New flexible bis-pyridyltetrazole ligands for use in coordination polymer formation: Synthesis and structural studies

•Three bis-tetrazole ligands containing carboxylate groups were synthesised.•Formation of coordination polymers and metal-organic frameworks.•Polymorphism was exhibited by one of the ligands.

In this work, we have further developed the pyridyl-tetrazole ligand systems into bis-tetrazole systems, where the linker introduced to join these moieties was a flexible (CH2)3 backbone, with the intention of forming frameworks with potential voids. We synthesised three different pyridyl-tetrazoles linked via this flexible backbone through the pyridine ring and not the tetrazole rings. Two crystals of ligand 1 were solved by X-ray crystallography and showed interesting polymorphism. No crystals of the copper(II) complexes of the ligands could be obtained, suggesting that they were polymeric in nature.

Graphical abstractThree novel bis-tetrazole ligands containing carboxylate functional groups on the tetrazole rings and a flexible (CH2)3 linker unit, for the construction of coordination polymers when coordinated to copper(II) ions, were synthesised and structurally characterised. Polymorphism was exhibited by one of the ligands.Figure optionsDownload full-size imageDownload as PowerPoint slide