Cooperative Self-Assembly Process Involving Giant Toroidal Polyoxometalate as a Membrane Building Block in Nanoscale...

Area of Science:

• Supramolecular chemistry
• Materials science
• Nanotechnology

Background:

• Organic amphiphiles self-assemble via hydrophobic effects, forming structures like micelles and liquid crystals.
• The aggregation behavior of inorganic polynuclear entities with organic components remains an area of interest.

Purpose of the Study:

• To investigate the supramolecular behavior of giant toroidal molybdenum blue {Mo154} in the presence of the surfactant n-octyl-β-glucoside (C8G1).
• To elucidate the complex aggregation pathway and resulting nanoscopic hybrid structures.

Main Methods:

• Single-crystal X-ray diffraction and molecular modeling
• Small-angle X-ray scattering and cryo-transmission electron microscopy (cryo-TEM)
• Liquid nuclear magnetic resonance (NMR), viscosimetry, surface tension measurement, and isothermal titration calorimetry

Main Results:

• The {Mo154} anion disrupts the typical micelle formation of C8G1.
• Successive phase transitions from fluid-to-gel and gel-to-fluid were observed.
• Versatile nanoscopic hybrid C8G1-{Mo154} aggregates formed, including crystalline assemblies, smectic lamellar liquid crystals, and vesicles.

Conclusions:

• The superchaotropic nature of {Mo154} drives intimate organic-inorganic interactions.
• {Mo154} acts as a trans-membrane component in large vesicles.
• This study reveals a rich self-assembly scenario driven by inorganic-organic hybrid interactions.