Silica-Supported Dendrimer-Palladium Complex-Catalyzed Selective Hydrogenation of Dienes to Monoolefins

Abstract

The selective hydrogenation of cyclic and acyclic dienes to monoolefins occurs under very mild conditions, in the presence of silica-supported PAMAM-Pd complexes. The activity and selectivity of this reaction is sensitive to the dendrimer structure.These dendritic complexes display excellent recycle properties, retaining activity for up to eight recycles.

PAMAM Dendrimer Templated Nanoparticle Catalysts

“…These can subsequently be used to bind Pd( II ) and catalyze intramolecular carbonylations en route to the preparation of fused heterocycles containing O, N, and S heteroatoms [65] as well as the selective hydrogenation of dienes to monoolefi ns [66] . Additionally, dendrimers constructed on mesoporous SBA silicas have been used to template Pd nanoparticles and catalyze allyl alcohol hydrogenation (see Fig.…”

Dendrimer-Stabilized Ru Nanoparticles Immobilized in Organo-Silica Materials for Hydrogenation of Phenols

“…Therefore they were not removed from the carrier structure, which is typical in a number of works, using dendrimers only as templates for regular pore formation and uniform particle size distribution [41,[71][72][73]. Herein the sol-gel method allows diffusion limitations to be avoided, inevitable, when bulky dendrimer or dendron is anchored to the surface of ready carrier [64][65][66][67][68][69]. The materials obtained were characterized by infrared spectroscopy (IR), X-ray photoelectron spectroscopy (XPS) and solid-state nuclear magnetic resonance (NMR) spectroscopy, that confirmed the presence in their structures of fragments, inherent in the SiO 2 bulk support [74,75] [76][77][78][79][80].…”

“…Traditional hybrid catalysts, based on amorphous or mesoporous silica and PPI or PAMAM dendrimers, are synthesized via dendron immobilization onto the surface of ready carrier [41,[63][64][65][66][67][68][69][70]. These materials are characterized by low dendrimer content and irregular dendrimer coating of the surface: anchoring of subsequent bulky dendrons is hindered due to diffusion limitations (bulky dendrons interfere with each other).…”

Chemo‐selective reduction of nitro and nitrile compounds using Ni nanoparticles immobilized on hyperbranched polymer‐functionalized magnetic nanoparticles

“…[5,6] Three structures for a catalyst delivery system have been investigated, namely the core of the dendrimer as the single catalytic unit, [7] the dendritic box (intermediate positions within a dendrimer) [8] and the terminal ends of the dendrimer that covalently bind to catalytic units. [9][10][11][12][13] There are many examples of the use of functionalized dendrimers in catalysis of reactions including Heck couplings, [14][15][16] decarboxylation, [17] oxidation, [18] reduction, [19] Michael addition [20] and so on.…”