Dicopper(II) complexes of chiral C2-symmetric diamino-bis(2-methylpyridyl) and diamino-bis(2-methylbenzimidazolyl) ligands

Pérez, Viridiana; Monsalvo, Ivan; Demare, Patricia; Gómez‐Vidales, Virginia; Regla, Ignacio; Castillo, Iván

doi:10.1016/j.inoche.2010.12.008

Cited by 7 publications

(2 citation statements)

References 15 publications

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“…Probably due to its presence in equilibrium with the corresponding hydroxido species [Cu(L)(OH)] + , which was proved to produce a dinuclear with bridged hydroxido derivatives (Scheme 2). This was supported by the isolation and structural characterization of [(L 1 )Cu2(µ-OH)(H2O)(OAc)2Cl] [51].…”

Section: Solution Study and Stability Of Complexesmentioning

confidence: 83%

Copper(II) Complexes with Tetradentate Piperazine-Based Ligands: DNA Cleavage and Cytotoxicity

et al. 2021

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Five-coordinate Cu(II) complexes, [Cu(Ln)X]ClO4/PF6, where Ln = piperazine ligands bearing two pyridyl arms and X = ClO4− for Ln = L1 (1-ClO4), L2 (2-ClO4), L3 (3-ClO4), and L6 (6-ClO4) as well as [Cu(Ln)Cl]PF6 for Ln = L1 (1-Cl), L4 (4-Cl), and L5 (5-Cl) have been synthesized and characterized by spectroscopic techniques. The molecular structures of the last two complexes were determined by X-ray crystallography. In aqueous acetonitrile solutions, molar conductivity measurements and UV-VIS spectrophotometric titrations of the complexes revealed the hydrolysis of the complexes to [Cu(Ln)(H2O)]2+ species. The biological activity of the Cu(II) complexes with respect to DNA cleavage and cytotoxicity was investigated. At micromolar concentration within 2 h and pH 7.4, DNA cleavage rate decreased in the order: 1-Cl ≈ 1-ClO4 > 3-ClO4 ≥ 2-ClO4 with cleavage enhancements of up to 23 million. Complexes 4-Cl, 5-Cl, and 6-ClO4 were inactive. In order to elucidate the cleavage mechanism, the cleavage of bis(4-nitrophenyl)phosphate (BNPP) and reactive oxygen species (ROS) quenching studies were conducted. The mechanistic pathway of DNA cleavage depends on the ligand’s skeleton: while an oxidative pathway was preferable for 1-Cl/1-ClO4, DNA cleavage by 2-ClO4 and 3-ClO4 predominantly proceeds via a hydrolytic mechanism. Complexes 1-ClO4, 3-ClO4, and 5-Cl were found to be cytotoxic against A2780 cells (IC50 30–40 µM). In fibroblasts, the IC50 value was much higher for 3-ClO4 with no toxic effect.

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Section: Solution Study and Stability Of Complexesmentioning

confidence: 83%

Copper(II) Complexes with Tetradentate Piperazine-Based Ligands: DNA Cleavage and Cytotoxicity

et al. 2021

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“…[1‐Me‐2‐(C 6 H 12 N 4 )CH 2 C 7 H 4 N 2 ]Cl ( A ) : Hexamethylenetetramine (140 mg, 1.00 mmol) was added to a chloroform solution (20 mL) of 1‐methyl‐2‐(chloromethyl)benzimidazole31 (180 mg, 1.00 mmol) in a round‐bottomed flask. The mixture was stirred at 60 °C until an off‐white solid started to deposit after 2, 7, 14, and 24 h. After each of these intervals of time, the solid was collected by filtration and the solution further heated and stirred to obtain the precursor 1‐methyl‐2‐(hexamethylenetetraaminomethyl)benzimidazolium chloride ( A ).…”

Section: Methodsmentioning

confidence: 99%

Copper Versus Thioether‐Centered Oxidation: Mechanistic Insights into the Non‐Innocent Redox Behavior of Tripodal Benzimidazolylaminothioether Ligands

Martínez‐Alanis¹,

Sánchez-Eguía²,

Ugalde‐Saldívar³

et al. 2013

Chemistry A European J

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A series of Cu(+) complexes with ligands that feature varying numbers of benzimidazole/thioether donors and methylene or ethylene linkers between the central nitrogen atom and the thioether sulfur atoms have been spectroscopically and electrochemically characterized. Cyclic voltammetry measurements indicated that the highest Cu(2+)/Cu(+) redox potentials correspond to sulfur-rich coordination environments, with values decreasing as the thioether donors are replaced by nitrogen-donating benzimidazoles. Both Cu(2+) and Cu(+) complexes were studied by DFT. Their electronic properties were determined by analyzing their frontier orbitals, relative energies, and the contributions to the orbitals involved in redox processes, which revealed that the HOMOs of the more sulfur-rich copper complexes, particularly those with methylene linkers (-N-CH2-S-), show significant aromatic thioether character. Thus, the theoretically predicted initial oxidation at the sulfur atom of the methylene-bridged ligands agrees with the experimentally determined oxidation waves in the voltammograms of the NS3- and N2S2-type ligands as being ligand-based, as opposed to the copper-based processes of the ethylene-bridged Cu(+) complexes. The electrochemical and theoretical results are consistent with our previously reported mechanistic proposal for Cu(2+)-promoted oxidative C-S bond cleavage, which in this work resulted in the isolation and complete characterization (including by X-ray crystallography) of the decomposition products of two ligands employed, further supporting the novel reactivity pathway invoked. The combined results raise the possibility that the reactions of copper-thioether complexes in chemical and biochemical systems occur with redox participation of the sulfur atom.

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Benzimidazole-derived calix[4]arenes with polymerizable styrene groups and their Cu(II) complexes

Cante-Mota

Moreno‐Alcántar

Flores-Álamo

et al. 2013

Inorganica Chimica Acta

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Dicopper(II) complexes of chiral C2-symmetric diamino-bis(2-methylpyridyl) and diamino-bis(2-methylbenzimidazolyl) ligands

Cited by 7 publications

References 15 publications

Copper(II) Complexes with Tetradentate Piperazine-Based Ligands: DNA Cleavage and Cytotoxicity

Copper(II) Complexes with Tetradentate Piperazine-Based Ligands: DNA Cleavage and Cytotoxicity

Copper Versus Thioether‐Centered Oxidation: Mechanistic Insights into the Non‐Innocent Redox Behavior of Tripodal Benzimidazolylaminothioether Ligands

Benzimidazole-derived calix[4]arenes with polymerizable styrene groups and their Cu(II) complexes

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