Molecular and crystalline architectures based on HgI2: from metallamacrocycles to coordination polymers

Abstract

Three metallamacrocycles and one coordination polymer were obtained by using coordination driven self-assembly of the HgI₂ salt with four different ligands: 2,2′-butan-1,4-diylbis(oxy)dianiline (L1), 1,4-bis(2′-formylphenyl)-1,4-dioxabutane bis(isonicotinoylhydrazone) (L2), (E)-N′-(pyridin-3-ylmethylene)isonicotinohydrazide (L3) and (E)-1-(pyridin-3-yl)-N-(pyridin-3-ylmethyl)methanimine (L4). The coordination compounds were studied by elemental analysis, FT-IR spectroscopy and single-crystal X-ray diffraction analyses. Reaction of the HgI₂ salt with L1, L2 and L3 yields metallamacrocycles of formula [(HgI₂)₂(μ-L1)₂] (1), [(HgI₂)₂(μ-L2)₂] (2), [HgI₂(μ-L3)]₄ (3). In contrast, the reaction with L4 under the same conditions yields a coordination polymer of formula [{HgI₂(L4)}]_n (4). In addition, the X-ray structure of L2 is also reported. The influence of the flexibility of the ligand on the final shape and nuclearity of the macrocycle is also analysed. Hirshfeld surface analysis and fingerprint plots facilitate a comparison of intermolecular interactions in all compounds, which are crucial in the construction of the supramolecular architectures. Finally, some noncovalent interactions have been evaluated energetically using DFT calculations and characterized using Bader's theory of atoms-in-molecules.