title: Cyclohexane as a Li+ selective ionophore.
abstract: The M+[cyclohexane][Ar] (M = Li, Na, and K) cluster ions were investigated using infrared photodissociation spectroscopy in the C-H stretching region. The alkali metal cation binds to the cyclohexane ring above the ring on the S6 axis via eta3 coordination. The C-H stretching modes are perturbed due to binding of the metal cation and display a significant spread in frequency. The shifts are greatest for the Li+ and decrease for Na+ and K+ with increasing ionic radius. It has been observed that cyclohexane displays greater selectivity for Li+ over Na+ than the cyclic ether, 12-crown-4. The charge transfer interaction between Li+ and cyclohexane is believed to be responsible for the selectivity of Li+ over other alkali metal ions.
authors.affiliation: Department of Chemistry, University of Illinois at Urbana Champaign, Urbana, Illinois 61801, USA. naresh@chem.iitb.ac.in
authors.forename: G Naresh
authors.initials: GN
authors.lastname: Patwari
authors.forename: James M
authors.initials: JM
authors.lastname: Lisy