“Electro-Photo Switch” and “Molecular Light Switch” Devices Based on Ruthenium(II) Complexes of Modified Dipyridophenazine Ligands:  Modulation of the Photochemical Function through Ligand Design

Arounaguiri, S.; Maiya, Bhaskar G.

doi:10.1021/ic981109z

Cited by 154 publications

(98 citation statements)

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“…These new ligands have been designed so that besides containing the expansively aromatic "dppz" type of structure, they are also endowed with other electroactive subunits that impart special properties for the complexes in the presence of DNA. [18][19][20][21] Some of the complexes containing a non-planar ligand also exhibit interesting properties upon binding to DNA, [22,23] It is well known that the five-membered imidazole ring is a component of the purine bases in DNA. Ji and co-workers have reported a series of imidazole-modified phen/bpy ligands where the imidazole ring is out of the plane of the phen moiety, and also biphenyl derivatives of phen/dppz, all of which help to explain the effect of ligand planarity on the DNA binding strength of the complexes.…”

Section: (Aip)]mentioning

confidence: 99%

Effects of Anthracene and Pyrene Units on the Interactions of Novel Polypyridylruthenium(II) Mixed‐Ligand Complexes with DNA

Mariappan

Maiya

2005

Eur J Inorg Chem

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2‐(9‐Anthryl)‐1H‐imidazo[4,5‐f][1,10]phenanthroline (aip) and [2‐(1‐pyrenyl)‐1H‐imidazo[4,5‐f][1,10]phenanthroline (pyip) and their complexes [Ru(phen)2(aip)]2+ (1) and [Ru(phen)2(pyip)]2+ (2) (phen = 1,10‐phenanthroline) have been synthesized and characterized by elemental analysis, UV/Vis, IR and 1H NMR spectroscopy, FAB‐MS and cyclic voltammetry methods. Both 1 and 2 are redox‐active and undergo oxidation at 1.43 and 1.47 V (vs. SCE), respectively. Both 1 and 2 show only the 3MLCT emission typical of any polypyridylruthenium(II) complex. These new complexes are seen to be excellent binders of calf‐thymus (CT) DNA, as revealed by the results of absorption, luminescence, viscometric titrations, and thermal denaturation studies. These results also indicate that while ruthenium‐bound aip and pyip intercalate within the base pairs of the duplex, the phen moieties act only as spectator ligands in each case. Steady‐state emission studies carried out in aqueous media with and without DNA reveal that [Ru(phen)2(pyip)]2+ is a better “molecular light switch” for DNA than [Ru(phen)2(aip)]2+. Under an identical set of experimental conditions of light and drug dose, the DNA photocleavage ability of [Ru(phen)2(pyip)]2+ is also higher than that of [Ru(phen)2(aip)]2+. “Inhibitor studies” suggest that the oxygen species are mainly responsible for the DNA photocleavage by these complexes. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)

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Section: (Aip)]mentioning

confidence: 99%

Effects of Anthracene and Pyrene Units on the Interactions of Novel Polypyridylruthenium(II) Mixed‐Ligand Complexes with DNA

Mariappan

Maiya

2005

Eur J Inorg Chem

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“…Transition-metal complexes having phenanthroline bases have been extensively used as DNA-cleaving agents, [1][2][3] DNA structural probes, [4,5] DNA photoprobes, [6] DNA molecular light switches, [7][8][9] and for other applications. [10][11][12] Such complexes with their varied coordination environments and versatile redox, spectral and magnetic properties could act as multi-utility model hydrolytic/oxidative nucleases and potential cytotoxic agents.…”

Section: Introductionmentioning

confidence: 99%

Terpyridine Oxovanadium(IV) Complexes of Phenanthroline Bases for Cellular Imaging and Photocytotoxicity in HeLa Cells

et al. 2011

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Oxovanadium(IV) complexes [VO(N‐N‐N)(N‐N)](NO3)2 (1–4) of (4′‐phenyl)‐2,2′:6′,2″‐terpyridine (ph‐tpy in 1 and 2) or (4′‐pyrenyl)‐2,2′:6′,2″‐terpyridine (py‐tpy in 3 and 4) having N‐N as 1,10‐phenanthroline (phen in 1 and 3) or dipyrido[3,2‐a:2′,3′‐c]phenazine (dppz in 2 and 4) are prepared and characterized. The crystal structure of 1 has VO2+ group in VN5O coordination geometry. The terpyridine ligand coordinates in a meridional binding mode. The phen ligand displays a chelating mode of binding with an N‐donor site trans to the vanadyl oxo group. The complexes show a d‐d band in the range of 710–770 nm in aqueous DMF (4:1 v/v). The complexes exhibit an irreversible VIV/VIII redox response near –1.0 V vs. SCE in aqueous DMF/0.1 M KCl. The complexes bind to CT DNA giving Kb values within 3.5 × 105 to 1.2 × 106 M–1. The complexes show poor chemical nuclease activity in dark. Complexes 2–4 show photonuclease activity in UV‐A light of 365 nm forming 1O2 and ·OH. Complex 4 shows DNA photocleavage activity at near‐IR light of 785 nm forming ·OH radicals. Complexes 2 and 4 show significant photocytotoxicity in HeLa cancer cells. Uptake of the complexes in HeLa cells, studied by fluorescence imaging, show predominantly cytosolic localization inside the cells.

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“…10 There are several types of sites in the DNA molecule where binding of metal complexes can occur: (I) between two base pairs (intercalation), (II) in the minor groove, (III) in the major groove, and (IV) on the outside of the helix. 11 Among these complexes, the role of the Pt(II) and Pd(II) complexes is crucial since they can bind to DNA covalently as well as noncovalently. Several reports have shown that palladium complexes are expected to have lower kidney toxicity than cisplatin due to the inability of proteins in the kidney tubules to replace the tightly bound chelate ligands of Pd(II) with sulfydril groups.…”

Section: Introductionmentioning

confidence: 99%

“…[12][13][14][15] Concerning the noncovalent interactions between transition-metal complexes and DNA, they can occur by intercalation, groove binding, or external electrostatic binding. [10][11] Many anticancer drugs are known to interact with DNA to exert their biological activities. Generally, DNA-acting anticancer drugs can be classified into three categories.…”

Section: Introductionmentioning

confidence: 99%

A Thermodynamic Study of New Designed Complex of Ethylendiamine 8-Hydroxyquinolinato Palladium(II) Chloride with Calf Thymus DNA

2009

Bulletin of the Korean Chemical Society

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A Thermodynamic study on the interaction of bovine calf thymus DNA with new designed Pd(II) complex (Ethylendiamine-8-hydroxyquinolinato Palladium(II) chloride) was studied by using isothermal titration calorimetry (ITC) at 27 o C in Tris buffer solution at pH = 7.5. The enthalpies of Pd(II) complex + DNA interaction are reported and analysed in terms of the new solvation theory. It was indicated that there are three identical and non-cooperative sites for Pd(II) complex. The binding of a Pd(II) complex is endothermic with association equilibrium constants of 428.03 mM -1 at 27 o C. The binding of Pd(II) complex can cause some changes in the stability of the DNA at low and high Pd(II) complex concentrations. Our results suggested that this complex might interact with DNA as an intercalator, thus interfering with DNA replication and cell proliferation.

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“Electro-Photo Switch” and “Molecular Light Switch” Devices Based on Ruthenium(II) Complexes of Modified Dipyridophenazine Ligands: Modulation of the Photochemical Function through Ligand Design

Cited by 154 publications

References 10 publications

Effects of Anthracene and Pyrene Units on the Interactions of Novel Polypyridylruthenium(II) Mixed‐Ligand Complexes with DNA

Effects of Anthracene and Pyrene Units on the Interactions of Novel Polypyridylruthenium(II) Mixed‐Ligand Complexes with DNA

Terpyridine Oxovanadium(IV) Complexes of Phenanthroline Bases for Cellular Imaging and Photocytotoxicity in HeLa Cells

A Thermodynamic Study of New Designed Complex of Ethylendiamine 8-Hydroxyquinolinato Palladium(II) Chloride with Calf Thymus DNA

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