Synthesis of new adamantyl-imine palladium(II) complexes and their application in Mizoroki-Heck and Suzuki-Miyaura C C cross-coupling reactions
| Autor: | Asanda C. Matsheku, Munaka C. Maumela, Banothile C. E. Makhubela |
|---|---|
| Rok vydání: | 2021 |
| Předmět: |
Steric effects
chemistry.chemical_classification 010405 organic chemistry Aryl Aryl halide Imine chemistry.chemical_element 010402 general chemistry 01 natural sciences Combinatorial chemistry Coupling reaction 0104 chemical sciences Catalysis Inorganic Chemistry chemistry.chemical_compound chemistry Materials Chemistry Moiety Physical and Theoretical Chemistry Palladium |
| Zdroj: | Polyhedron. 205:115280 |
| ISSN: | 0277-5387 |
| DOI: | 10.1016/j.poly.2021.115280 |
| Popis: | Improving carbon–carbon cross-coupling reactions is an ongoing process and finding the most versatile and stable catalyst precursors has been of great interest. Ligand design has been proven to be important since it is responsible for providing electron density and steric saturation around the metal centre, thus contributing towards the stereo-electronic properties. The adamantyl moiety has been used to generate highly bulky and electron-rich ligands for application in palladium-catalysed cross-coupling reactions. Accordingly, we have prepared some Schiff-base adamantyl ligands (L1-L3) and complexed them with [PdCl2(MeCN)2] to afford the (pre)catalysts C1-C3, which were successfully applied in Mizoroki-Heck and Suzuki-Miyaura carbon–carbon cross-coupling reactions. The cross-coupling reaction products were obtained in good yields using 0.5 mol % Pd catalyst loading. C2 and C3 showed remarkable activity in the Mizoroki-Heck coupling reactions involving substrates with substituents on the olefin and aryl halide (including 4-Cl, 4-CH3, -CO2Me and -CO2Et). We also, observed that the Suzuki-Miyaura cross-coupling system was active towards challenging activated and deactivated aryl chlorides, with to up 70% conversions recorded. The mercury poisoning tests conducted revealed that the catalysts act as homogenous molecular active species in the Mizoroki-Heck reactions and act as both homogenous and heterogeneous catalysts in the Suzuki-Miyaura cross-coupling reactions. |
| Databáze: | OpenAIRE |
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