Photoinduced intercalation and coordination of a dirhodium complex to DNA: dual DNA binding.
Two new complexes, cis-H,H-[Rh2 (OCCH3 NH)2 (LL)(CH3 CN)2 ](2+) , where LL=bpy (2, bpy=2,2'-bipyridine) and dppz (3, dppz=dipyrido[3,2-a:2',3'-c]phenazine), were prepared from the reaction of cis-H,H-[Rh2 (OCCH3 NH)2 (CH3 CN)6 ](2+) (1) with the corresponding bidentate ligand. The bpy and dppz ligands chelate to the same rhodium atom and are positioned trans to the amidato N atoms, as determined by the single crystal X-ray structure of 2. Irradiation of 2 and 3 with visible light in water results in the exchange of one CH3 CNeq ligand for an H2 O molecule with quantum yields, Φ400 , of 0.040 and 0.044, respectively (λirr =400 nm). The identities of the photoproducts of 2 and 3 were determined to be cis-H,H-[Rh2 (OCCH3 NH)2 (L)(H2 O)(CH3 CN)](2+) , where L is bpy (4) and dppz (5), respectively. Mobility shift assays show that 4 crosslinks double-stranded DNA, and ESI-MS experiments indicate that both 4 and 5 form covalent adducts with single-stranded DNA. In addition, relative viscosity and 2D NMR experiments show that the dppz ligand of 5 also intercalates into DNA upon irradiation, making 3 a dual-binding agent that both intercalates and covalently binds to DNA upon the absorption of visible light.
['Palmer|Alycia M|AM|', 'Burya|Scott J|SJ|', 'Gallucci|Judith C|JC|', 'Turro|Claudia|C|']
D015082:2,2'-Dipyridyl D056831:Coordination Complexes D018360:Crystallography, X-Ray D004277:DNA, Single-Stranded D007364:Intercalating Agents D008027:Light D009682:Magnetic Resonance Spectroscopy D008968:Molecular Conformation D011789:Quantum Theory D012238:Rhodium D021241:Spectrometry, Mass, Electrospray Ionization D014783:Viscosity
intercalation dirhodium dual binding photo-active compounds photodynamic therapy