Synthesis and characterization of nanocatalyst Cu2+/mesoporous carbon for amidation reactions of alcohols.

In this research, mesoporous carbon (MC) with high efficiency (0.65 g yield from 1.0 g MCM-41 and 1.25 g sucrose) was successfully prepared by adding carbon precursor (sucrose) in a single step with ultrasonic waves, which reduces time and energy cost. Then, the Cu2+/Mesoporous carbon nanocatalyst (Cu2+/MC) was synthesized by adding Cu(NO3)2 in a single step and applied as a catalyst in amidation reactions of alcohols. Also, Cu2+/MC was characterized using different spectroscopic methods and techniques, including Fourier transform infrared spectroscopy (FT-IR), Field Emission Scanning Electron Microscopy (FE-SEM), N2 adsorption analysis (BET), X-ray diffraction analysis (XRD), Energy Dispersive X-ray (EDX), and Thermogravimetric Analysis (TGA). Moreover, to show the catalytic merits of Cu2+/MC, various primary and secondary amines and ammonium salts were applied in the amidation of alcohols. Easy synthesis method, recyclability, excellent yields (80-93%), and simple work-up are some noticeable strengths of using Cu2+/MC as a catalyst in this reaction.

Copper(II)-ß-cyclodextrin immobilized on graphitic carbon nitride nanosheets as a highly effective catalyst for tandem oxidative amidation of benzylic alcohols.

In this study, an efficient catalyst based on graphitic carbon nitride nanosheets (CN) and copper(II) supported ß-cyclodextrin (ß-CD/Cu(II)) was synthesized and used for tandem oxidative amidation of benzylic alcohols. In this regard, CN was functionalized by ß-CD/Cu(II) via 1,3-dibromopropane linker (CN-Pr-ß-CD/Cu(II)). The prepared catalyst was characterized using FT-IR, XRD, FE-SEM, EDS, TGA, ICP-OES, BET, and TEM analyses. CN-Pr-ß-CD/Cu(II) was subsequently applied in a direct oxidative amidation reaction and it was observed that different benzyl alcohols were converted to desire amides with good to excellent efficiency. This reaction was performed in the presence of amine hydrochloride salts, tert-butyl hydroperoxide (TBHP), and Ca2CO3 in acetonitrile (CH3CN) under nitrogen atmosphere. CN-Pr-ß-CD/Cu(II) can be recycled and reused five times without significant reduction in reaction efficiency.

Graphitic Carbon Nitride Nanosheets Covalently Functionalized with Biocompatible Vitamin B1: Synthesis, Characterization, and Its Superior Performance for Synthesis of Quinoxalines.

The physical properties of two-dimensional nanosheet materials make them promising candidates as active materials in the areas of photoelectronics, fuel cells, sensors, water splitting, solar energy conversion, CO2 reduction, and heterogeneous catalysis. Among two-dimensional nanosheet materials, graphitic carbon nitride due to its electronic structure and high chemical and thermal stability possesses unique properties. Covalent functionalization of graphitic carbon nitride could be the key step in modifying its ability and significantly improving its properties. To this purpose, a novel strategy for the covalent functionalization of g-C3N4 nanosheets (CN) with vitamin B1 (VB1) by using 1,3-dibromopropane as a covalent linker for the first time is demonstrated. The obtained CN-Pr-VB1 exhibits increased thermal stability compared to the VB1 which is important in the practice application and can be easily dispersed in common organic solvents. The efficacy of the CN-Pr-VB1 as a heterogeneous organocatalyst was evaluated in the quinoxaline synthesis under solvent-free conditions and afforded good isolated yield with high purity. Moreover, the prepared catalyst could be facilely recycled and reused for seven consecutive cycles without a noticeable decrease in the catalytic activity. Extensive characterization confirmed the stability of morphology and chemical structure after recyclability of the CN-Pr-VB1.