Effects of the nature of the nitrogen donor atom (sp2versus sp3) upon the properties and chemistry of palladated complexes with σ(Pd–Csp2, ferrocene) bonds
Abstract
The NMR and Mössbauer spectra and electrochemistry of the N-donor ferrocenyl ligands [Fe(η5-C5H5){(η5-C5H4CHNCH2Ph)}] and [Fe(η5-C5H5)(η5-C5H4CH2NMe2)] as well as their mononuclear derivatives with σ(Pd–Csp2, ferrocene) bonds [[graphic omitted]CH2Ph)}Cl(L)], [[graphic omitted]Me2)}Cl(L)][L = 1 -methylimidazole (mim) or PPh3], and [Pd{(η5-C5H5)Fe(η5-C5H3CH2NMe2)}Cl(PPh3)2] have been studied. Comparison of the data allows an understanding of the influence of the nature of the N-donor atom of the ferrocenyl moiety (sp2versus sp3) upon the properties of these compounds. In particular, the differences observed in the quadrupole splitting parameters obtained from Mössbauer spectroscopy reveal not only that the palladium(II) acts as an electron-withdrawing group in all these cyclometallated derivatives, but also that most of the electron density is withdrawn from the imine CH
N moiety in the derivatives containing ferrocenyl Schiff bases as ligands. The crystal structures of [[graphic omitted]CH2Ph)}Cl(PPh3)] and [[graphic omitted]Me2)}Cl(mim)] have been determined.