Ru(II) complexes bearing tertiary phosphine ligands: a novel and efficient homogeneous catalyst for one‐pot synthesis of dihydropyrano[3,2‐c]chromene and tetrahydrobenzo[b]pyran derivatives

A number of ruthenium complexes were prepared and their catalytic activities in three‐component one‐pot condensation of aldehydes, malononitrile and 4‐hydroxycoumarin or dimedone was considered to afford dihydropyrano[3,2‐c]chromenes and tetrahydrobenzo[b]pyran derivatives under optimum reaction conditions. We found that a catalytic amount of RuBr₂(PPh₃)₄ efficiently promotes the reaction in a short time (3–15 min) and with high yield (75–88%). Copyright © 2012 John Wiley & Sons, Ltd.     

Energy-related carbon dioxide emission forecasting of four European countries by employing data-driven methods

Journal of Thermal Analysis and Calorimetry - Carbon dioxide emission of countries is deeply dependent on the energy system. Share of different energy resources in primary energy consumption of the...     

Photocatalytic Degradation of Antibiotic Norfloxacin Aqueous Solution by Ce/Bi2WO6: Optimization and Simulation of Process by RSM

Russian Journal of Applied Chemistry - This study evaluated a removal efficiency of NLFX from aqueous solutions using a photocatalytic process. In this study, Bi2WO6 were synthesized by microwave...     

An efficient enzymatic method for the separation of stereoisomeric cis and trans-glycidic esters synthesised via Darzen's condensation reactions

Pig's liver esterase (PLE) was used efficiently in phosphate buffer for the separation of stereoisomeric mixtures of cis/trans-ethyl arylglycidates, produced via Darzen's condensation reactions.     

A green and practical method for the synthesis of novel pyrano[2,3-<Emphasis Type="Italic">c</Emphasis>]pyrazoles and <Emphasis Type="Italic">bis</Emphasis>-pyrano[2,3-<Emphasis Type="Italic">c</Emphasis>]pyrazoles using sulfonic acid-functionalized ionic liquid

An efficient and practical protocol was developed for the synthesis of novel pyrano[2,3-c]pyrazoles and bis-pyrano[2,3-c]pyrazoles by one-pot four-component reaction of arylaldehyde, ethyl acetoacetate, hydrazine hydrate and dimethyl malonate using SO₃H-functionalized ionic liquid [DMBSI]HSO₄ as a potential green catalyst under solvent-free condition. The method presented is mild, environmentally friendly, inexpensive and functionality tolerant and produces the desired pyranopyrazoles in short reaction times (17–24 min) and excellent yields (85–95%). In addition, the catalyst can be reused at least ten times without almost any change in its catalytic activity.     

Evaluating the Free Energies of Solvation and Electronic Structures of Lithium‐Ion Battery Electrolytes

Adaptive biasing force molecular dynamics simulations and density functional theory calculations were performed to understand the interaction of Li⁺ with pure carbonates and ethylene carbonate (EC)‐based binary mixtures. The most favorable Li carbonate cluster configurations obtained from molecular dynamics simulations were subjected to detailed structural and thermochemistry calculations on the basis of the M06‐2X/6‐311++G(d,p) level of theory. We report the ranking of these electrolytes on the basis of the free energies of Li‐ion solvation in carbonates and EC‐based mixtures. A strong local tetrahedral order involving four carbonates around the Li⁺ was seen in the first solvation shell. Thermochemistry calculations revealed that the enthalpy of solvation and the Gibbs free energy of solvation of the Li⁺ ion with carbonates are negative and suggested the ion–carbonate complexation process to be exothermic and spontaneous. Natural bond orbital analysis indicated that Li⁺ interacts with the lone pairs of electrons on the carbonyl oxygen atom in the primary solvation sphere. These interactions lead to an increase in the carbonyl (C=O) bond lengths, as evidenced by a redshift in the vibrational frequencies [ν(C=O)] and a decrease in the electron density values at the C=O bond critical points in the primary solvation sphere. Quantum theory of atoms in molecules, localized molecular orbital energy decomposition analysis (LMO‐EDA), and noncovalent interaction plots revealed the electrostatic nature of the Li⁺ ion interactions with the carbonyl oxygen atoms in these complexes. On the basis of LMO‐EDA, the strongest attractive interaction in these complexes was found to be the electrostatic interaction followed by polarization, dispersion, and exchange interactions. Overall, our calculations predicted EC and a binary mixture of EC/dimethyl carbonate to be appropriate electrolytes for Li‐ion batteries, which complies with experiments and other theoretical results.     

An efficient one‐pot synthesis of pyridazinones and phthalazinones using HY‐zeolite

The first one‐pot synthesis of pyridazinones and phthalazinones from arenes, cyclic anhydrides, and ArNHNH₂ in the presence of efficient recyclable heterogeneous catalyst, HY‐zeolite, in high yield and short reaction time is reported. J. Heterocyclic Chem., (2011).     

Cover Picture: Synthesis and Reactivity of Functionalized Binary and Ternary Thiometallate Complexes [(RT)4S6], [(RSn)3S4]2−, [(RT)2(CuPPh3)6S6], and [(RSn)6(OMe)6Cu2S6]4− (R=C2H4COOH,CMe2CH2COMe; T=Ge,Sn) (Chem. Eur. J. 27/2009)

Proof‐of‐principle is reported for a directed functionalization and derivatization of chalcogenidometallate cages with respect to the formation of hybrid compounds containing (M)/T/E semi‐conductor nodes (M=Cu; T=Ge, Sn; E=S). In their Full Paper on page 6595 ff. , S. Dehnen et al. show how it is possible to generate functionalized ternary CuSnS or CuGeS clusters and to transfer COMe ligands into CR(N–NH₂) or CR(N–NHPh) terminal groups by reaction of a series of novel, functionalized thiometallate cages [(RT)_nS_m] (n/m=4/6, 3/4), the R ligands of which are terminated by COO(H) or COMe.

     

Design of an Imipramine‐Selective Electrode Based on an Ion‐Pair and its Application to Pharmaceutical Analysis

Ion‐selective electrodes play an important role in pharmaceutical analysis due to their simplicity, rapidity and accuracy over some other analytical methods. This research introduces the design of an ion‐pair of imipramine‐tetraphenyl borate (IMP‐TPB) based PVC membrane sensor for IMP hydrochloride determination. Effect of the membrane composition, the pH influence and the effect of lipophilic anionic additives on the response characteristics of the electrode were investigated. After a series of experiments, the best electrode performance was accomplished with a membrane composition of 30% PVC, 63% DBP, 5% (IMP‐TPB) and 2% (NaTPB). This electrode illustrated a fast (15 s), stable and Nernstian response across a relatively wide IMP hydrochloride concentration range (10^?5 to 10^?5 M), in the pH range of (3.0–8.0), and it can be used for at least two months without any measurable change in sensitivity. Additionally, the interference between IMP and several drugs and common inorganic anions was negligible as shown by the potentiometric selectivity coefficient data. The membrane sensor was successfully applied to the determination of IMP in tablets and human urine samples, and very good recovery results were obtained.     

A numerical scheme for a class of nonlinear Fredholm integral equations of the second kind

In this paper an iterative approach for obtaining approximate solutions for a class of nonlinear Fredholm integral equations of the second kind is proposed. The approach contains two steps: at the first one, we define a discretized form of the integral equation and prove that by considering some conditions on the kernel of the integral equation, solution of the discretized form converges to the exact solution of the problem. Following that, in the next step, solution of the discretized form is approximated by an iterative approach. We finally on some examples show the efficiency of the proposed approach.