Synthesis, characterization, and applications in Heck and Suzuki coupling reactions of amphiphilic cyclopalladated ferrocenylimines

A series of novel amphiphilic ferrocenylimines and their cyclopalladated complexes of general formula [Fe(η5-C5H5)(η5-C5H4CR1double bond; length as m-dashNR2)] (R1=H, R2=C12H25-n 4a, R1=H, R2=C16H33-n 4b, R1=CH3, R2=C12H25-n 4c, R1=CH3, R2=C16H33-n 4d), [PdCl{[(η5-C5H5)]Fe[(η5-C5H3)CR1double bond; length as m-dashNR2]}]2 (5a–d), [PdCl{[(η5-C5H5)]Fe[(η5-C5H3)–CR1double bond; length as m-dashNR2]}(PPh3)] (6a–d), were prepared and characterized by 1H NMR, 13C NMR, 31P NMR, IR, HRMS, and elemental analysis. The crystal structures of 5c,d were determined by X-ray crystallography. These amphiphilic cyclopalladated complexes are thermally stable and insensitive to oxygen and moisture. The redox properties of 4a–d, 5a–d, 6a–d were also investigated using cyclic voltammetric technique. Compounds 5a–d, 6a–d displayed good activity in the Heck reaction of a variety of aryl halides with ethyl acrylate or styrene and the Suzuki–Miyaura cross-coupling reaction of aryl bromides with phenylboronic acid in bulk solution. They are also suitable for formation of Langmuir–Blodgett (LB) films.