Heterogenization of homogeneous NHC-Pd-pyridine catalysts and investigation of their catalytic activities in Suzuki-Miyaura coupling reactions

Tamarindus indica seed ash extract for C-C coupling under added organics and volatile organic solvent-free conditions: a waste repurposing technique for Suzuki-Miyaura reaction

A tremendous research has been appeared on Pd-catalyzed Suzuki-Miyaura cross-coupling (SMC) during the last four decades due to its high prominence in constructing biaryl motifs of several complexes as well as simple organic compounds of high biological and commercial significance. The use of organic solid waste-derived materials for SMC in benign solvents like water/aqueous media is a very good achievement in these cases. We report in this article the usability of water extract of Tamarindus indica seeds ash (WETS) as a renewable base and reaction medium for Pd(OAc)₂-catalyzed SMC reaction at room temperature (RT). The WETS has been characterized using powder XRD, EDAX, SEM, and FTIR analysis. Furthermore, this process is highly environmentally beneficial by the waste repurposing to prominent chemical transformation along with the advantages such as ambient condition and avoids non-renewable chemicals like volatile organic solvents, ligands, promoters, and bases. Based on these merits and the quick reactions with high yields of products, this method can attain the interest of the scientific community in exploring the waste-derived ashes to significant chemical transformations. Tamarindus indica seed ash extract for C-C coupling under added organics and volatile organic solvent-free conditions: a waste repurposing technique for Suzuki-Miyaura reaction.

Vinyl functionalized 5,6-dimethylbenzimidazolium salts: Synthesis and biological activities

A series of vinyl functionalized 5,6-dimethylbenzimidazolium salts are synthesized. All compounds were fully characterized by elemental analyses, MS, ¹ H-NMR, ¹³ C-NMR, and IR spectroscopy techniques. Enzyme inhibition is a very active area of research in drug design and development. In this study, the synthesized novel benzimidazolium salts were evaluated toward the human erythrocyte carbonic anhydrase I (hCA I), and II (hCA II) isoenzymes, acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) enzymes. They demonstrated highly potent inhibition ability against hCA I with K_i values of 484.8 ± 62.6-1389.7 ± 243.2 nM, hCA II with K_i values of 298.9 ± 55.7-926.1 ± 330.0 nM, α-glycosidase with K_i values of 170.3 ± 27-760.1 ± 269 μM, AChE with K_i values of 27.1 ± 3-77.6 ± 1.7 nM, and BChE with K_i values of 21.0 ± 5-61.3 ± 15 nM. As a result, novel vinyl functionalized 5,6-dimethylbenzimidazolium salts (1a-g) exhibited effective inhibition profiles toward studied metabolic enzymes. Therefore, we believe that these results may contribute to the development of new drugs particularly to treat some global disorders including glaucoma, Alzheimer's disease, and diabetes.

Preparation, Characterization, and Catalytic Properties of Pd-Graphene Quantum Dot Catalysts

In this study, Pd-graphene quantum dot (Pd-GQD) catalysts were prepared by depositing Pd nanoparticles onto functionalized GQD surfaces, and their morphology and elemental composition were characterized using transmission electron microscopy, X-ray photoelectron spectroscopy, and Raman spectroscopy. The as-prepared Pd-GQD was subsequently employed as a catalyst for the Heck and decarboxylative cross-coupling reactions and was found to exhibit higher catalytic activity than other reference systems. The expanded substrate scope of various substituted aryl iodides further proved that the GQD is an effective support for preparing new heterogeneous catalysts with improved catalytic performances.

Preparation of poly(acrylamide‐co‐2‐acrylamido‐2‐methylpropan sulfonic acid)‐g‐Carboxymethyl cellulose/Titanium dioxide hydrogels and modeling of their swelling capacity and mechanic strength behaviors by response surface method technique

It is very important that new generation, unique, high mechanical strength, and biocompatible hydrogel composites are developed due to their potential to be used as biomaterials in the biomedical field. Modeling of the swelling capacity and mechanical strength behavior of hydrogels is a domain of steadily increasing academic and industrial importance. These behaviors are difficult to model accurately due to hydrogels show very complex behavior depending on the content. In this study, a series of poly(acrylamide‐co‐2‐acrylamido‐2‐methylpropan sulfonic acid)‐g‐carboxymethyl cellulose/TiO2 (poly(AAm‐co‐AMPS)‐g‐CMC/TiO2) superabsorbent hydrogel composites were prepared by free‐radical graft copolymerization in aqueous solution. Structural and surface morphology characterizations were conducted by using Fourier‐transform infrared spectroscopy and scanning electron microscope analysis techniques. For modeling the equilibrium swelling capacity and fracture strength behaviors of hydrogels, the composition parameters (such as mole ratio of AMPS/AAm, wt% of CMC, and wt% of TiO2) was proposed by response surface method (RSM) Design Expert‐10 software. Statistical parameters showed that the RSM model has good performance in modeling the swelling capacity and mechanic fracture strength behaviors of poly(AAm‐co‐AMPS)‐g‐CMC/TiO2 hydrogel composites. According to the RSM model results, the maximum swelling capacity and fracture strength values were calculated as 270.39 g water/g polymer and 159.23 kPa, respectively.

Palladium immobilized on functionalized hypercrosslinked polymers: a highly active and recyclable catalyst for Suzuki–Miyaura coupling reactions in water

Three palladium complexes were synthesized via an external cross-linking reaction and found to be effective heterogeneous catalysts for the Suzuki–Miyaura reaction.