title: 1H NMR studies of aerosol-OT reverse micelles with alkali and magnesium counterions: preparation and analysis of MAOTs.
abstract: Simple procedures and characterization of a series of well-defined precursors are described for preparation of a unique microenvironment in nanoreactors, reverse micelles. The Na(+), K(+), Rb(+), Cs(+), and Mg(2+) surfactants were prepared using liquid-liquid ion exchange using chloride and nitrate salts. The surfactants were characterized using (1)H NMR spectroscopy and a variety of other techniques. (1)H NMR spectroscopy was found to be a sensitive probe for characterization of the size of the nanoreactor as well as its water content. (1)H NMR spectra can be used for detailed characterization of reactions in confined environments when counterion effects are likely to be important. (1)H NMR spectroscopy revealed two separate peaks corresponding to water in Mg(AOT)2 samples; one peak arises from water coordinated to the Mg(2+) ion while the other peak arises from bulk water. The two water signals arise directly from the slow exchange of the water coordinated to Mg(2+) in these microemulsions with water in the water pool, and provide an opportunity to study hydration of Mg(2+). This work thus extends the potential use of MAOT microemulsions for applications such as in green chemistry.
authors.affiliation: Department of Chemistry, Colorado State University, Fort Collins, Colorado 80523-1872, USA.
authors.forename: Michelle L
authors.initials: ML
authors.lastname: Stahla
authors.forename: Bharat
authors.initials: B
authors.lastname: Baruah
authors.forename: Dustin M
authors.initials: DM
authors.lastname: James
authors.forename: Michael D
authors.initials: MD
authors.lastname: Johnson
authors.forename: Nancy E
authors.initials: NE
authors.lastname: Levinger
authors.forename: Debbie C
authors.initials: DC
authors.lastname: Crans
mesh_terms: D002712:Chlorides / Q000737:chemistry; D003510:Cyclohexanes / Q000737:chemistry; D004143:Dioctyl Sulfosuccinic Acid / Q000737:chemistry*; D004563:Electrochemistry / Q000379:methods; D006863:Hydrogen-Ion Concentration; D007477:Ions; D008274:Magnesium / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D008823:Micelles; D008968:Molecular Conformation; D053758:Nanoparticles / Q000737:chemistry; D036103:Nanotechnology / Q000379:methods; D009566:Nitrates / Q000737:chemistry; D013386:Succinates / Q000737:chemistry*; D013501:Surface-Active Agents / Q000737:chemistry
chemical_list: C512554:1,4-bis(2-ethylhexyl) sodium sulfosuccinate; D002712:Chlorides; D003510:Cyclohexanes; D007477:Ions; D008823:Micelles; D009566:Nitrates; D013386:Succinates; D013501:Surface-Active Agents; D004143:Dioctyl Sulfosuccinic Acid; C506365:Cyclohexane; D008274:Magnesium