Homogeneous catalysis: Kinetics and mechanism of oxidation of Ru(II) sensitizers by inorganic peroxides

Chitradevi, Radhakrishnan; Anandan, Sambandam; Maruthamuthu, P.

doi:10.1007/s11144-008-5217-6

Cited by 4 publications

(2 citation statements)

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“…6), 50% DNA cleavage is reached within 30 minutes, and the amount of form II reaches the maximum and then remains constant. It is well known that in the presence of H 2 O 2 as an oxidizing agent, Ru(II) species is oxidised to Ru(III) species leading to the formation of more accessible and reactive oxygen species (OH • ) by the Fenton type mechanism, 60 causing DNA cleavage. When the standard radical scavengers are added to the reaction mixture a dramatic (DMSO, a hydroxide radical quencher) to significant (NaN 3 , a singlet oxygen quencher) inhibition in DNA cleavage is observed (Fig.…”

Section: Dna Cleavage Studiesmentioning

confidence: 99%

New ruthenium(ii) arene complexes of anthracenyl-appended diazacycloalkanes: effect of ligand intercalation and hydrophobicity on DNA and protein binding and cleavage and cytotoxicity

et al. 2014

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A series of half-sandwich Ru(II) arene complexes of the type [Ru(η(6)-arene)(L)Cl](PF6) 1-4, where arene is benzene (1, 2) or p-cymene (3, 4) and L is N-methylhomopiperazine (L1) or 1-(anthracen-10-ylmethyl)-4-methylhomopiperazine (L2), has been isolated and characterized by using spectral methods. The X-ray crystal structures of 2, 3 and 4 reveal that the compounds possess a pseudo-octahedral "piano-stool" structure equipped with the arene ligand as the seat and the bidentate ligand and the chloride ion as the legs of the stool. The DNA binding affinity determined using absorption spectral titrations with CT DNA and competitive DNA binding studies varies as 4 > 2 > 3 > 1, depending upon both the arene and diazacycloalkane ligands. Complexes 2 and 4 with higher DNA binding affinities show strong hypochromism (56%) and a large red-shift (2, 10; 4, 11 nm), which reveals that the anthracenyl moiety of the ligand is stacked into the DNA base pairs and that the arene ligand hydrophobicity also dictates the DNA binding affinity. In contrast, the monocationic complexes 1 and 3 are involved in electrostatic binding in the minor groove of DNA. The enhancement in viscosities of CT DNA upon binding to 2 and 4 are higher than those for 1 and 3 supporting the DNA binding modes of interaction inferred. All the complexes cleave DNA effectively even in the absence of an external agent and the cleavage ability is enhanced in the presence of an activator like H2O2. Tryptophan quenching measurements suggest that the protein binding affinity of the complexes varies as 4 > 2 > 3 > 1, which is the same as that for DNA binding and that the fluorescence quenching of BSA occurs through a static mechanism. The positive ΔH(0) and ΔS(0) values for BSA binding of complexes indicate that the interaction between the complexes and BSA is mainly hydrophobic in nature and the energy transfer efficiency has been analysed according to the Förster non-radiative energy transfer theory. The variation in the ability of complexes to cleave BSA in the presence of H2O2, namely, 4 > 2 > 3 > 1, as revealed from SDS-PAGE is consistent with their strong hydrophobic interaction with the protein. The IC50 values of 1-4 (IC50: 1, 28.1; 2, 23.1; 3, 26.2; 4, 16.8 μM at 24 h; IC50: 1, 19.0; 2, 15.9; 3, 18.1; 4, 9.7 μM at 48 h) obtained for MCF 7 breast cancer cells indicate that they have the potency to kill cancer cells in a time dependent manner, which is similar to cisplatin. The anticancer activity of complexes has been studied by employing various biochemical methods involving different staining agents, AO/EB and Hoechst 33258, which reveal that complexes 1-4 establish a specific mode of cell death in MCF 7 breast cancer cells. The comet assay has been employed to determine the extent of DNA fragmentation in cancer cells.

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Section: Dna Cleavage Studiesmentioning

confidence: 99%

New ruthenium(ii) arene complexes of anthracenyl-appended diazacycloalkanes: effect of ligand intercalation and hydrophobicity on DNA and protein binding and cleavage and cytotoxicity

et al. 2014

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“…Organic peroxides (OPs) [1][2][3][4][5][6] and inorganic peroxides [7] possess a latent hazard for which the peroxy radical is a pivotal factor. It may result in deflagration or detonation from contact with external thermal sources, acid-catalyzed, base-catalyzed, metallic compounds, and pollutants, etc.…”

Section: Introductionmentioning

confidence: 99%

Fire and Thermal Hazard Analyses of Industrial Zeolite Catalysis for Phenol Production

Tsai

Guo

2012

AMR

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Effective and significant improvement in the technology for the production of phenol has been made over the past decade. New catalysts and processes have been employed to produce a great deal of phenol in the cumene hydroperoxide (CHP) industry. Fire and thermal explosion of CHP has occurred in Taiwan. Therefore, thermal hazard and reactive risk information has been analyzed in this research. Zeolite is employed as a catalyst for the CHP process. The aim of this investigation was to determine the inherent safety of the phenol production process. Effective manufacturing of phenol and safe handling procedures are significant issues for industrial applications. In view of loss prevention, calorimetric application and model evaluations to integrate thermal hazard development are necessary and useful for inherently safer design.

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Characterization of [Ru(bpy)2(diamine)]2+ complexes and their DNA binding and cleavage, BSA interaction, cytotoxic, and anticancer mechanistic properties

et al. 2022

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Homogeneous catalysis: Kinetics and mechanism of oxidation of Ru(II) sensitizers by inorganic peroxides

Cited by 4 publications

References 10 publications

New ruthenium(ii) arene complexes of anthracenyl-appended diazacycloalkanes: effect of ligand intercalation and hydrophobicity on DNA and protein binding and cleavage and cytotoxicity

New ruthenium(ii) arene complexes of anthracenyl-appended diazacycloalkanes: effect of ligand intercalation and hydrophobicity on DNA and protein binding and cleavage and cytotoxicity

Fire and Thermal Hazard Analyses of Industrial Zeolite Catalysis for Phenol Production

Characterization of [Ru(bpy)2(diamine)]2+ complexes and their DNA binding and cleavage, BSA interaction, cytotoxic, and anticancer mechanistic properties

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