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

Abstract

A series of novel amphiphilic ferrocenylimines and their cyclopalladated complexes of general formula [Fe(η 5-C 5H 5)(η 5-C 5H 4CR 1 NR 2)] (R 1=H, R 2=C 12H 25- n 4a, R 1=H, R 2=C 16H 33- n 4b, R 1=CH 3, R 2=C 12H 25- n 4c, R 1=CH 3, R 2=C 16H 33- n 4d), [PdCl{[(η 5-C 5H 5)]Fe[(η 5-C 5H 3)CR 1 NR 2]}] 2 ( 5a– d), [PdCl{[(η 5-C 5H 5)]Fe[(η 5-C 5H 3)–CR 1 NR 2]}(PPh 3)] ( 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.