Detection of Pre-Sol Aggregation and Carbon Dioxide Scrambling in Alkylammonium Alkylcarbamate Gelators by Nuclear Magnetic Resonance

The initial stages of aggregation of a series of organogelator salts, prepared from n -alkylamines by the rapid in situ and isothermal (at room temperature) uptake of the neutral triatomic molecule, CO 2, have been probed by NMR spectroscopy in the nongelled liquid, chloroform- d . Evidence for specific interactions of the ionic headgroups in the aggregates is presented. The influences of concentration and temperature on the processes leading to pre-sol aggregates of decylammonium decylcarbamate ( 2b ) have been investigated in detail. NMR spectra of selectively deuterated (at the α-methylene group) and selectively 13 C-enriched (at the carbonyl carbon) 2b demonstrate that CO 2 is scrambled rapidly between the ammonium and carbamate parts of the molecule in chloroform solution. No scrambling of CS 2 was detected in alkylammonium alkyldithiocarbamates under the same experimental conditions.