Département de chimie moléculaire

A series of new extended planar arom. ligands based on an acridine core (dpac = dipyrido[3,2-a:2',3'-c]acridine (I); dpacF2 = 7,8-difluorodipyrido[3,2-a:2',3'-c]acridine (II); dpacF4 = 6,7,8,9-tetrafluorodipyrido[3,2-a:2',3'-c]acridine (III)) and their resp. RuII complexes were synthesized and extensively studied. The photophys. and theor. studies revealed that Ru-DPAC and Ru-DPACF2 allow emission from a 3MLCTphen/dpac excited state at 597 and 604 nm, resp., whereas the lowest excited state for Ru-DPACF4 shifts from a bright 3MLCTphen/dpac state towards a poorly luminescent 3MLCTdpac state ($łambda$em = 609 nm) owing to the formation of hydrogen bonds with water mols. in the excited state. These complexes exhibit up to sevenfold luminescence enhancement in the presence of complementary and mismatched DNA, demonstrating a strong binding to polynucleotides. The results emphasize the interest in RuII complexes bearing acridine derivs. as DNA interacting agents as a complement to the known phenazine-based derivs. [on SciFinder(R)]