Direct DNA Photocleavage by a New Intercalating Dirhodium(II/II) Complex:  Comparison to Rh2(μ-O2CCH3)4

• Published in: Inorganic chemistry 2004-04, Vol.43 (8), p.2450-2452
• Main Authors: Bradley, Patricia M, Angeles-Boza, Alfredo M, Dunbar, Kim R, Turro, Claudia
• Format: Article
• Language: English
• Subjects: Antineoplastic Agents - chemical synthesis; Antineoplastic Agents - chemistry; Antineoplastic Agents - pharmacology; DNA - chemistry; DNA Damage - drug effects; DNA Damage - radiation effects; Models, Molecular; Molecular Structure; Organometallic Compounds - chemical synthesis; Organometallic Compounds - chemistry; Organometallic Compounds - pharmacology; Oxidation-Reduction; Photochemistry; Rhodium - chemistry
• ISSN: 0020-1669; 1520-510X
• DOI: 10.1021/ic035424j

Transition metal complexes possessing the intercalating dppz ligand (dppz = dipyrido[3,2-a:2‘,3‘-c]phenazine) typically bind ds-DNA through intercalation (K b ∼ 105−106 M-1), and DNA photocleavage by these complexes with visible light proceeds through the generation of a reactive oxygen species. The DNA binding and photocleavage by [Rh2(μ-O2CCH3)2(η1-O2CCH3)(CH3OH)(dppz)]+ (2) is reported and compared to that of Rh2(μ-O2CCH3)4 (1). Spectral changes and an increase in viscosity provide evidence for the intercalation of 2 to double stranded DNA with K b = 1.8 × 105 M-1. DNA photocleavage by 2 is observed upon irradiation with λirr > 395 nm both in air and deoxygenated solution. DNA photocleavage is not observed for 1 or free dppz ligand under these irradiation conditions. The coupling of a single dppz ligand to a dirhodium(II/II) bimetallic core in 2 provides a means to access oxygen-independent DNA photocleavage with visible light.