Heck and oxidative boron Heck reactions employing Pd(II) supported amphiphilized polyethyleneimine‐functionalized MCM‐41 (MCM‐41@aPEI‐Pd) as an efficient and recyclable nanocatalyst

A novel nanocatalyst was developed based on covalent surface functionalization of MCM‐41 with polyethyleneimine (PEI) using [3‐(2,3‐Epoxypropoxy)propyl] trimethoxysilane (EPO) as a cross‐linker. Amine functional groups on the surface of MCM‐41 were then conjugated with iodododecane to render an amphiphilic property to the catalyst. Palladium (II) was finally immobilized onto the MCM‐41@PEI‐dodecane and the resulted MCM‐41@aPEI‐Pd nanocatalyst was characterized by FT‐IR, TEM, ICP‐AES and XPS. Our designed nanocatalyst with a distinguished core‐shell structure and Pd²⁺ ions as catalytic centers was explored as an efficient and recyclable catalyst for Heck and oxidative boron Heck coupling reactions. In Heck coupling reaction, the catalytic activity of MCM‐41@aPEI‐Pd in the presence of triethylamine as base led to very high yields and selectivity. Meanwhile, the MCM‐41@aPEI‐Pd as the first semi‐heterogeneous palladium catalyst was examined in the C‐4 regioselective arylation of coumarin via the direct C‐H activation and the moderate to excellent yields were obtained toward different functional groups. Leaching test indicated the high stability of palladium on the surface of MCM‐41@aPEI‐Pd as it could be recycled for several runs without significant loss of its catalytic activity.     

A VERSATILE METHOD FOR THE CONVERSION OF ALDOXIMES TO NITRILES USING SILICA GEL/THIONYL CHLORIDE

A simple convenient procedure for dehydration of aldoximes has been developed using silica gel/thionyl chloride in heterogeneous conditions. The method has been found to be effective for a wide range of aromatic oximes.     

Thermal performance enhancement in a miniature channel using different passive methods

Journal of Thermal Analysis and Calorimetry - In the present work, different passive methods have been numerically investigated to improve the thermal performance in a miniature channel. The heat...     

One-step Synthesis of 3,4-Dihydrobenzimidazo[2,1- b ]quinazolin-1(2 H )-ones in an Ionic Liquid

A novel class of 3,4-dihydrobenzimidazo[2,1-b]quinazolin-1(2H)-ones was synthesized in very short reaction times with good yields in the presence of 3-butyl-1-methyl imidazolium bromide as a room temperature ionic liquid at 120°C. The ionic liquid can be recycled for subsequent reactions without any loss of efficiency.     

Tuning the electronic‐optical properties of porphyrin‐like porous C24N24 fullerene with (Li3O)n = (1–5) decoration. A computational study

Using DFT methods, the electronic properties and the first hyperpolarizabilities of porphyrin‐like porous C₂₄N₂₄ fullerene decorated with (Li₃O)_{n = (1–5)} have been systematically investigated. It is found that Li₃O molecules can effectively be adsorbed over N4 cavities of C₂₄N₂₄ with high interaction energies. This interaction is found to narrow the HOMO‐LUMO gap and work function values of C₂₄N₂₄. Thus its electronic properties are strongly sensitive to interaction with the Li₃O molecules. Indeed, compared with the sole parent C₂₄N₂₄ fullerene, (Li₃O)_{n = (1–5)}@C₂₄N₂₄ possess large first hyperpolarizabilities (β₀ ). Obviously, the Li₃O superalkali chemisorbed over C₂₄N₂₄ fullerene exhibit not only excellent stability but also large first hyperpolarizability. Therefore, they are expected to be potential innovative candidates for excellent electro‐optical materials.     

Erratum to: Top local cohomology modules and Gorenstein injectivity with respect to a semidualizing module

This note makes a correction to the paper “Top local cohomology modules and Gorenstein injectivity with respect to a semidualizing module”.