Synthesis, characterization and spectroscopic investigation of azo-porphyrins

A series of novel covalently connected azonaphthalene porphyrin derivatives were prepared by linking azonaphthalene groups through a diazo-coupling reaction. They were characterized by UV–vis, IR, 1H NMR and ESI-MS spectroscopic techniques. Azo–hydrazone tautomerism was studied using 1H NMR and UV–vis techniques. The two chromophores of these derivatives exhibited their absorption spectroscopic properties and the effect of solvent upon the absorption ability was examined. In the fluorescence emission spectra, intermolecular fluorescence quenching was detected.