Shamrock surfactants

Surfactants 6 (2,2,17,17,32,32-hexamethyl-2,17,32-triazoniatritriacontane triiodide/trichloride), 7 (2,2,19,19,36,36-hexamethyl-2,19,36-triazoniaheptatriacontane triiodide/trichloride), 8 (sodium [12-[[11-[(carboxylatomethyl)carbamoyl]undecyl]dimethylammonio]dodecanoylamino]ethanoate), 9 (disodium 12-[dimethyl-[12-(hydrogenphosphato)dodecyl]ammonio]dodecyl phosphate), and 10 (O,O′-bis[(12-trimethylammonio)dodecyl]phosphate bromide), which are new shamrock surfactants, were synthesized and characterized. Shamrocks represent a novel class of surfactants that contain a central head group connected to two flanking head groups by hydrocarbon chains; they do not contain long-chain alkyl groups. Surfactants 6–10 were characterized in water by measurement of their Krafft temperatures and critical aggregation concentrations, and their aggregates were studied by 1H and 31P NMR spectroscopy, dynamic laser light scattering, and phase-contrast optical microscopy. Aqueous 6b and 7b were also studied by cryo-etch high resolution scanning electron microscopy. The NMR results are consistent with small aggregates such as micelles or small vesicles, although the light scattering results suggest that the aggregates are larger. Phase-contrast optical microscopy indicated that coacervates are formed upon the undisturbed hydration of 6–10. The structural character of shamrock surfactants may be favorable for coacervate formation.