Electronic spectra and electronic structures of ketenimines and carbodiimides
Abstract
U.v. absorption spectra of ketenimines (C
N
N–) and carbodi-imides (–N
C
N–) with phenyl and alkyl groups as substituents are reported. Band assignments are achieved by relying primarily on comparisons with structurally related molecules, in particular allenes (
C
C
C
), isocyanates (–N
C
O), and imines (
C
N–). More detailed information about the excited singlet states of the molecules is deduced from semiempirical CNDO/S–Cl calculations. These calculations are also used for a description of the electronic structures of ketenimines and carbodi-imides in terms of molecular orbitals and electron density distributions.