Synthesis, characterization, and photoactivated DNA cleavage by copper (II)/cobalt (II) mediated macrocyclic complexes.

ABSTRACT

We report the synthesis of new photonuclease consisting of two Co(II)/Cu(II) complexes of macrocyclic fused quinoline. Metal complexes are [MLX(2)], type where M = Co(II) (5), Cu(II) (6), and X = Cl, and are well characterized by elemental analysis, Fourier transform infrared spectroscopy, (1)H-NMR and electronic spectra. We have shown that photocleavage of plasmid DNA is markedly enhanced when this ligand is irradiated in the presence of Cu(II), and more so than that of cobalt. The chemistry of ternary and binary Co(II) complexes showing efficient light induced (360 nm) DNA cleavage activity is summarized. The role of the metal in photoinduced DNA cleavage reactions is explored by designing complex molecules having macrocyclic structure. The mechanistic pathways are found to be concentration dependent on Co(II)/Cu(II) complexes and the photoexcitation energy photoredox chemistry. Highly effective DNA cleavage ability of 6 is attributed to the effective cooperation of the metal moiety.