Structure of a super base in tetrahydrofuran solution studied by 6Li,1H HOESY, 133Cs,1H HOESY, and MNDO. Evidence for discrete species rather than a mixed aggregate

Abstract

Lithium trityl (Ph 3 CLi) and cesium 3-ethyl-3-heptoxide were studied as model components of a «super base» by using 6 Li, 1 H HOESY and 133 Cs, 1 H HOESY (HOESY=heteronuclear Overhauser effect spectroscopy), as well as by 1 H, 1 H ROESY (ROESY=rotating frame nuclear Overhauser effect spectroscopy). At 25 o C in THF-d 8 solution, the individual species are present partly (Ph 3 CLi) or quantitatively (cesium alkoxide) as contact ion pairs