Isomerism of the cyclopalladated ferrocenylketimines

Abstract Five new cyclopalladated ferrocenylketimines with the general formula [PdCl(η 5 -C 5 H 5 )Fe(η 5 -C 5 H 3 CMe=NC 6 H 4 R)(PPh 3 )](R = 2-OMe 3a, 2-OEt 3b, 2-Me 3c, 2-Br 3d, 2,4,6-trimethyl 3e) have been synthesized and characterized to be mixtures of anti and syn isomers in solution except for 3e. It was confirmed that the cause of this isomerism is that the free rotation around the C—N bond is hindered. Attempts to synthesize ferrocenylketimines in which R = 2,6-dichloro, 2,6-dibromo, 2,4,6-tribromo failed to yield new products, but only obtained the condensation product of two molecules of acetylferrocene. Copyright © 1996 Elsevier Science Ltd