Poly(pyrazol-1-ylmethyl)benzene Palladium Complexes: Synthesis, Characterisation and Evaluation as Heck Coupling Catalysts

Abstract

The poly(pyrazol-1-ylmethyl)benzenes L1 - L5 react with [PdCl2(NCMe)2] or [PdClMe(COD)] to form dinuclear palladium complexes [{PdClX(3,5-Me2pzCH2)2-1,2-C6H4}2] (X = Cl (1), Me (2)), [{PdCl2(3,5-Me2pzCH2)2-1,3-C6H4}2] (3), palladium complexes [{Pd2(μ-Cl)2Me2(3,5- Me2pzCH2)2-1,3-C6H4}] (4), [{Pd2(μ-Cl)2X2(3,5-Me2pzCH2)2-1,4-C6H4}] (X = Cl (5), Me (6)), [{Pd2(μ-Cl)2Cl2(3,5-tBu2pzCH2)2-1,4-C6H4}] (7), and tetranuclear [{Pd2(μ-Cl)2Cl2(3,5- Me2pzCH2)2}2-1,4-C6H4] (8). The structures of 1, 2 and 8 were confirmed by X-ray structure analysis. The complexes efficiently catalyse the coupling reaction of iodobenzene and butylacrylate at 80 °C.