New imidazolyl‐functionalized ordered mesoporous cross‐linked polymers were prepared by the copolymerization of the ionic liquid 3‐benzyl‐1‐vinyl‐1H‐imidazolium bromide with divinylbenzene as the cross‐linker and azobisisobutyronitrile as the radical initiator in the presence of O‐silylated SBA‐15 as the hard template. The materials were characterized by N2 adsorption–desorption analysis, TEM, thermogravimetric analysis, elemental analysis, and FTIR spectroscopy. The material, which benefits from the use of entrapped ionic liquid in the prepared polymer matrix in combination with its ordered mesoporous structure, is an excellent environment for the stabilization of highly dispersed Pd nanoparticles to result in a recyclable catalyst system with a significant activity in the Heck coupling reaction of aryl halides. The presence of well‐distributed imidazolium functionalities in the polymeric framework might be responsible for the relatively uniform and nearly atomic scale distribution of Pd nanoparticles throughout the mesoporous structure and the prevention of Pd agglomeration during the reaction, which results in high durability, high stability, and good recycling characteristics of the catalyst. Although our catalyst system operates in a homogeneous pathway, it is also very stable and recyclable.
An imidazolium based ionic liquid bearing triethylene glycol (TEG) tag was employed as a functional monomer together with divinylbenzene to prepare a novel hydrophilic mesoporous polymer containing ionic liquid functionalities via nanocasting method using SBA‐15 as a hard template. The material was characterized using transmission electron microscopy (TEM), N2 sorption analysis, thermo‐gravimetric analysis (TGA), Fourier‐transform infrared spectroscopy (FT‐IR), elemental analysis (CHN), solid‐state NMR spectroscopy and contact angle measurement. It was found that the hydrophobic/hydrophilic properties of initial template, stepwise addition of monomers and initiator as well as amount of carrier solvent are of the important parameters in preparation of the polymer with uniform pore structure. Benefited from the combined properties such as incorporation of ionic liquid within the pore system of a flexible organic matrix together with its hydrophilic character, the material was found as an appropriate support to generate highly dispersed and very small size of Pd nanoparticles inside the pores. The prepared catalyst in this way, demonstrated outstanding activity, recyclability and high durability in the Suzuki cross‐coupling reaction of varied aryl halides with boronic acids in water as a green reaction medium. The beneficial role of imidazolium ionic liquid in the formation of small and highly active Pd nanoparticles was confirmed with comparative experiments.
A regio- and the diastereoselective ring-expansion reaction of N-acyl aziridine has been described for the synthesis of 4-carboxamide oxazolines using InCl3. A domino Ugi-Joullié/ring expansion reaction of arylphenylazirines, isocyanides, and carboxylic acids led to the target product through N-acylaziridine intermediate in the presence of indium catalyst. The oxazolines were synthesized in moderate to excellent yields with high atom-economy and high bond-forming efficiency under mild reaction conditions.
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