di(pyrazinyl)pyridine] has been synthesized and characterized by several spectroscopic methods. The ligand (N3L) was then used for the preparation of two complexes, namely, [Cu(N3L)Cl-2] (complex 1) and [Cu(N3L)(Cl)(mu-ONO2)](n), (complex 2). The crystal structures of these complexes have been established by single-crystal X-ray diffraction analysis. Complex 1 is a mononuclear one whereas complex 2 is a 1D coordination polymer. The structural insights reveal that non-classical hydrogen bonding (C-H center dot center dot center dot Cl, C-H center dot center dot center dot O, C-H center dot center dot center dot N) and pi center dot center dot center dot pi stacking interactions play a crucial role in stabilizing various supramolecular architectures of the title complexes in the solid state. All the non-classical hydrogen bonding interactions are quantified through the infographic 2D fingerprint plots. Additionally, theoretical calculations (density functional theory) were carried out for both complexes to analyze these non-covalent interactions in the solid state including their characterization using Bader's theory of atoms in molecules and the noncovalent interaction (NCI) plot index.

Automated summary

A new heterocyclic ligand, N3L, has been synthesized and characterized. The ligand was then used to prepare two complexes, and their crystal structures were determined by X-ray diffraction analysis. The study revealed that non-classical hydrogen bonding and π stacking interactions play a crucial role in stabilizing the supramolecular architectures of the complexes in the solid state.