Bonding studies of transition–metal complexes. Part III. He(I) photoelectron spectra of three-co-ordinate homoleptic bis(trimethylsilyl)amides of scandium, titanium, chromium, iron, gallium, and indium

Abstract

The He(I) photoelectron (p.e.) spectra of a number of three-co-ordinate metal amides M[N(SiMe₃)₂]₃(M = Sc, Ti, Cr, Fe, Ga, or In) are presented. The spectrum of the d⁰ scandium compound shows two bands at ionisation potential (i.p.) <9 eV, which are assigned to lone-pair orbitals. The spectra of the open-shell compounds are very similar, and it is concluded that bands corresponding to ionisation from the metal 3d orbitals lie at i.p. >9 eV, or are masked by bands due to ionisation from nitrogen lone-pair orbitals (>8.1 eV). This is attributed to a strong –I effect of the ligand which, in contrast to the situation in corresponding dialkylamides such as V(NMe₂)₄, is not counterbalanced by a [graphic omitted] πinteraction because of strong competing [graphic omitted](p→d)π bonding.