Bonding studies of transition-metal complexes. Part II. Helium-I photoelectron spectra of homoleptic d0,d1, and d10 tetrakis(dialkylamides) of transition and Group 4B metals and tungsten hexakis(dimethylamide)

Abstract

He(I) Photoelectron (p.e.) spectra of the compounds M(NR₂)₄(M = C, Si, Ge, Sn, Ti, Zr, Hf, or V; R = Me). M′(NR′₂)₄(M′= Ti, Zr, or Hf; R = Et), and W(NMe₂)₆ have been measured. The first band(s) in all spectra [except that of V(NMe₂)₄ which has a lone d electron] have been assigned to ionisation from molecular orbitals (m.o.s) regarded as linear combinations of the nitrogen ‘lone-pair’ atomic orbitals (a.o.s). The next band corresponds to the main σ(M–N) bonding orbital, while there is an unresolved collection of peaks to higher ionisation potential (i.p.) corresponding to ionisation from the –NR₂ bonding m.o.s. From the form of the nitrogen ‘lone-pair’ section of the spectra it is possible to infer structural information about the molecules.