Polyhedral Oligomeric Silsesquioxane D_3h-(RSiO_1.5)₁₄.

Area of Science:

• Materials Science
• Organic Chemistry
• Nanotechnology

Background:

• Larger polyhedral oligomeric silsesquioxanes (POSS) with n>12 are challenging to synthesize and authenticate.
• Existing methods for larger POSS systems are lengthy and yield low quantities.

Purpose of the Study:

• To present a facile and high-yielding synthesis of a specific larger POSS cage.
• To characterize the largest crystallographically authenticated POSS cage with organic substituents.

Main Methods:

• Treatment of T7Ph7(OH)3 silsesquioxane with catalytic trifluoromethanesulfonic acid.
• Isolation of the T14Ph14 framework in crystalline form.
• Analysis using single crystal X-ray diffraction, multinuclear NMR, and thermal analysis.
• Density Functional Theory (DFT) methods for isomer energy determination.

Main Results:

• Achieved surprisingly straightforward and high-yielding access to the phenyl-substituted D3h-symmetric T14 isomer (T14Ph14).
• Successfully isolated and characterized the largest POSS cage (T14Ph14) with organic substituents.
• Determined relative energies of all four possible T14Ph14 isomers using DFT.

Conclusions:

• The developed method offers an efficient route to larger POSS structures.
• This work expands the scope of accessible POSS cages for advanced applications.
• The findings facilitate further research into the properties and applications of large POSS systems.