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Efficient DNA Cleavage Induced by Copper(II) Complexes of Hydrolysis Derivatives of 2,4,6‐Tri(2‐pyridyl)‐1,3,5‐triazine in the Presence of Reducing Agents
Author(s) -
Borrás Joaquín,
Alzuet Gloria,
GonzálezAlvarez Marta,
GarcíaGiménez Jose L.,
Macías Benigno,
LiuGonzález Malva
Publication year - 2007
Publication title -
european journal of inorganic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.667
H-Index - 136
eISSN - 1099-0682
pISSN - 1434-1948
DOI - 10.1002/ejic.200600821
Subject(s) - chemistry , amide , copper , square pyramidal molecular geometry , crystallography , crystal structure , coordination sphere , hydrolysis , tetragonal crystal system , stereochemistry , coordination geometry , medicinal chemistry , molecule , hydrogen bond , organic chemistry
The reaction of 2,4,6‐tri(pyridyl)‐1,3,5‐triazine (ptz) and copper(II) salts in dmf/water (1:1) results in the hydrolysis of ptz and formation of the anions bis(2‐pyridylcarbonyl)amide (ptO 2 – ) and bis(2‐pyridylamine)amide (ptN 2 – ), which are found in the complexes [Cu(ptN 2 )(OAc)] · 3H 2 O ( 1 ), [Cu(ptO 2 )(OAc)(H 2 O)] · H 2 O ( 2 ), [Cu(ptN 2 )(for)] · 3H 2 O ( 3 ) (for = formate), [Cu(ptO 2 )(for)(H 2 O)] ( 4 ), [Cu(ptO 2 )(benz)] · H 2 O ( 5 ) (benz = benzoate), and [Cu(ptO 2 )F(H 2 O)] 2 · 3H 2 O ( 6 ). This report includes the chemical and spectroscopic characterization of all these complexes along with the crystal structures of 4 – 6 . The coordination spheres of Cu II in 4 and 5 are best described as distorted tetragonal square pyramidal for the former and distorted square planar for the latter. The crystal structure of 6 shows the presence of two discrete monomeric [Cu(ptO 2 )F(H 2 O)] entities in the crystallographic asymmetric unit in which both copper(II) ions have a distorted square‐pyramidal coordination geometry. The binding of the complexes to DNA has been investigated with the aid of viscosity and thermal denaturation studies, both of which indicate that the interaction is probably due to the outer‐sphere mechanism. The ability of the compounds to cleave DNA has also been tested. Efficient oxidative cleavage was observed in the presence of a mild reducing agent (ascorbate) and dioxygen. Mechanistic studies with reactive oxygen species (ROS) scavengers confirm that hydrogen peroxide, the hydroxyl radical, singlet oxygen‐like species, and the superoxide anion are necessary diffusible intermediates in the scission process. A mechanism involving either the Fenton or theHaber–Weiss reaction plus the formation of copper oxene species is proposed for the DNA cleavage mediated by these compounds.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)