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oai:recercat.cat:10256/113332024-06-18T13:49:17Zcom_2072_452955com_2072_2054col_2072_453073

00925njm 22002777a 4500 dc Fernández Wang, Martí author Ferré Romeu, Meritxell author Pla i Quintana, Anna author Parella Coll, Teodor author Pleixats, Roser author Roglans i Ribas, Anna author 2014 Bis-silylated dihydroimidazolium salt 1 and monosilylated imidazolium salt 2 are transformed to (NHC)RhCl(COD) complexes 3 and 4, allowing the preparation of hybrid silica materials either by sol-gel or grafting processes. Full characterization of the materials by means of solid state NMR, N-2-sorption measurements, thermogravimetric analysis (TGA) and elemental analysis was followed by evaluation of catalytic activity in the [2+2+2] cycloaddition of alkynes. Excellent yields of the cycloadducts are obtained for up to six consecutive cycles with the grafted material, using simple filtration to recover the catalyst. Both conventional and microwave heating prove effective for the process described Financial support from the Spanish Ministerio de Ciencia e Innovacion (MICINN) (grant numbers CTQ2011-23121, CTQ2009-07881, CTQ2012-32436, CTQ2011-22649, CSD2007-00006) and by the Generalitat de Catalunya (grant numbers 2009SGR637, 2009SGR1441, and predoctoral grant to M. Fernandez) is acknowledged. M. Ferre thanks the Universitat Autonoma de Barcelona for a predoctoral scholarship http://hdl.handle.net/10256/11333 Catàlisi heterogènia Heterogeneous catalysis Catalitzadors de rodi Rhodium catalyst Reaccions d'addició Addition reactions Rodi Rhodium Ciclització (Química) Ring formation (Chemistry) Rhodium-NHC Hybrid Silica Materials as Recyclable Catalysts for [2+2+2] Cycloaddition Reactions of Alkynes