Carbanion mechanisms XX. Is there charge delocalization in phenyl-substituted Group 4 anions? Evidence from electronic absorption spectroscopy

Article abstract of DOI:10.1016/0022-328X(95)05770-P

From the electronic absorption spectra of the triphenyl silyl, germyl, stannyl and plumbyl anions Ph₃E^- (E = Si, Ge, Sn or Pb), it is concluded that there exists in these species almost no conjugation between the Group 4 element and the phenyl group substituents, contrasting with the Ph₃C^- carbanion. A similar conclusion can be drawn from the near constancy of λ_max values in the series Ph₃Si^-, Ph₂SiH^- and PhSiH^-₂.