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

Abstract

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)

Synthesis and the Effect of a Peripheral N‐Arylcarbazole Moiety on theAcid‐Base and DNA Binding Properties of a Novel RuII Complex

“…hydroxy, carboxyl and amino groups may respond sensitively to the changes in environmental pH, providing a chance to make pH sensing or switching molecular devices, [3] and to greatly modulate their biological functionalities. [4] The ruthenium(ii) complexes containing imidazole groups have been well studied with respect to their interaction with DNA [5][6][7][8] or reversible acid-base interconver-ground-and excited-state ionization constants were derived. The results indicated that the complex intercalatively bound to the DNA, with an intrinsic binding constant of (8. sion.…”

Binding of an Oxo‐Bridged Dinuclear Iron(III) Complex{[Fe(phen)(H2O)3]2O}(SO4)2 to DNA and Its Recognition of Single‐ and Double‐Stranded DNA As Determined by Electrochemical Studies

“…The hydrogen atoms were located by difference synthesis and refined isotropically. The final conventional R indices were R(F) = 0.0601 and wR(F 2 ) = 0.1496 for 2391 reflections I Ͼ 2σ(I) with weighting scheme, w = 1/[σ 2 (F o 2 ) + (0.0905P) 2 ], where P = (F o 2 + 2F c 2 )/3. The molecular graphics were plotted using SHELXTL.…”

“…This is similar to the DNA cleavage mediated by the Fe-bleomycin complex and its mimetic compounds. [23] Additionally, Xu et al [24] have investigated the interaction of DNA with a diiron complex Fe 2 (DTPB)(µ-O)(µ-Ac)-Cl(BF 4 ) 2 [DTPB = 1,1,4,7,7-penta(2Ј-benzimidazol-2-ylmethyl)triazaheptane, Ac = acetate] by spectroscopic methods. In addition, the hydrolytic cleavage of the supercoiled and linear DNA by the diiron complex was supported by evidence from anaerobic reactions, free-radical quenching, high-performance liquid chromatography experiments, enzymatic manipulation, footprinting analysis, and so forth.…”

“…Studies on the interaction between DNA and small molecules are central to probing the accurate local structures of DNA, [1][2][3][4][5] and to understanding the natural DNA-mediated biological mechanisms. [6] The fields of applied pharmacology, novel drug design [7][8] and chemotherapy [9] also emphasize the interactions of small molecules with DNA.…”

A rational synthesis of a novel imidazo[4,5-f][1,10]phenanthroline templated Schiff base: Characterization, photoluminescence and DFT/TD-DFT study

“…They constitute versatile components of metallomesogens or behave as mesogenic phase without metal component in the design of liquid crystals [13][14][15][16]. In addition, they play key roles in spectroscopic biosensing of nucleic acids owing to site-selective and adaptive binding to DNA in intercalative mode and in the development of unique chemotherapeutics where they impact on the functions of DNA within cancerous cells [17][18][19][20][21][22][23][24][25][26][27]. Therefore, imp derivatives seem to attract much more interest with many attempts to synthesize and design new materials with the above-mentioned properties.…”