Gd. Smith et al., QUANTUM-CHEMISTRY STUDY OF LI-1,2-DIMETHOXYPROPANE COMPLEXES(), The journal of physical chemistry. A, Molecules, spectroscopy, kinetics, environment, & general theory, 101(17), 1997, pp. 3152-3157
Quantum chemistry studies of the lowest energy conformers of 1,2-dimet
hoxypropane (DMP) complexes with Li+ ions have been carried out. Resul
ts of these calculations are compared with those of our recent study o
f Li+-1,2-dimethoxyethane (DME) complexes. Because of a chiral center,
conformation space is more complex for DMP than for the structurally
similar but achiral DME. Qualitatively similar behavior to that seen p
reviously in studies of DME is found, however, including the presence
of low-energy conformers containing consecutive gauche dihedrals of op
posite sense and stronger interactions of the Li+ ion with conformers
containing O-C-C-O gauche conformations, The former is a result of sta
bilization of conformers by attractive 1,5 CH3-O electrostatic interac
tions, while the latter reflects the ability of the ion to interact wi
th both ether oxygen atoms. The calculated Li+-DMP complex energies an
d geometries reveal that favorable interactions of the or methyl group
with the ion result in a Li+-t (g) over bar t complex energy comparab
le that of the Li+-tgt complex. Comparison of calculated Raman spectra
with experimental measurements on DMP/LiClOs4 solutions indicates an
increasingly high population of the t (g) over bar t conformer with in
creasing salt content.