Search results for " metal complex"

The Interaction of Metal Complexes with G-quadruplex DNA

Un approccio computazionale è stato proposto per lo studio dell’interazione di complessi metallici di basi di Schiff con DNA. Nel capitolo 2, è stato investigato il meccanismo di azione di complessi di Nichel(II), Rame(II) e Zinco(II) con B e G-quadruplex DNA. Il G-quadruplex è una conformazione non canonica adottata da particolari sequenze ricche in guanina. Recentemente, è stata dimostrata la sua esistenza in cellule umane, in regioni telomeriche e non telomeriche, ed è stato proposto come un possibile target per una nuova categoria di agenti antineoplastici. I capitoli successivi sono basati su dati raccolti durante due periodi di ricerca all’estero. Nel capitolo 3, basato sugli studi es…

Studio dell'interazione di DNA con complessi di metalli di transizione

2014

Ruthenium-arene complexes bearing naphthyl-substituted 1,3-dioxoindan-2-carboxamides ligands for G-quadruplex DNA recognition.

2019

Quadruplex nucleic acids – DNA/RNA secondary structures formed in guanine rich sequences – proved to have key roles in the biology of cancers and, as such, in recent years they emerged as promising targets for small molecules. Many reports demonstrated that metal complexes can effectively stabilize quadruplex structures, promoting telomerase inhibition, downregulation of the expression of cancer-related genes and ultimately cancer cell death. Although extensively explored as anticancer agents, studies on the ability of ruthenium arene complexes to interact with quadruplex nucleic acids are surprisingly almost unknown. Herein, we report on the synthesis and characterization of four novel Ru(…

Salphen metal complexes as potential anticancer agents: interaction profile and selectivity studies toward the three G-quadruplex units in the KIT pr…

2022

DNA G-rich sequences can organize in four-stranded structures called G-quadruplexes (G4s). These motifs are enriched in significant sites within the human genomes, including telomeres and promoters of cancer related genes. For instance, KIT proto-oncogene promoter, associated with diverse cancers, contains three adjacent G4 units, namely Kit2, SP, and Kitt. Aiming at finding new and selective G-quadruplex binders, we have synthesized and characterized five non-charged metal complexes of Pt(II), Pd(II), Ni(II), Cu(II) and Zn(II) of a chlorine substituted Salphen ligand. The crystal structure of the Pt(II) and Pd(II) complexes was determined by XRPD. FRET measurements indicated that Pt(II) an…

Weak alkali and alkaline earth metal complexes of low molecular weight ligands in aqueous solution

2008

This work is aimed at reviewing the chemical literature dealing with thermodynamic aspects of the weak complex formation (species with log K values less than about 3) between alkali and alkaline earth metal ions with low molecular weight inorganic and organic ligands in aqueous solution. The following ligands (up to hexavalent anions) were examined in detail: (i) hydroxide, chloride, sulfate, carbonate and phosphate as inorganic, and (ii) carboxylates, amines, amino acids, complexones and nucleotides as organic ligands. The paper also identifies the main reasons responsible for the dispersion of the stability data on ion pairs in the literature. When possible, the trend of stability for the…

Flexible light-emitting electrochemical cells with single-walled carbon nanotube anodes

2016

Abstract In this work, we demonstrate flexible solution processed light emitting electrochemical cells (LECs) which use single-walled carbon nanotubes (SWCNTs) films as the substrate. The SWCNTs were synthesized by an integrated aerosol method and dry-transferred on the plastic substrates at room temperature. The addition of a screen printed poly (3,4-ethylene dioxythiophene) doped with poly (styrene sulfonate) (PEDOT:PSS) film onto the nanostructured electrode further homogenizes the surface and enlarges the work function, enhancing the hole injection into the active layer. By using an efficient phosphorescent ionic transition metal complex (iTMC) as the active material, efficacies up to 9…

The solution behavior of dopamine in the presence of mono and divalent cations: A thermodynamic investigation in different experimental conditions

2021

The interactions of dopamine [2-(3,4-Dihydroxyphenyl)ethylamine, (Dop-)] with methylmercury(II) (CH3Hg+), magnesium(II), calcium(II), and tin(II) were studied in NaCl(aq) at different ionic strengths and temperatures. Different speciation models were obtained, mainly characterized by mononuclear species. Only for Sn2+ we observed the formation of binuclear complexes (M2L2 and M2LOH (charge omitted for simplicity)

Synthesis, characterization, cellular uptake and interaction with native DNA of a bis(pyridyl)-1,2,4-oxadiazole copper(II) complex

2010

The copper(II) complex of 3,5-bis(2'-pyridyl)-1,2,4-oxadiazole was synthesized and characterized. X-Ray crystallography revealed that the complex consists of a discrete [Cu(3,5-bis(2'-pyridyl)-1,2,4-oxadiazole)(2)(H(2)O)(2)](2+) cation and two ClO(4)(-) anions. The Cu(II) coordination sphere has a distorted octahedral geometry and each ligand chelates the copper ion through the N(4) nitrogen of the oxadiazole ring and the nitrogen of one pyridine moiety. The coordinated water molecules are in cis position and each of them is H-bonded to the 5-pyridyl nitrogen of the oxadiazole ligand and to an oxygen of the perchlorate anion. Biological assays showed that, despite the free ligand not being …

The Impact of Humic Substances as Remediation Agents to the Speciation Forms of Metals in Soil

2013

Abstract Humic substances (HS) are the most widespread group of organic substances in natural environment and have high stability. The main terrestrial reserves are found in the form of naturally occurring ore, peat or lignite. The aim of this paper is to study possibilities to use HS as agents for remediation of contaminated with heavy metals soil and impacts of HS of metal speciation forms in it. It has been proved that HS are able to bind to metal ions and change their speciation forms in soils. The ability to form complexes with metal ions depends on the type of soil, type of metal, as well as concentrations of HS in soil. The study was carried out in experimental conditions and analyti…

Ultrafast Relaxation Dynamics of Osmium−Polypyridine Complexes in Solution

2013

We present steady-state absorption and emission spectroscopy and femtosecond broadband photoluminescence up-conversion spectroscopy studies of the electronic relaxation of Os(dmbp)(3) (Os1) and Os(bpy)(2)(dpp) (Os2) in ethanol, where dmbp is 4,4'-dimethyl-2,2'-biypridine, bpy is 2,2'-biypridine, and dpp is 2,3-dipyridyl pyrazine. In both cases, the steady-state phosphorescence is due to the lowest (MLCT)-M-3 state, whose quantum yield we estimate to be <= 5.0 x 10(-3). For Os1, the steady-state phosphorescence lifetime is 25 ns. In both complexes, the photoluminescence excitation spectra map the absorption spectrum, pointing to an excitation wavelength-independent quantum yield. The ultrafa…