A Reusable Polymer-anchored Palladium Catalyst for Reduction of Nitroorganics, Alkenes, Alkynes and Schiff Bases†

Abstract

The preparation and utility of a new polymer-anchored Pd II catalyst for the hydrogenation of a wide range of organic substrates is described.

Recoverable Catalysts and Reagents Using Recyclable Polystyrene-Based Supports

“…Table summarizes some of the results obtained. The same catalyst could be used repeatedly and reactions were later extended to include alkenes and alkynes (Table ), , while the catalyst could be stored for more than a year and showed consistent activity even after the tenth recycle.

60 PS-Supported Pd Complex 4.2

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Polymer-supported palladium-imidazole complex catalyst for hydrogenation of substituted benzylideneanilines

“…inert and thermally stable materials like silica, alumina, carbon or polymers are used as supports [4][5][6][7][8][9][10][11][12][13][14][15][16]. Polymer supports have several advantages as they can be functionalised with different types of ligands and the functionalised polymer supports can form stable complexes with different metals suitable for various organic transformations.…”

Homogeneous Hydrogenation of Alkynes and Dienes

“…An important advantage of a heterogeneous catalyst over a homogeneous one concerns the ease of catalyst separation from the products. Therefore, much research effort in this field has been directed towards immobilized palladium complexes, where the palladium is coordinated to a ligand attached to a polymer, a clay, or another inorganic support [37][38][39][40][41][42][43]. Assuming that a single type of palladium species is formed, these heterogenized palladium catalysts are potentially very important and might compete with the Lindlar catalysts in certain applications.…”

“…Formation of complex 40 is proposed to explain the effective protection of the remaining C=C double bond in the catalytic cycle. This species then reacts with molecular hydrogen in an oxidative addition manner to form the dinuclear Zr(IV)-Zr(IV) dihydride complex (41), having one bridging and one terminal hydride. Reductive elimination of the alkenyl and one of the hydrides yields the dinuclear-monohydride bridged complex (42) which then loses the cyclooctene.…”