title: Luminescent properties of ruthenium(II) complexes with sterically expansive ligands bound to DNA defects.
abstract: A new family of ruthenium(II) complexes with sterically expansive ligands for targeting DNA defects was prepared, and their luminescent responses to base pair mismatches and/or abasic sites were investigated. Design of the complexes sought to combine the mismatch specificity of sterically expansive metalloinsertors, such as [Rh(bpy)2(chrysi)](3+) (chrysi = chrysene-5,6-quinone diimine), and the light switch behavior of [Ru(bpy)2(dppz)](2+) (dppz = dipyrido[3,2-a:2',3'-c]phenazine). In one approach, complexes bearing analogues of chrysi incorporating hydrogen-bonding functionality similar to dppz were synthesized. While the complexes show luminescence only at low temperatures (77 K), competition experiments with [Ru(bpy)2(dppz)](2+) at ambient temperatures reveal that the chrysi derivatives preferentially bind DNA mismatches. In another approach, various substituents were introduced onto the dppz ligand to increase its steric bulk for mismatch binding while maintaining planarity. Steady state luminescence and luminescence lifetime measurements reveal that these dppz derivative complexes behave as DNA "light switches" but that the selectivity in binding and luminescence with mismatched/abasic versus well-matched DNA is not high. In all cases, luminescence depends sensitively upon structural perturbations to the dppz ligand.
authors.affiliation: Division of Chemistry and Chemical Engineering, California Institute of Technology , Pasadena, California 91125, United States.
authors.forename: Anna J
authors.initials: AJ
authors.lastname: McConnell
authors.forename: Mi Hee
authors.initials: MH
authors.lastname: Lim
authors.forename: Eric D
authors.initials: ED
authors.lastname: Olmon
authors.forename: Hang
authors.initials: H
authors.lastname: Song
authors.forename: Elizabeth E
authors.initials: EE
authors.lastname: Dervan
authors.forename: Jacqueline K
authors.initials: JK
authors.lastname: Barton
mesh_terms: D004247:DNA / Q000737:chemistry / Q000187:drug effects*; D008024:Ligands; D049449:Luminescence; D008163:Luminescent Measurements; D015394:Molecular Structure; D009942:Organometallic Compounds / Q000138:chemical synthesis / Q000737:chemistry / Q000494:pharmacology*; D012428:Ruthenium / Q000737:chemistry*; D013329:Structure-Activity Relationship
chemical_list: D008024:Ligands; D009942:Organometallic Compounds; D012428:Ruthenium; D004247:DNA