Dinuclear Cu(II) complexes, [Cu(2) (salophen)(2) ] (1) and [Cu(2) (salen)(2) ] (2), with Schiff bases derived from salicylaldehyde and o-phenylenediamine (ophen) or ethylenediamine (en) were synthesized and characterized. They exhibit square-planar geometry with CuN(2) O(2) coordination, where the dianionic Schiff base acts as a tetradentate N(2) O(2) donor ligand. Calf thymus (CT)-DNA Binding studies revealed that the complexes possess good binding propensities (K(b) =3.13×10(5) for 1 and K(b) =2.99×10(5) M(-1) for 2). They show good DNA-cleavage abilities under oxidative and hydrolytic conditions. Complex 1 binds and cleaves DNA more efficiently as compared to 2 due to the presence of an extended aromatic phenyl ring which might be involved in an additional stacking interaction with DNA bases. From the kinetic experiments, hydrolytic DNA-cleavage rate constants were determined as 1.54 for 1 and 0.72 h(-1) for 2. The nuclease activities of 1 and 2 are significant, giving rise to (2.03-2.88)×10(7) -fold rate enhancement compared to non-catalyzed DNA cleavage.
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http://dx.doi.org/10.1002/cbdv.201000153 | DOI Listing |
Molecules
December 2024
Department of Chemical Sciences, University of Padova, Via Marzolo 1, 35131 Padova, Italy.
This study focuses on the use of three isostructural NO donor ligands, specifically known to form complexes with copper ions, to chelate Cu(II) from aqueous solutions. The corresponding Cu(II) complexes feature a dinuclear copper core mimicking the active site of natural superoxide dismutase (SOD) enzymes while also creating a coordination environment favorable for catalase (CAT) activity, being thus appealing as catalytic antioxidant systems. Given the critical role of copper dysregulation in the pathophysiology of Alzheimer's disease (AD), these complexes may help mitigate the harmful effects of free Cu(II) ions: the goal is to transform copper's reactive oxygen species (ROS)-generating properties into beneficial ROS-scavenging action.
View Article and Find Full Text PDFChemistry
November 2024
Department of Chemistry, Bielefeld Universtity, Universitätsstr. 25, D-33615, Bielefeld, Germany.
We have developed a family of dinuclear complexes using 2,7-disubstituted 1,8-naphthalenediol ligands that bind by molecular recognition to two neighboring phosphate diesters of the DNA backbone with the dinuclear Cu and Ni complexes exhibiting a severe cytotoxicity for human cancer cells. To increase the binding affinity, we intended to synthesize the corresponding dinuclear Fe complex. Surprisingly, we obtained a tetranuclear Fe perylene-based complex instead of the expected dinuclear Fe naphthalene-based complex.
View Article and Find Full Text PDFJ Mol Graph Model
January 2025
Department of Medicinal and Applied Chemistry, Kaohsiung Medical University, Kaohsiung 80708, Taiwan; Department of Medical Research, Kaohsiung Medical University Hospital, Kaohsiung 80708, Taiwan.
J Inorg Biochem
January 2025
Department of Chemistry, University of South Florida, Tampa, FL 33620-5250, USA; Institute of Drug Discovery Technology, Ningbo University, Ningbo, Zhejiang 315211, PR China. Electronic address:
Angew Chem Int Ed Engl
October 2024
Universität Göttingen, Institut für Anorganische Chemie, Tammannstrasse 4, D-37077, Göttingen, Germany.
Hydrogen bonds involving the oxygen atoms of intermediates that result from copper-mediated O activation play a key role for controlling the reactivity of Cu/O active sites in metalloenzymes and synthetic model complexes. However, structural insight into H-bonding in such transient species as well as thermodynamic information about proton transfer to or from the O-derived ligands is scarce. Here we present a detailed study of the reversible interconversion of a μ-peroxodicopper(II) complex ([1]) and its μ-hydroperoxo congener ([2]) via (de)protonation, including the isolation and structural characterization of several H-bond donor (HBD) adducts of [1] and the determination of binding constants.
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