Question

The phosphazene compound that acts as a superbase is

• A.
• B.
• C.
• D.

Hint:

Phosphazene superbases are characterized by strong electron-donating substituents and resonance-stabilized structures. Recognize them by the P=N motif and bulky alkyl or cyclic amine groups.

Answer 1

The Correct Option is C

Phosphazene bases are a class of organophosphorus compounds known for their strong basicity. The key features contributing to superbase behavior are:

• Presence of electron-donating groups such as tert-butyl (tBu) or alkyl chains.
• Delocalization of the lone pair on nitrogen over the phosphazene backbone.
• Resonance stabilization of the conjugate acid.

In option (C), the compound has the general structure of a phosphazene base with:

• A P=N bond, which helps stabilize the negative charge via resonance.
• Electron-donating tert-butyl groups and piperidine rings that enhance basicity.

This structure corresponds to the family of phosphazene superbases, such as Schwesinger bases, known for their extremely high Brønsted basicity.

Thus, option (C) is the correct answer.

\[ \boxed{\text{Correct phosphazene superbase: (C)}} \]