Spectroscopic and Molecular Modeling Based Approaches to Study on the Binding Behavior of DNA with a Copper (II) Complex

Blocking the division of tumor cells by small-molecules is currently of great interest for the design of new antitumor drugs. The interaction of a new metal complex with DNA was investigated through several techniques. Absorption spectroscopy and gel electrophoresis studies on the interaction of the Cu-complex of (2a-4mpyH)₂ [Cu(pyzdc)₂ (H₂O)₂].6 H₂O with DNA have shown that this complex can bind to CT-DNA with binding constant 3.99?×?10⁵ M^?1. The cyclic voltammetry (CV) responses of the metal complex in the presence of CT-DNA have shown that the metal complex can bind to CT-DNA through partial intercalation mode and this is consistent with molecular docking analysis, quenching process and thermal denaturation experiments. The cytotoxicity of this complex has been evaluated by MTT assay. The results of cell viability assay on DU145 cell line revealed that the metal complex had cytotoxic effects.     

Nilpotent and invertible values in semiprime rings with generalized derivations

Let R be a semiprime ring and F be a generalized derivation of R and n??? 1 a fixed integer. In this paper we prove the following: (1) If (F(xy) ? yx) ⁿ is either zero or invertible for all ${x,y\in R}$ , then there exists a division ring D such that either R?=?D or R?=?M ₂(D), the 2?× 2 matrix ring. (2) If R is a prime ring and I is a nonzero right ideal of R such that (F(xy) ? yx) ⁿ ?=?0 for all ${x,y \in I}$ , then [I, I]I?=?0, F(x)?=?ax?+?xb for ${a,b\in R}$ and there exist ${\alpha, \beta \in C}$ , the extended centroid of R, such that (a ? ??)I?=?0 and (b ? ??)I?=?0, moreover ((a?+?b)x ? x)I?=?0 for all ${x\in I}$ .     

Synthesis,characterization, and biological evaluation of new polyester containing Schiff base metal complexes

The production of new biocidal polyester Schiff base metal complexes [PESB–M(II)] via polycondensation reaction between chelated Schiff base diol and adipoyl chloride is reported. The resulting polyesters were characterized by physico-chemical and spectroscopic methods. The analytical data of all the synthesized polyesters were found to be in good agreement with 1:1 molar ratio of chelated Schiff base diol to adipoyl chloride. Thermogravimetric analyses of synthesized polyesters were studied by TG in nitrogen atmosphere up to 1073 K and results indicate that Cu(II) polyester complex exhibited better heat resistant properties than the other polyesters complexes. Magnetic moment and UV–visible spectra were examined to explain the structure of all the polyesters which reveled that Mn(II), Co(II), Ni(II) have octahedral geometry while Cu(II) possess a distorted octahedral geometry. These newly developed polyesters were also tested for their antibacterial activity against several bacteria and fungi. Among all the tested compounds PESB–Cu(II) possess the highest bactericidal and fungicidal activity.     

Structure of clean and hydrated α-Al2O3 (1102) surfaces: implication on surface charge

Periodic DFT calculations coupled to a first-principle thermodynamic approach have allowed us to establish a surface phase diagram for the different terminations of the α-Al(2)O(3) (1102) surface in various temperature and water pressure conditions. Theoretical results are compared with previous experimental data from the literature. Under a wide range of temperature and water pressure (including ambient conditions) the most stable surface (denoted C2_1H(2)O in this work) is terminated with singly coordinated hydroxyls on four-fold coordinated aluminium (Al(4C)-μ(1)-OH) while most existing surface models are only considering six-fold coordinated surface Al atoms as in the bulk structure of alumina. The presence of more acidic Al(4C)-μ(1)-OH sites helps explain the low Point of Zero Charge (PZC) (between 5 and 6) determined from the onset of Mo oxoanions adsorption on (1102) single crystal wafers. It is also postulated that another termination (corresponding to the hydration of the non-polar, stoichiometric surface, stable in dehydrated conditions) may be observed in aqueous solution depending on the surface preparation conditions.     

Solution Thermodynamics of Piroxicam in some Ethanol + Water Mixtures and Correlation with the Jouyban–Acree Model

The solubility of piroxicam (PIR) in several ethanol + water mixtures was determined at five temperatures from 293.15 to 313.15 K. The thermodynamic functions; Gibbs energy, enthalpy, and entropy of solution and of mixing were obtained from these solubility data and the drug properties of fusion by using the van’t Hoff and Gibbs equations. The greatest solubility value was obtained in pure ethanol. A non-linear enthalpy–entropy relationship was observed from a plot of enthalpy versus Gibbs energy of solution. Accordingly, the driving mechanism for PIR solubility in water-rich mixtures is the entropy, probably due to water-structure loss around the drug’s non-polar moieties by ethanol, whereas, in ethanol-rich mixtures the driving mechanism is the enthalpy, probably due to better PIR solvation by the co-solvent molecules. The solubilities and the derived thermodynamic properties in mixed solvents were correlated using the Jouyban–Acree model.     

A simple one-pot 2-step N-1-alkylation of indoles with α-iminoketones toward the expeditious 3-step synthesis of N-1-quinoxaline-indoles

A straightforward procedure for the preparation of N-quinoxaline-indoles is presented. A base-catalyzed one-pot addition of indoles to a preformed α-iminoketone proceeds on the N-1 indole and the subsequent adduct undergoes an acid-mediated deprotection of an internal amino nucleophile, intramolecular cyclization, and final oxidation generating N-1-quinoxaline-indoles in good yield.     

Interaction of Clofazimine with Divalent Metal Ions: A Fluorescence Quenching Study

The interaction of clofazimine (CFZ) with divalent metal cations was studied by measuring fluorescence quenching spectra, synchronous fluorescence spectra and ultraviolet spectra. The fluorescence quenching spectra of CFZ in the presence of metal ions showed that metal ions quenched the fluorescence of CFZ. The quenching constants were determined using the Stern–Volmer equation. The binding constants (log K) and binding site were obtained. The thermodynamic parameters obtained in this study revealed that the interaction between CFZ and metal ions was mainly driven by a hydrophobic force. The conformational changes of CFZ were investigated by synchronous spectrum studies.     

Novel Photochemical Synthesis of Spiro-1,2,6,8,9 Pentaza-4-thia(4,4)nonane via Rearrangement of Aliphatic Arylazo Compounds

Irradiation of N-phenyl-2-phenylazo-3-oxo-3-[(4-phenyl-5-aryl)-1,2,4-triazol-3-yl)thio]butanamides 4 _a–c gave the corresponding title spiro compounds 5 _a–c as end products via tandem rearrangement and cyclization of 4 _a–c in their excited states.     

Synthesis of Symmetric Bridged Bis-Pyrazolone Based Metal Complex Acid Dyes and their Applications on Leather

Our present investigation aims at the synthesis and application of new, symmetric bridged bis-pyrazolone based acid dyes. The bis-pyrazolone compounds were accomplished from bis- hydrazine of 4,4′-Diaminostilbene-2,2′-disulfonic acid and ethyl acetoacetate. The bis-pyrazolones have been coupled with diazonium salts of o-hydroxyl aromatic amines which resulted in ligand dyes. The intermediate ligand dyes were treated with 3d transition metals to achieve the targeted metal complex acid dyes. The structures of investigated compounds were confirmed with the help of spectroscopic techniques. Dyes were applied on leather and their application parameters including their light fastness, wash fastness and rubbing fastness were determined.

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Graphical Abstract Symmetric brymmetric Bridged bis-Pyrazolone based Metal Complex Acid