Cucurbit[6]uril-Supported Fe3O4 Magnetic Nanoparticles Catalyzed Green and Sustainable Synthesis of 2-Substituted Benzimidazoles via Acceptorless Dehydrogenative Coupling

Synthesis of new hybrid pyridines catalyzed by Fe3O4@SiO2@urea-riched ligand/Ch-Cl

Herein, a new heterogeneous catalytic system through modification of urea functionalized magnetic nanoparticles with choline chloride [Fe₃O₄@SiO₂@urea-riched ligand/Ch-Cl] was designed and synthesized. Then, the synthesized Fe₃O₄@SiO₂@urea-riched ligand/Ch-Cl was characterized by using FT-IR spectroscopy, FESEM, TEM, EDS-Mapping, TGA/DTG and VSM techniques. After that, the catalytic usage of Fe₃O₄@SiO₂@urea-riched ligand/Ch-Cl was investigated for the synthesis of hybrid pyridines with sulfonate and/or indole moieties. Delightfully, the outcome was satisfactory and the applied strategy represents several advantages such as short reaction times, convenience of operation and relatively good yields of obtained products. Moreover, the catalytic behavior of several formal homogeneous DESs was investigated for the synthesis of target product. In addition, a cooperative vinylogous anomeric-based oxidation pathway was suggested as rational mechanism for the synthesis of new hybrid pyridines.

Thermodynamically-Consistent Modeling of Ferromagnetic Hysteresis

Models of ferromagnetic hysteresis are established by following a thermodynamic approach. The class of constitutive properties is required to obey the second law, expressed by the Clausius-Duhem inequality, and the Euclidean invariance. While the second law states that the entropy production is non-negative for every admissible thermodynamic process, here the entropy production is viewed as a non-negative constitutive function. In a three-dimensional setting, the magnetic field and the magnetization are represented by invariant vectors. Next, hysteretic properties are shown to require that the entropy production is needed in an appropriate form merely to account for different behavior in the loading and the unloading portions of the loops. In the special case of a one-dimensional setting, a detailed model is determined for the magnetization function, in terms of a given susceptibility function. Starting from different initial magnetized states, hysteresis cycles are obtained by solving a nonlinear ordinary differential system. Cyclic processes with large and small amplitudes are established for materials such as soft iron.

Efficient preparation of graphene oxide-immobilized copper complex and its catalytic performance in the synthesis of imidazoles

This paper focused on the synthesis of phenylthiocarbamide-grafted graphene oxide (GO)-supported Cu complex (Cu-PTC@GO) as a highly efficient and recyclable catalyst synthesis by various analytical techniques such as TG, FT-IR, XRD, BET, N₂ adsorption-desorption isotherms, SEM, EDX, and elemental mapping analysis. Cu-PTC@GO showed outstanding results in preparing various imidazoles with higher yields, reduced reaction time, ease of product separation, and a simple procedure. In addition, the catalyst demonstrated appreciable recyclability up to five successive runs, and there was no substantial loss in catalytic performance. The result indicated that the heterogeneous base GO catalyst performed high activity and excellent recyclability in synthesizing various imidazoles and their derivatives, owing to the unique state of the GO-supported copper complex.

Cucurbit[6]uril supported β-Ni(OH)2 nanoparticles as a heterogeneous catalyst for the synthesis of quinazolines via acceptorless dehydrogenative coupling of alcohols with nitriles

Synthesis of a series of quinazolines using β-Ni(OH)2-CB[6] as a heterogeneous nanocatalyst.