Palladium(II) complexes of (pyridyl)imine ligands as catalysts for the methoxycarbonylation of olefins

摘要

Reactions of 2-methoxy-N-((pyridin-2-yl)methylene)ethanamine (L1), 2-((pyridin-2-yl)methyleneamino)ethanol (L2) and 3-methoxy-N-((pyridin-2-yl)methylene)propan-1-amine (L3) ligands with either [PdCl2(COD)] or [PdCl(Me)(COD)] produced the corresponding monometallic complexes [PdCl2(L1)] (1), [PdClMe(L1)] (2), [PdCl2(L2)] (3) and [PdCl2(L3)] (4). The solid state structure of complex 1 confirmed the bidentate coordination mode of L1, giving a distorted square planar geometry. All the complexes (1-4) formed active catalysts for the methoxycarbonylation of higher olefins to give linear and branched esters. The catalytic behavior of complexes 1-4 were influenced by both the complex structure and olefin chain length.