Photoelectron spectra and bonding of (N–B)-2,8,9-trioxa-5-aza-1-borabicyclo[3.3.3]undecane (boratran) and some 2,8,9-trioxa-5-aza-1-silabicyclo[3.3.3]undecanes (silatrans)

Abstract

The He(I) photoelectron spectra of silatrans [N(CH₂CH₂O)₃]SiR, (I: R = H, Me, or OEt), and boratran [N-(CH₂CH₂O)₃]B, (II), are compared with those of the non-cage triethoxy-compounds and with that of the parent tris(2-hydroxyethyl)amine. The shifts observed in the N 2p lone-pair band are discussed in relation to internal σ-donation to the empty p orbital of boron or d orbitals of silicon and to interaction with oxygen lone-pair levels.