Concerning the Si—Li bonding in phenylsilyllithiums as studied by variable temperature Li nuclear magnetic resonance

Abstract

A variable temperature 7Li nmr study of equimolar mixtures of two structurally related phenylsilyllithiums supports a bimolecular exchange mechanism between monomeric structures as being responsible for the collapse of the 7Li signals of the two species. The different exchange rates indicated in MTHF and THF parallel the observations from a Si—Li coupling study. The experimental data provide support for a mainly ionic Si—Li bond, although some orbital interaction is indicated.