Photodegradation of Naproxen Using Ag/AgCl–PANI Composite under Solar Light: Transformation Product and Reaction Kinetics

Kinetics and Catalysis - The photocatalytic degradation of organic micropollutant naproxen (NPX) was evaluated under solar light using Ag/AgCl–polyaniline (Ag/AgCl–PANI) photocatalyst....     

Bioassay Guided Isolation and Identification of a Cytotoxic Compound from Azadirachta indica Leaves

This study aimed to investigate the structural features of the isolated flavonol glycoside, which might behave as a cytotoxic compound. The hexane, chloroform, ethyl acetate, and aqueous fractions of an 80% methanol solution of Neem (Azadirachta indica) (Family: Meliaceae) leaves were subjected to a cytotoxicity bioassay against brine shrimp, Artemia salina. The ethyl acetate fraction exhibited the highest cytotoxic effect, supported by the lowest lethal concentration, a LC₅₀ value of 1.35±0.40 ppm. A compound, Quercetin 3‐O‐β‐D‐glucopyranoside, was isolated from the most toxic fraction of the ethyl acetate via preparative liquid chromatography and then identified via ultraviolet‐visible (UV‐Vis), infrared (IR), mass spectrum (MS) and nuclear magnetic resonance (NMR) analyses. The compound was further confirmed by physical state, color, solubility, and melting point determination. The cytotoxic results suggest that the leaf ethyl acetate fraction consists of toxic compounds, which point towards the isolation of Quercetin 3‐O‐β‐D‐glucopyranoside.     

Polynuclear 3d complexes based on potentially tetra-anionic heptadentate ligands including amido,amino and phenoxo donors: Synthesis,crystal structure and magnetic properties

The synthesis and characterization of new dinuclear Mn^III and tetranuclear Cu^II complexes, [HL¹Mn(DMSO)]₂ (1) and [H₂L²Cu₂(MeO)₂]₂ (2), are reported (H₄L¹ = 2-hydroxy-N-[2-({2-[(2-hydroxybenzoyl)amino]ethyl}amino)ethyl]benzamide and H₄L² = 2-hydroxy-N-[3-({3-[(2-hydroxybenzoyl)amino]propyl}(methyl)amino)propyl]benzamide). Single crystal X-ray structures have been determined for 1 and 2. In 1 only one of the two amide functions of H₄L¹ is deprotonated in addition to the phenol ones, while in 2 all the amide functions of H₄L² are protonated and none of the potential nitrogen donors (amide and amine) is involved in the coordination to copper. HL¹ and H₂L² do not play the role of compartmental ligands and do not wrap around one Mn and one Cu ion, respectively, but embrace two metal centers yielding, with the respective assistance of auxiliary DMSO and methoxo ligands, dinuclear manganese and tetranuclear copper complexes, respectively. 1 includes two well isolated Mn^III ions (Mn?Mn′ = 7.33 Å) that do not interact magnetically. The intermolecular Mn?Mn″ distance along the 1D chains (10.17 Å) is also too large to allow extended magnetic interactions. The pairwise magnetic interactions between the copper(II) ions in the tetranuclear complex 2 are so large that the χ_MT product is already equal to zero at room temperature, implying that the antiferromagnetic interaction is around −1000 cm⁻¹, as observed previously for di-μ-hydroxo–dicopper complexes.     

Topological features of both electron density and electrostatic potential in the bis(thiosemicarbazide)zinc(II) dinitrate complex

The experimental electron density of the bis(thiosemicarbazide)zinc(II) dinitrate complex, [Zn(CH5N3S)2](NO3)2,was studied. The Hansen-Coppens multipole model was used to extract the electron density from high-resolution X-ray diffraction data collected at 100 K. Careful strategies were designed for the electron density refinements regarding the charge transfer between the anionic and the cationic parts of the complex. Particular attention was also paid to the treatment of the electron density of the zinc atom interacting with two thiosemicarbazide ligands in a tetrahedral coordination. Nevertheless, the filled 3d valence shell of Zn was found unperturbed, and only the 4s shell was engaged in the metal-ligand interaction. Topological properties of both electron density and electrostatic potential, including kinetic and potential energy densities, and atomic charges were reported to quantify a metal-ligand complex with particular Zn-S and Zn-N bonds and hydrogen-bonding features. Chemical activities were screened through the molecular surface on which the three-dimensional electrostatic potential function was projected. The experimental results were compared to those obtained from gas-phase quantum calculations, and a good agreement was reached between these two approaches. Finally, among other electrostatic potential critical points, the values at the maxima corresponding to the nuclear sites were used as indices of the hydrogen-bonding capacity of the thiosemicarbazide ligand.     

Sémantique de type Kripke d'un système logique basé sur un ensemble ordonné fini

In order to modelize the reasoning of intelligent agents represented by a poset T, H. Rasiowa introduced logic systems called “Approximation Logics”. In these systems the use of a set of constants constitutes a fundamental tool. We have introduced in [8] a logic system called without this kind of constants but limited to the case that T is a finite poset. We have proved a completeness result for this system w.r.t. an algebraic semantics. We introduce in this paper a Kripke‐style semantics for a subsystem of for which there existes a deduction theorem. The set of “possible worldsr is enriched by a family of functions indexed by the elements of T and satisfying some conditions. We prove a completeness result for system with respect to this Kripke semantics and define a finite Kripke structure that characterizes the propositional fragment of logic . We introduce a reational semantics (found by E. Orlowska) which has the advantage to allow an interpretation of the propositionnal logic using only binary relations. We treat also the computational complexity of the satisfiability problem of the propositional fragment of logic .     

Amineptine Plastic Membrane Electrode Based on its Ion Associate with Tetraphenylborate and Phosphomolybdic Acid

New amineptine hydrochloride (Am-Cl) ion-selective electrodes (conventional type) based on amineptinium-tetraphenylborate (I) and amineptinium-phosphomolybdate (II) were prepared. The electrodes exhibited mean slopes of calibration graphs of 57.9?mV and 53.8?mV per decade of (Am-Cl) concentration at 25?°C for electrodes (I) and (II), respectively. The electrodes can be used within the concentration range 3.16×10^?5?10^?2?M (Am-Cl) at a pH range of 2.0–3.9 for both electrodes. The standard electrode potentials were determined at different temperatures and used to calculate the isothermal coefficients of the electrodes, which were 0.00172?V?°C^?1 and 0.00091 V?°C^?1 for (I) and (II) electrodes, respectively. The electrodes showed a very good selectivity for (Am-Cl) with respect to a number of inorganic cations and sugars. The standard addition method is successfully applied to determine (Am-Cl) in pure solutions and in amineptine-containing tablets.     

The Synthesis of Warfarin Using a Reconfigurable-Reactor Platform Integrated to a Multiple-Variable Optimization Tool

Optimization of the asymmetric synthesis of warfarin, an important anticoagulant, has been evaluated using a reconfigurable reaction platform capable of performing batch, continuous flow, and plug-flow synthesis. Further, this platform has been integrated with a novel, multidimensional, multiple variable analysis tool that can evaluate multiple critical quality attributes (CQA), percent conversion and enantiomeric excess in this case, from a single injection that is repeatedly recycled in a closed loop of chromatography columns, a detector and a heart-cut valve. Further, the new, integrated analysis system also facilitates validation of each QA, providing a high-level of confidence in analytical measurements, which are obtained without operator intervention.