DNA Intercalating Near-Infrared Luminescent Lanthanide Complexes Containing Dipyrido[3,2-a:2',3'-c]phenazine (dppz) Ligands: Synthesis, Crystal Structures, Stability, Luminescence Properties and CT-DNA Interaction

Pyrrolidine-Derived Phenanthroline Diamides: An Influence of Fluorine Atoms on the Coordination of Lu(III) and Some Other f-Elements and Their Solvent Extraction

Three pyrrolidine-derived phenanthroline diamides were studied as ligands for lutetium trinitrate. The structural features of the complexes have been studied using various spectral methods and X-ray. The presence of halogen atoms in the structure of phenanthroline ligands has a significant impact on both the coordination number of lutetium and the number of solvate water molecules in the internal coordination sphere. The stability constants of complexes with La(NO3)3, Nd(NO3)3, Eu(NO3)3, and Lu(NO3)3 were measured to demonstrate higher efficiency of fluorinated ligands. NMR titration was performed for this ligand, and it was found that complexation with lutetium leads to an approximately 13 ppm shift of the corresponding signal in the 19F NMR spectrum. The possibility of formation of a polymeric oxo-complex of this ligand with lutetium nitrate was demonstrated. Experiments on the liquid–liquid extraction of Am(III) and Ln(III) nitrates were carried out to demonstrate advantageous features of chlorinated and fluorinated pyrrolidine diamides.

One pot three component synthesis of DNA targeting phototoxic Ru(II)-p-cymene dipyrido[3,2-a:2',3'-c]phenazine analogues

We have developed a one pot three component synthetic protocol for half-sandwich Ru(II)-p-cymene dipyrido[3,2-a:2',3'-c]phenazine analogues for selective cancer therapy under light irradiation. On average, the cytotoxicity of all the complexes is indeed doubled upon light irradiation and also exhibited significant photo and dark selectivity against cancer cells with respect to normal cells. Out of five Ru(II) complexes (RuL1-RuL5), [(η⁶-p-cymene)Ru^IICl(K²-N,N-11-nitrodipyrido[3,2-a:2',3'-c]phenazine]PF₆ (RuL4) exhibited the best phototoxicity (lowest IC₅₀ under light irradiation). Intracellular ROS generation was studied by the 2',7'-dichlorofluorescein diacetate (DCFH-DA) assay. Moreover, these complexes exhibited a strong serum albumin and DNA binding capacity. These complexes also exhibited good stability in 10% DMSO-buffer and under 1 mM GSH conditions. Overall, the remarkable photocytotoxic efficacy of new Ru(II)-p-cymene dipyrido[3,2-a:2',3'-c]phenazine analogues (RuL1-RuL5) makes them potential photochemotherapeutics as an alternative of current PDT agents.