Spectroscopic study of the complex formation of organolithium compounds with electron donors. 2. Complexes of butyllithium with methyl ethyl and diethyl ethers

Abstract

1. Methyl ethyl ether forms complexes with butyllithium with 1∶4, 2∶4, and 4∶4 compositions, and negligible amounts of 3∶4. Diethyl ether forms complexes with 1∶4 and 2∶4 composition, and in the temperature region from −50 to −100°, small quantities of a 4∶4 complex. 2. The enthalpy of the addition of at least two molecules of methyl ethyl ether to the butyllithium tetramer was found. 3. In the formation of the complex, the methyl ethyl and diethyl ether molecules under-go a transition from flat T- and TT-conformations to nonplanar G- and TG-conformations. 4. The strength of the interaction of ethers with butyllithium depends both on the ionization potential and on steric factors.