Li+ and Li+I-Li+ ions Solvated by 1,4-dioxane: An ion Mobility Spectrometry-Mass Spectrometry Study

Electrospray ionization (ESI) and ion mobility spectrometry-mass spectrometry (EMS-MS) were employed to investigate the solvated structures of ionic species in the lithium iodide electrolyte solution in the gas phase. The Li+I-Li+ triple ion and single standalone Li+ ions solvated by 1,4-dioxane were successfully generated and observed by ESI-MS under the influence of dioxane vapor at the inlet region. Under the present experimental condition, (1,4-dioxane)(m)center dot Li(+)complex ions (m = 1, 2, and 3) and a (1,4-dioxane)center dot Li+I-Li+ complex ion were observed, which were further examined by EMS to investigate their structures. The presence of multiple structural isomers was confirmed, which accounts for the endothermic conformational transition of 1,4-dioxane from a chair to a boat to achieve bidentate O-donor binding to Li+ and Li+I-Li+. Further structural details critical for the ion-solvent interactions were also examined and discussed with the help of density functional theory calculations.