Synergistic properties of biological interest of a ruthenium (II) compound

Abstract

This work reports the synthesis, characterization and verification of synergistic properties of a nitrite ruthenium(II) compound [Ru(tpy)(dppz)(NO2)](PF6) (tpy = 2,2′:6′,2″-terpyridine; dppz = dipyrido[3,2-a:2’,3’-c]phenazine), which is compared to its chlorine precursor [Ru(tpy)(dppz)(Cl)](PF6). 1H-NMR and IR analysis shows the absence of any isomers other than the N-bonded nitrite species. Electronic spectroscopy analysis reveals the influence of the π-acceptor NO2- ligand on the structure of the complex, shifting the MLCT bands to higher energies and increasing the lifetime of its excited state, measured by fs-TA and TCSPC spectroscopies. The nitrosyl species [Ru(tpy)(dppz)(NO)]3+ is highly unstable due to the low electronic density on Ru center, as shown by pKa measurements and DFT calculations. The nitrite compound proved to be able to interact strongly with DNA, generate 1O2 and release NO by light stimulation, making it an interesting example of a synergetic compound possessing these properties simultaneously. Improving these results by adjusting the tridentate ligand provides a strategy to develop new Ru candidates for metallofarmaceuticals as anticancer drugs