Fabrication of DABCO functionalized poly(ionic liquids): Vital role of ferric oxides in the formation of mesoporous structure and used as highly efficient and recyclable catalysts for multi-component reactions

Polymerized and Colloidal Ionic Liquids─Syntheses and Applications

The breadth and importance of polymerized ionic liquids (PILs) are steadily expanding, and this review updates advances and trends in syntheses, properties, and applications over the past five to six years. We begin with an historical overview of the genesis and growth of the PIL field as a subset of materials science. The genesis of ionic liquids (ILs) over nano to meso length-scales exhibiting 0D, 1D, 2D, and 3D topologies defines colloidal ionic liquids, CILs, which compose a subclass of PILs and provide a synthetic bridge between IL monomers (ILMs) and micro to macro-scale PIL materials. The second focus of this review addresses design and syntheses of ILMs and their polymerization reactions to yield PILs and PIL-based materials. A burgeoning diversity of ILMs reflects increasing use of nonimidazolium nuclei and an expanding use of step-growth chemistries in synthesizing PIL materials. Radical chain polymerization remains a primary method of making PILs and reflects an increasing use of controlled polymerization methods. Step-growth chemistries used in creating some CILs utilize extensive cross-linking. This cross-linking is enabled by incorporating reactive functionalities in CILs and PILs, and some of these CILs and PILs may be viewed as exotic cross-linking agents. The third part of this update focuses upon some advances in key properties, including molecular weight, thermal properties, rheology, ion transport, self-healing, and stimuli-responsiveness. Glass transitions, critical solution temperatures, and liquidity are key thermal properties that tie to PIL rheology and viscoelasticity. These properties in turn modulate mechanical properties and ion transport, which are foundational in increasing applications of PILs. Cross-linking in gelation and ionogels and reversible step-growth chemistries are essential for self-healing PILs. Stimuli-responsiveness distinguishes PILs from many other classes of polymers, and it emphasizes the importance of segmentally controlling and tuning solvation in CILs and PILs. The fourth part of this review addresses development of applications, and the diverse scope of such applications supports the increasing importance of PILs in materials science. Adhesion applications are supported by ionogel properties, especially cross-linking and solvation tunable interactions with adjacent phases. Antimicrobial and antifouling applications are consequences of the cationic nature of PILs. Similarly, emulsion and dispersion applications rely on tunable solvation of functional groups and on how such groups interact with continuous phases and substrates. Catalysis is another significant application, and this is an historical tie between ILs and PILs. This component also provides a connection to diverse and porous carbon phases templated by PILs that are catalysts or serve as supports for catalysts. Devices, including sensors and actuators, also rely on solvation tuning and stimuli-responsiveness that include photo and electrochemical stimuli. We conclude our view of applications with 3D printing. The largest components of these applications are energy related and include developments for supercapacitors, batteries, fuel cells, and solar cells. We conclude with our vision of how PIL development will evolve over the next decade.

Copper (II) complex supported on magnetic nanoparticles as a novel nanocatalyst for the synthesis of imidazo[1,2-a]pyridines

Research on the synthesis of imidazo[1,2-a]pyridines has gained great importance among synthetic chemists because there have been numerous reports of their biological and medicinal activities. In this respect, we fabricated CuCl2 immobilized on Fe3O4 nanoparticles modified with 1,10-phenanthroline-5,6-diol [Fe3O4@Diol/Phen-CuCl2] and investigated its catalytic activity for the preparation of imidazo[1,2-a]pyridine derivatives through one-pot three-component reaction of 2-aminopyridines, aldehydes and terminal alkynes under ecofriendly conditions. FT-IR spectroscopy, EDX, SEM, TEM, XRD, TGA, VSM and ICP-OES techniques employed in order to identify the structure of the as-constructed Fe3O4@Diol/Phen-CuCl2 nanocatalyst. This catalytic system has a series of advantages such as the synthesis of imidazo[1,2-a]pyridine products with high yields in suitable time, performing the reactions in an environmentally friendly solvent (PEG), easy preparation of the catalyst with a simple method, and the recyclability of the Fe3O4@Diol/Phen-CuCl2 nanocatalyst.

Magnet-responsive choline carbomer ionogels as a versatile and recyclable catalyst for one-pot synthesis of benzopyran in water

Ionogels are gaining popularity as a potential replacement for volatile organic solvents in various processes, such as catalysts, electrochemistry, spectroscopy, and medicinal chemistry, due to their low toxicity, high thermal stability, and good solubility. Magnet-responsive ion gels with high magnetic susceptibility are promising and can be used as catalysts, sensors, and MRI contrast agents. Herein, we fabricated simple and novel magnet choline carbomer ionogels using a precipitation-deposition method with carbomers and choline hydroxide. The morphology and structure of the resulting ionogels were analyzed using various characterization techniques, including FTIR, EDX, TGA, and SEM spectroscopy. These magnet ionogels were effective catalysts for a one-pot, three-component synthesis of benzopyran derivatives, providing mild reaction conditions, environmental friendliness, and good to excellent (78-96%) yields within a short reaction time (1-2 h). Additionally, the magnet ionogels were easily recyclable, and they could be reused up to five times without catalytic deactivation.

Highly efficient synthesis of C3-heteroaryl 3-fluorooxindoles via a one-pot stepwise Ce(iii)/photoassisted cross-dehydrogenative coupling/fluorooxidation process

A one-pot stepwise strategy has been developed to afford C3-heteroaryl 3-fluorooxindoles via a Ce(iii)/photoassisted cross-dehydrogenative coupling/fluorooxidation process in moderate-to-good yields with excellent functional group compatibility.

Investigation of the mechanism of small size effect in carbon-based supercapacitors

A small size effect could be conducive to enhancing the electrochemical performance, while the mechanism by which they also increase the capacitance for carbon electrode materials has not been established. Here, ultrasmall polyacrylonitrile particles with controllable sizes are supported on poly(ionic liquid)s microspheres (PILMs/PAN) by epitaxial polymerization growth strategy. Unlike traditional subtraction formulas in developing a porous architecture, we report on the synthesis of creating numerous micro/mesopores in carbon materials by addition theorem, and thus making for the perfection of packing density, which has not been reported yet. As an example, PILMC/PAN-L with a well-balanced specific surface area of 875.38 m² g^-1 and packing density of 1.05 g cm^-3 demonstrated gravimetric and volumetric capacitances of 309 F g^-1 and 324.45 F cm^-3 at 0.5 A g^-1, showing good rate performance and stable cyclability. Moreover, the underlying mechanism is thoroughly developed using multiple electrochemical methods. On this basis, this work would afford avenues to further enhancing the electrochemical performance, especially in exploring advanced carbon materials.