Ionic conduction, microwave-assisted

The structures of trisubstituted imidazoles are prevalent in natural products and pharmacologically active compounds, like the known P38 map kinase inhibitor and losartan. Besides, triarylimidazoles display various bioaclive effects such as herbi-cidal, fungicidal, analgesic, anti-inflammatory, and antithrombotic activities as well. The three-component synthesis of 2,4,5-trisubstituted imidazoles, a typical acid-catalyzed reaction, could be conducted successfully with good to excellent yields in a neutral ionic liquid, l-methyl-3-heptyl-imidazolium tetrafluoroborate ([Hemim] [BF ]), under solvent-free and microwave-assisted conditions (Fig. 12.46) [31],... 

In most of the synthesized materials of different compounds in ionic liquids, we obtained one-dimensional structures. The ionic-conductive nature and polarizability of the ionic liquids helps in the movement and polarization of ions under the rapidly changing electric field of the microwaves. This results in high heating and in the transient, anisotropic microdomains for the reaction system, which assists the anisotropic growth of the nanostructures. 

William et al. (2005) reviewed various techniques for characterization and trends in the field of nanocomposites. These are new materials made with fillers, which have nanosize and have a big potential for applications in the automotive and aerospace industiy as well as in construction, electrical applications and food packing. There is a tremendous interest for using bio-nanoparticles in the new era of biocomposites by using synthetic and natural fillers in polymer nanocomposites. Aranda et al. (1998) studied the microwave-assisted blending-intercalation of ion-conductor polymers into layered silicates. They prepared organo-inorganic hybrid nanocomposites derived from poly(ethylene oxide) and montmorillonite silicate. They observed that ionic conductivity was enhanced as compared to samples prepared by intercalation from solution. 

The assistance of microwave heating has been also proposed to accelerate RCM reactions using classic ruthenium-based catalysts. The reaction can be rapidly conducted in either ionic liquids, such as [bmim][BF4], or in a micro-wave transparent solvent such as dichloromethane. 

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