Azo ligand as new corrosion inhibitor for copper metal: Spectral, thermal studies and electrical conductivity of its novel transition metal complexes

•Anew azo ligand (L) was prepared, characterized, and has been studied as corrosion inhibitor for copper metal in acidic medium.•The tetradentate azo ligand (L) coordinates as bidentate ligand with different metal ions.•Spectral studies, thermal and elemental analyses exhibited that the studied metal complexes have octahedral structure.•Azo ligand and its metal complexes exhibited semiconducting nature, the electrical conductivity increase in the order: Cr (III) ˂ Zr (IV) ˂ Ru (III) ˂ Hf (IV) ˂ Fe (III)•Azo ligand (L) and its metal complexes can be used in industrial applications.