Ionic‐Liquid‐Grafted Rigid Poly(p‐Phenylene) Microspheres: Efficient Heterogeneous Media for Metal Scavenging and Catalysis

Abstract

Novel guanidinium ionic liquid-grafted rigid poly(p-phenylene) (PPPIL) microspheres have been developed for metal scavenging and catalysis. The noble-metal nanoparticles supported on the microspheres surface can be used as efficient heterogeneous catalysts. The combination of nanoparticles and ionic liquid fragments on the microsphere surfaces enhance the activity and durability of the catalyst. The PPPILPd(0) catalyst has been tested in the Suzuki cross-coupling reaction, and exhibits much higher catalytic activity than Pd catalysts supported on porous polymer matrices. The PPPILPd(0) catalyst can be recycled at least for nine runs without any significant loss of activity. The present approach may, therefore, have potential applications in transition-metal-nanocatalyzed reactions.

Cross‐Linked Imidazolium Salts as Scavengers for Palladium

“…Guanidinium ionicliquid-grafted rigid poly(p-phenylene) microspheres efficiently removed [PdCl 4 ] 2À (530 ppm of Pd) and Pd(OAc) 2 (911 ppm of Pd). [10,11] In our case, we reached almost complete removal of the above species upon starting from a much higher amount of palladium (see Table 5). Our materials also show good performances compared with commercially available palladium scavengers.…”

“…[9] However, even if ionic-liquid-based materials are widely used to stabilise palladium species, to give a highly active catalyst for CÀC coupling reactions, less attention has been devoted to the use of covalently supported, ionic-liquid-phase palladium scavengers. Recent examples include guanidinium ionic-liquid-grafted rigid poly(p-phenylene) microspheres, which have been developed for [PdCl 4 ] 2À scavenging, [10] and supported task-specific ionic liquids, which have been developed through the ionic pair coupling of the imidazolium cation of the modified polystyrene support with l-proline. The latter materials have shown an efficient metal-scavenging ability towards Pd(OAc) 2 .…”

Novel Functionalized Microporous Organic Networks Based on Triphenylphosphine

“…In general, catalytic C À C cross-coupling reactions of fluoro-derivatives are rare because of the strong C À F bond. [38] For the practical application of a heterogeneous catalytic system, its stability and reusability are important factors. The reagents can be adsorbed into the porous channels by capillary condensation of the micropores where the catalyst particles are located.…”

“…[37] It is well-known that triphenylphosphine-palladium complexes are widely used for coupling reactions due to their excellent catalytic activity. [38] For the practical application of a heterogeneous catalytic system, its stability and reusability are important factors. For metal-catalyzed reactions, including those involving palladium, leaching of the noble metal is a major cause of catalyst deterioration.…”

Highly facile and efficient assembly of palladium nanoparticles on polystyrene microspheres and their application in catalysis

“…The aggregation of PdNPs will lead to the deterioration of their activity and selectivity in catalytic applications. [2][3][4][5][6][7][8][9][10][11][18][19][20][21][22][23][24][25][26][27] Among known 35 works, the preparation method of polymer-supported PdNPs is mainly so-called in situ method, which was to reduce the different palladium precursors in the presence of solid supports. 30 A number of methods have been developed so far to afford the synthesis of PdNPs on various supports, and during the course of research and development, the supports of interest have shifted from inorganics to polymers because of their merits of simplified synthesis and good dispersibility in water.…”