Dirhodium(II,II) complexes are shown to possess excited states accessible with visible to near-IR light that are able to undergo reactivity for applications ranging from photochemotherapy to solar energy conversion. In particular, cis– [Rh2(DPhF)2(bncn)2]2+ (DPhF = N,N'-diphenylformamidinate, bncn = benzocinnoline; 1) is able to act as a single-molecule photocatalyst for the generation of hydrogen from acidic solutions in the presence of a sacrificial electron donor when irradiated with red/near-IR light. The water solubility of 1 led us to investigate its photoreactivity towards DNA. Complex 1 is able to photocleave DNA at pH = 5.3 upon irradiation with visible light, however, no photocleavage is observed at neutral pH. The binding of 1 to DNA was investigated and likely interacts with the polyanionic double helix through multiple modes, including electrostatic interactions, covalent coordination, and/or partial intercalation.
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