Synthesis and spectroscopic properties of new bis-tetrazoles

Syntheses of N,N′-phenyltetrazole podands link with aliphatic chains containing oxygen, nitrogen and sulphur atoms, are described. The complexing properties of these compounds towards metal cations (Fe(2+), Cu(2+), Zn(2+), Co(2+), Ni(2+)) were investigated by absorption and infrared spectroscopy. The UV–Vis titrations were performed to estimate the stability constant values of the respective complexes with Cu(2+) ion. Changes in UV–Vis absorption spectra and IR spectra of compound 6 under various concentrations of Cu(2+) ion in methanol suggest formation of very unstable complex. The structure of ligand 2 has been deduced by X-ray crystallography.