Vesicular Membrane with Structured Interstitial Water.

Self-assembled vesicles with structured (tetrahedral order with strong hydrogen bonds) interstitial water are reported. The vesicles, known as MCsome, are assembled from metal carbonyl compounds, FpR (Fp = (Cp)Fe(PPh3)(CO)(CO-), Cp = cyclopentadiene, R = C3Bithiophene, C6Pyrene or C6) with the Fp heads exposed to water. The R groups are surrounded by the interstitial water with the hydrogen bonding strength variable depending on the hydrophobicity of R groups. The structure of the interstitial water is responsible for the integrity of the membrane and swelling behaviour of the vesicles. This constructional role of water opens new concepts for the creation of aqueous assemblies with water-mediated functions.