Molecular and supramolecular properties of a Hg(II) complex with (E)-N,N′-bis(2-pyridyl)iminoisoindoline: synthesis, spectroscopy, X-ray structure and Hirshfeld surface analyses, and DFT calculations

Abstract

A scarcity of metal complexes containing (E)-N,N′-bis(heteroaryl)iminoisoindolines has prompted us to investigate the coordinating ability and supramolecular behavior of (E)-N,N′-bis(2-pyridyl)iminoisoindoline (2-pyimiso), a versatile iminobis(pyridyl) ligand. The 1:1 reaction of HgCl₂ with 2-pyimiso in MeOH afforded a dinuclear complex, [{HgCl(2-pyimiso)}₂(μ-Cl)₂] (1). The complex has been characterized by elemental microanalysis, vibrational spectroscopy (FTIR and FT-Raman) and ¹H NMR spectroscopy. DFT calculations at the B3LYP-D3/LACV3P** level have been used in support of our vibrational analysis. Single-crystal X-ray diffraction data have shown that the coordination geometry of 1 is intermediate between the trigonal pyramidal and seesaw shapes insofar as each Hg(II) is four-coordinate and 2-pyimiso is a monodentate ligand. X-ray structure and Hirshfeld surface analyses have revealed that the supramolecular arrangement of 1 comprises perpendicular 1-D chains along the [011] direction assembled by nonclassical C–H⋯Cl–Hg and C–H⋯π hydrogen bonds. Moreover, adjacent sheets parallel to the bc-plane are interconnected by C–H⋯N_py, π–π_py stacking, and Hg⋯π_py interactions.

Keywords:

• Mercury
• N ligands
• structure elucidation
• supramolecular chemistry
• DFT calculations

Acknowledgments

The authors are grateful to the Brazilian funding agencies Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES), Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq), Fundação Carlos Chagas Filho de Amparo à Pesquisa do Estado do Rio de Janeiro (FAPERJ) and Fundação Universitária José Bonifácio (FUJB) for sponsorship, and to Prof. J.G.S. Lopes (Universidade Federal de Juiz de Fora, Brazil) for the FT-Raman spectrum of 1.