NIR-FT Raman spectroscopy of the stereoisomers of a dinuclear Ru-HAT complex, photoprobe of denatured DNA

Recently, the 3 stereoisomers of the dinuclear complex [Ru(bpy)2]2HAT2+ the racemic A-A and A-A and the meso A-A forms, have been isolated and characterized [1] It has been shown that the racemic and the meso forms, exhibit different luminescence lifetimes of the excited 3MLCT state (Metal to Ligand Charge Transfer). It has been demonstrated that each of the three stereoisomers gives rise to a photo-electron transfer with the guanosine 5′ -monophosphate (GMP) and this, very interestingly, with a different rate. Moreover, in the presence of denatured DNA, there is also a stereospecific behaviour of the dinuclear species. These features underline the interest of using the stereoisomers as specific DNA photoprobes.