Well-defined PEPPSI-themed palladium–NHC complexes: synthesis,and catalytic application in the direct arylation of heteroarenes

In this study, a series of benzimidazolium salts were synthesized as unsymmetrical N-heterocyclic carbene (NHC) precursors. Benzimidazolium salts were used for synthesis of the PEPPSI (pyridine enhanced precatalyst preparation stabilization and initiation)-themed, six new Pd-complexes with the general formula [PdX₂(NHC)(pyridine)]. The structures of all compounds were characterized by various spectroscopic techniques such as ¹H NMR, ¹³C NMR and FT-IR. The more detailed structural characterization of four of the complexes was determined by single-crystal X-ray diffraction study. The catalytic activities of all Pd-complexes were evaluated in the direct arylation of the 2-acetylfuran and 2-acetylthiophene with aryl bromides in the presence of 1 mol% catalyst loading.     

Synthesis of water soluble Pd-Piperidoimidazolin-2-ylidene complexes and their catalytic activities in neat water

Through the strategy of water soluble N-heterocyclic carbene (NHC) ligand, Pd-catalyzed reactions were developed in aqueous media. Therefore, four new piperidoimidazolinium salts ( 1a-d ) consisting of sulfonate ( a ), esther ( b , c ) and carboxylic acid ( d ) functionalities and their water-soluble Pd-NHC complexes ( 2a - d ) were synthesized. The new compounds were characterized by elemental analysis, FTIR, TGA, UV–vis and NMR spectroscopy. The catalytic activities of water soluble Pd-NHC complexes ( 2a - d ) were investigated using the Suzuki-Miyaura (S-M) reaction and the reduction of nitroarenes. We found that the water-soluble polar or ionic groups on piperidoimidazolin-2-ylidine had an effect on the catalytic activity. The water-soluble catalyst can be recycled efficiently and reused six times with only a very slight loss of catalytic activity.     

Prediction of the deswelling behaviors of pH- and temperature-responsive poly(NIPAAm-co-AAc) IPN hydrogel by artificial intelligence techniques

Research on Chemical Intermediates - One of the most important fields of interest in respect of stimuli-responsive hydrogels is modeling and simulation of their deswelling behavior. The problem...     

A convenient approach directly from triglycerides toward the producing of thia-wax esters as bio- and chemical raw materials

Research on Chemical Intermediates - Practical and efficient method has been developed for the preparation of novel sulfur-containing esters from triglycerides as potential important industrial and...     

Simultaneous Determination of Thiocolchicoside and Diclofenac Diethyl Ammonium in Topical Gel Formulation by Square Wave Voltammetric Method

Russian Journal of Electrochemistry - A rapid, simple, sensitive, precise and specific square wave voltammetric method was developed for the simultaneous determination of Thiocolchicoside (TC) and...     

Seasonal and annual performance analysis of PCM-integrated building brick under the climatic conditions of Marmara region

Journal of Thermal Analysis and Calorimetry - In this work, thermal performance of a conventional brick incorporating phase change material (PCM) is studied. The influence of brick containing PCM...     

Cyclic Strain Heterogeneity and Damage Formation in Rolled Magnesium Via In Situ Microscopic Image Correlation

Experimental Mechanics - Inherently tied to the complexity of their deformation mechanisms, Magnesium alloys show a high propensity for strain localization at multiple length-scales. Understanding...     

Aerodynamic and energy-efficiency-based assessment of plasma actuator's position on a NACA0015 airfoil

In recent years, there has been an increase in the number of research papers on plasma and its use in active flow control applications. The main objective of this study is to assess the plasma actuator's position on a NACA0015 airfoil in terms of aerodynamic forces. In addition, optimization of the plasma actuator's position and its configuration are studied in order to identify the optimum configuration for improvement in lift coefficient. The experiments are conducted in an open-suction-type wind tunnel at Reynolds numbers of 48,000, 75,000, and 100,000. The plasma actuators are mounted on various positions (x/C) starting from the leading edge to trailing edge of the airfoil. The experimental results on aerodynamic force measurement are presented to illustrate the increasing lift effect of the generated plasma. It is also shown that the plasma actuators used as an active flow control device appears to shift the stall angle of the airfoil. The results of the experimental study suggest that the energy efficiency of airborne systems can be improved with the use of plasma actuators due to its increasing lift coefficient effect. This result becomes a vital finding considering that the same flight can be achieved with less fuel and less amount of environmental pollution for the same distance of journey. It is also worth mentioning that increasing lift effect would mean taking off from a shorter runway or allowing the airborne vehicle with the ability to fly with additional payload.     

The choice property in tame expansions of o-minimal structures

We establish the choice property, a weak analogue of definable choice, for certain tame expansions of o-minimal structures. Most noteworthily, this property holds for dense pairs of real closed fields, as well as for expansions of o-minimal structures by a dense independent set.