Synthesis, characterization and reactions of novel ferrocenylimidazoles as donor ligands

In this project a series of ferrocenylimidazole derivatives were successfully prepared and characterized using an array of analytical techniques. Reactions of ferrocenylcarbinols with N,N′-thiocarbonyldiimidazole under both solvent-free conditions and in dichloromethane are described. The reaction of ferrocenylmethanol afforded S,S-bis(ferrocenylmethyl)dithiocarbonate, the reaction of α-substituted ferrocenylcarbinols provided ferrocenylalkylimidazolides, while ω-ferrocenylcarbinols yielded ferrocenylimidazolecarbothioates. The reactions were carried out under solvent-free conditions, consistent with the principles of Green Chemistry. Ferrocenyl benzyl ethers were successfully prepared by reacting 4-ferrocenylbenzyl-1Hcarboxylate with a series of primary alcohols under catalytic condition and under a catalyst– free environment. Refluxing a mixture of alcohol-water and 4-ferrocenylbenzyl-1Hcarboxylate provided the corresponding ethers in modest yields. The same ethers were obtained at room temperature by employing potassium tetrachloroplatinate or hydrochloric acid as catalyst. Ferrocenyl-1H-imidazole, 4-ferrocenylphenyl-1H-imidazole and their corresponding ferrocenyl-3-subsitituted imidazolium salts have been successfully synthesized. The compounds were characterized and the electrochemical properties of selected imidazolium salts were examined by cyclic voltammetry. Additionally, X-ray structures of two of the imidazolium salts were determined. The imidazolium salts were found to be good catalysts for the Heck and Suzuki cross-coupling reactions