0D and 1D copper(II) coordination polymers based on 2-methyl-1H-imidazole: Structural, vibrational and magnetic characterizations

• Two new hybrid materials were prepared from Copper(II) chloride dehydrate, Hydrochloric acid and 2-methyl-1H-imidazole.
• The two compounds, monomer 1 and polymer 2, are formed in an obviously pH-dependent manner.
• The synthesized materials have a supramolecular and lamellar aspects supported by multiple intermolecular hydrogen bonding.

Bis(2-methyl-1H-imidazolium)tetrachlorocuprate(II), monomer 1, and 2-methyl-1H-imidazoliumaquatrichlorocuprate(II), polymer 2, were synthesized and their crystal structures were determined. N/C–H⋯Cl hydrogen bonds stabilize the monomeric structure of the tetrachlorocuprate(II) anion together with the steric demand of the relatively large 2-methylimidazolium ions in the crystal lattice of 1. Conversely, in 2, O–H⋯Cl hydrogen bonds reduce the electron density on the chloride ions in such a way the electron repulsions decrease and coordination spheres with more ligands develop. Obviously, water may be a successful competitor for ligand sites in 2 as well. In 2, The square-pyramidal structural parts [CuCl3(H2O)]− condense into polymeric chains of –CuCl2(H2O)-μ-Cl–CuCl2(H2O)-μ-Cl–CuCl2(H2O)–. In both complexes, aromatic amines linked through π⋯π interactions, are intercalated between the inorganic layers to provide a new structure topology that gathers between supramolecular and lamellar aspects. Magnetic measurements indicate the presence of weak antiferromagnetic interactions in compound 2.

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