Spontaneous Vesicle Formation of Monododecenyl Phosphonic Acid in Water

Abstract

We report the synthesis of amphiphilic dodecenyl phosphonic acid PC 12 from vinylphosphonic acid, a reactive phosphonic acid intermediate. The trans-P-C=C moiety enabled PC 12 to disperse well in water. Surface tension and dynamic light scattering measurements revealed that PC 12 exhibited high surface activity and reduced the surface tension of water from 72.0 to 23.6 mN/m, thereby resulting in the spontaneous formation of aggregates even in a dilute aqueous solution (critical aggregation concentration (CAC) = 4.8 × 10-4 M). In contrast to modern lipids with double-tailed structures, the PC 12 of simple singletailed structure spontaneously formed bilayered vesicles, without an external energy supply. Compared with the strength of hydrogen bonds formed by the long, saturated alkyl chain of dodecyl phosphonic acid (DPA), the strength of PC 12 intermolecular hydrogen bonds was weaker. The melting point of PC 12 was approximately 20℃ lower than that of DPA. These results indicate that the trans-P-C=C moiety was considerably important for spontaneous vesicle formation in water. Preliminary modeling of the morphological transitions of the closed bilayer structures in the vesicles was then conducted, by varying the pH and adding an α-helical peptide scaffold.

Synthesis of a Bolaamphiphilic Alkenyl Phosphonic Acid by Ru-catalyzed Olefin Cross Metathesis Reaction

“…Based on the signal intensity of dimethyl sulfide as an internal standard, the water solubility of BPC 12 was estimated to be 3.35 g L 1 1.0 10 2 M at 25 . This value is higher than that of a similar bolaamphiphile of tetradecanedioic acid having a saturated It was also confirmed that PC 12 formed a colloidal dispersion in water and did not precipitate at concentrations of up to 40 wt in water 24 . DPA without the trans-P C C moiety was less soluble in D 2 O 2.8 10 4 M .…”