A synthetic and photophysical study of ruthenium polypyridyl enantiomers binding to DNA

Abstract

The luminescent ONA probe [Ru(phen)2dppz]2+, ruthenium (bis-1,10-phenanthroline dipyrido[3,2-a:2',3'-c]phenazine, was the first tris-bidentate ruthenium complex to be shown unequivocally to intercalate to DNA, which it achieves via insertion of the extended dppz ligand. This complex has demonstrated its potential as a DNA probe, courtesy of its luminescent 'light-switch on' effect. Since its discovery and subsequent resolution into its constituent A and Δ enantiomers, many analogues of the [Ru(phen)2dppz]2+ complex have been synthesised and scrutinised for any potential attributes. One such analogue is [Ru(TAP)2dppz]2+ ruthenium (bis,-1,4,5,8- tetraazaphenanthrene dipyrido[3,2-a;2',3'-c]phenazine, which demonstrates the 'lightswitch off' effect and is sufficiently oxidising in its 3MLCT excited state to cause photooxidative damage to DNA, leading to strand scission.