Trans-influences in mononuclear cyclopalladated compounds containing a σ(Pd–Csp2, ferrocene) bond. X-ray crystal structures of [Pd{[(η5-C5H3)–CHN–CH2–C6H5]Fe(η5-C5H5)}(X)(PPh3)] with X−=Br− and I−

The syntheses, characterization and study of the properties of cyclopalladated compounds of general formula: [Pd{[(η5-C5H3)–CHN–CH2–C6H5]Fe(η5-C5H5)}(X)(PPh3)] with X−=Cl−, Br−, I−, CN−, SCN− or AcO− are reported. Compounds with X−=Br− and I− were characterized by X-ray diffraction, and their crystal structures revealed the existence of a weak C–H⋯X interaction involving one of the –CH2– type hydrogen atoms bound to the imine nitrogen. Comparison of the spectroscopic properties of these compounds has allowed us to elucidate the influence of the monoanionic ligand, X−, on a trans-arrangement to the metallated carbon atom upon the environment of the iron(II). Theoretical studies based on the semiempirical PM3(tm) were also been carried out to clarify the effects produced by the X− ligand on the ring current of the metallated C5H3 ring of the ferrocenyl fragment.