New palladium catalyst immobilized on epoxy resin: synthesis, characterization and catalytic activity

• Published in: Applied organometallic chemistry 2016-01, Vol.30 (1), p.4-11
• Main Authors: Sienkiewicz, Natalia, Strzelec, Krzysztof, Pospiech, Piotr, Cypryk, Marek, Szmechtyk, Tomasz
• Format: Article
• Language: English
• Subjects: epoxy resins; heterogeneous catalysts; hydrogenation reaction; Mizoroki-Heck reaction; polythiourethanes; properties and characterization; structure-property relations
• ISSN: 0268-2605; 1099-0739
• DOI: 10.1002/aoc.3389

A new thiol‐functionalized epoxy resin as a support for palladium(II) complexes has been synthesized in good yields. A palladium catalyst was ‘heterogenized’ by anchoring [PdCl2(PhCN)2] complexes to these thiol‐functionalized polymers via ligand exchange reaction. These new palladium catalysts were tested in Mizoroki–Heck coupling and hydrogenation reactions. The activity of the complexes in terms of yield is comparable to that of homogeneous PdCl2(PhCN)2. The stability and a good recycling efficiency of these catalysts make them useful for prolonged use. The constant and good selectivity of the supported catalysts during recycling experiments indicate that they could be useful for practical application in many organic reactions. To characterize the heterogeneous complexes before and after use, X‐ray photoelectron spectroscopy, infrared spectroscopy, scanning electron microscopy, energy dispersive X‐ray microscopy, atomic absorption spectroscopy and time‐of‐flight secondary ion mass spectrometry were applied. Density functional theory calculations were also used to better understand the structures of the obtained palladium complexes. Polythiourethanes contain three atoms, oxygen, nitrogen and sulfur, capable of coordinating to transition metals. We examined the possibility of intra‐ and intermolecular binding for both cis and trans palladium complexes. Copyright © 2015 John Wiley & Sons, Ltd. A new thiol‐functionalized epoxy resin was used as support for palladium(II) complexes. Functionalized epoxy resins are being explored for many applications, especially in catalysis, where palladium can effectively catalyse various reactions. Epoxy resin cured with polythiourethanes contains oxygen, nitrogen and sulfur atoms which can bind transition metals.