Solution structure of the sodium salt of ethyl acetoacetate in the presence of crown ethers: a sodium-23 nuclear magnetic resonance study

Abstract

Anal. of 23Na NMR linewidths in THF solns. of the title salt, in the presence and absence of 15-crown-5 or 18-crown-6, shows conclusively the coexistence of monomeric and dimeric ion pairs, both of which interact with the crown ethers. The kinetically active species in the nucleophilic anion-activated reactions is the 'crowned' ion pair, in which Na+ is linked coordinatively to both the crown ether and its counterion. [on SciFinder (R)]