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Photoinduced Intercalation and Coordination of a Dirhodium Complex to DNA: Dual DNA Binding
Author(s) -
Palmer Alycia M.,
Burya Scott J.,
Gallucci Judith C.,
Turro Claudia
Publication year - 2014
Publication title -
chemmedchem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.817
H-Index - 100
eISSN - 1860-7187
pISSN - 1860-7179
DOI - 10.1002/cmdc.201402004
Subject(s) - chemistry , intercalation (chemistry) , ligand (biochemistry) , denticity , crystallography , covalent bond , stereochemistry , adduct , phenazine , molecule , photochemistry , crystal structure , inorganic chemistry , biochemistry , receptor , organic chemistry
Two new complexes, cis ‐ H , H ‐[Rh 2 (OCCH 3 NH) 2 (LL)(CH 3 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 ‐[Rh 2 (OCCH 3 NH) 2 (CH 3 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 CH 3 CN eq ligand for an H 2 O molecule with quantum yields, Φ 400 , of 0.040 and 0.044, respectively ( λ irr =400 nm). The identities of the photoproducts of 2 and 3 were determined to be cis ‐ H , H ‐[Rh 2 (OCCH 3 NH) 2 (L)(H 2 O)(CH 3 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.