title: The effect of the sulfur position on the melting points of lipidic 1-methyl-3-thiaalkylimidazolium ionic liquids.
abstract: A series of novel lipid-inspired ionic liquids have been synthesized employing the thiol-ene "click" reaction in a single-step process. The thermal properties were determined by differential scanning calorimetry (DSC) and showed observable trends between the C16, C18, and C20 analogues. The minimum melting points for each equivalent chain length series occur at sequential odd sulfur positions, 3, 5, and 7 for the C16, C18, and C20 series, respectively. The magnitude of melting point depression relative to the saturated homologue is observed to have a strong dependence on the position of the sulfur in the side chain. Additionally, the sulfur position corresponding to the lowest melting point for a homologous series shifts further down the chain as the chain length is increased, indicating that the maximum effect takes place near the center of the ion and not the center of the thiaalkyl chain. This synthesis provides tunability and improved thermal stability for 1-methyl-3-thiaalkylimidazolium bistriflimides and insight into structure-property relationships of lipidic ionic liquids.
authors.affiliation: Department of Chemistry, ‡Department of Chemical & Biomolecular Engineering, University of South Alabama , Chemistry 223, Mobile, Alabama 36688, United States.
authors.forename: Richard A
authors.initials: RA
authors.lastname: O'Brien
authors.forename: Arsalan
authors.initials: A
authors.lastname: Mirjafari
authors.forename: Kaila M
authors.initials: KM
authors.lastname: Mattson
authors.forename: Samuel M
authors.initials: SM
authors.lastname: Murray
authors.forename: Niloufar
authors.initials: N
authors.lastname: Mobarrez
authors.forename: E Alan
authors.initials: EA
authors.lastname: Salter
authors.forename: Andrzej
authors.initials: A
authors.lastname: Wierzbicki
authors.forename: James H
authors.initials: JH
authors.lastname: Davis
authors.forename: Kevin N
authors.initials: KN
authors.lastname: West
mesh_terms: D002152:Calorimetry, Differential Scanning; D007093:Imidazoles / Q000737:chemistry*; D052578:Ionic Liquids / Q000737:chemistry*; D008055:Lipids / Q000737:chemistry*; D008956:Models, Chemical; D015394:Molecular Structure; D011789:Quantum Theory; D013455:Sulfur / Q000737:chemistry*; D013816:Thermodynamics
chemical_list: D007093:Imidazoles; D052578:Ionic Liquids; D008055:Lipids; D013455:Sulfur