Perfluorinated Trialkoxysilanol with Dramatically Increased Brønsted Acidity.

Area of Science:

• Organosilicon Chemistry
• Fluorine Chemistry
• Acid-Base Chemistry

Background:

• Silanols are silicon analogs of alcohols, with varying acidity.
• Orthosilicic acid is a fundamental inorganic silanol.
• Understanding silanol acidity is crucial for catalysis and materials science.

Purpose of the Study:

• To synthesize and characterize a novel perfluorinated trialkoxysilanol.
• To quantify the Brønsted acidity of this new compound.
• To investigate the properties of its conjugate base.

Main Methods:

• Synthesis of {(F3 C)3 CO}3 SiOH.
• Brønsted acidity determination via pKa measurements.
• Spectroscopic analysis (NMR, IR) of the silanol and its silanolate.

Main Results:

• The perfluorinated trialkoxysilanol exhibits Brønsted acidity over 13 orders of magnitude higher than orthosilicic acid.
• Deprotonation by amines and pyridines yields silanolates.
• These silanolates feature remarkably short Si-O bonds, similar to silanones.

Conclusions:

• Perfluorinated substituents dramatically enhance silanol Brønsted acidity.
• The resulting silanolates are highly reactive intermediates with unique structural features.
• This discovery opens new avenues in organosilicon chemistry and catalysis.