Synthesis of ruthenium (II) compounds with 2,2’: 6’,2’’-terpyridine derived ligands

Abstract

Three new ligands ((4’-(4-bromophenyl)-2,2’:6’,2’’-terpyridine (4a), 4’-(4-aniline)-2,2’:6’,2’’-terpyridine (4b), 4’-(2-aminopyridine-3-yl)-2,2’:6’,2’’-terpyridine (4c)) have been prepared by combination of Kröhnke condensation and Michael addition. Compound 4a reacts with RuCl3·3H2O in methanol producing [Ru(Brterpy)Cl3] (5a). The reaction of 5a with bidentate ligands, namely 2,2’-bipyridine and 1,10-phenanthroline, allows to obtain two monofunctional ruthenium (II) compounds: [Ru(Bipy)(Brterpy)Cl]Cl (7a) and [Ru(Brterpy)Cl(Phen)]Cl (7a’), respectively. The ligands and the ruthenium (II) complexes were characterized by infrared spectroscopy (IR) and mono- and bidimensional NMR spectroscopies. The metal compounds were also characterized by mass spectrometry. Furthermore, the study of the absorbance by UV-Vis and their fluorescence by the emission and excitation spectra were carried out. Finally, DNA interaction with complexes 7a and 7a’ was studied contrasting the effect with non-irradiated and irradiated samples with photoactivating wavelength light. The evidence from this study suggests that both complexes can act has photosensitizers