title: Ternary iron(III) complex showing photocleavage of DNA in the photodynamic therapy window.
abstract: A new ternary iron(III) complex [FeL(dpq)] containing dipyridoquinoxaline (dpq) and 2,2-bis(3,5-di-tert-butyl-2-hydroxybenzyl)aminoacetic acid (H3L) is prepared and structurally characterized by X-ray crystallography. The high-spin complex with a FeN3O3 core shows a quasi-reversible iron(III)/iron(II) redox couple at -0.62 V (vs SCE) in DMF/0.1 M TBAP and a broad visible band at 470 nm in DMF/Tris buffer. Laser photoexcitation of this phenolate (L)-to-iron(III) charge-transfer band at visible wavelengths including red light of >or=630 nm leads to cleavage of supercoiled pUC19 DNA to its nicked circular form via a photoredox pathway forming hydroxyl radicals.
authors.affiliation: Department of Inorganic and Physical Chemistry, Indian Institute of Science, Bangalore 560012, India.
authors.forename: Mithun
authors.initials: M
authors.lastname: Roy
authors.forename: Sounik
authors.initials: S
authors.lastname: Saha
authors.forename: Ashis K
authors.initials: AK
authors.lastname: Patra
authors.forename: Munirathinam
authors.initials: M
authors.lastname: Nethaji
authors.forename: Akhil R
authors.initials: AR
authors.lastname: Chakravarty
mesh_terms: D004247:DNA / Q000737:chemistry*; D005290:Ferric Compounds / Q000737:chemistry*; D008958:Models, Molecular; D015394:Molecular Structure; D010777:Photochemistry; D010778:Photochemotherapy
chemical_list: D005290:Ferric Compounds; D004247:DNA