Overview

3-Glycidoxypropyltrimethoxysilane (GPTMS) is a versatile functionalizing agent of silicas, metal hydroxide surfaces, and polymer crosslinker.

Reactions

The silicon-stable octet configuration and low polarity of Sisingle bondC and Sisingle bondO bonds control its inorganic reactions in water. Its hydrolysis and condensation involve hypervalent silicon centers, explained by the negative hyperconjugation of the anomeric Si and the partial π character of the Sisingle bondO bond.

The high reactivity of 3-Glycidoxypropyltrimethoxysilane's epoxy ring has been shown towards nucleophiles such as azide anions, primary and secondary amines but not for thiols and alcohols in organic solvents. The formation of ester bonds in water at pH 6.0–7.5, especially with organic acid moieties, has been also demonstrated with propanoic acid at 40°C. The nucleophilic addition does not occur with propylamine, propanol, and propanthiol in water, but these nucleophiles can catalyze the inorganic condensation. The control of the reaction conditions, especially the pH and aging time, tuning the inorganic-organic reactivity.

Applications in Hydrogen Peroxide Sensing

3-Glycidoxypropyltrimethoxysilane plays a critical role in the in situ synthesis of noble metal nanoparticles, particularly enhancing applications in hydrogen peroxide sensing. This silane compound functions primarily as a mediator in the reduction of metal salts treated with 3-aminopropyltrimethoxysilane during sol-gel processes. The synthesized nanoparticles, including those of gold, silver, and palladium, are notable for their uniform spherical shapes and controlled sizes, which are directly applicable in creating thin films for sensors.¹

Reference

1. Pandey PC, Chauhan DS. 3-Glycidoxypropyltrimethoxysilane mediated in situ synthesis of noble metal nanoparticles: application to hydrogen peroxide sensing. Analyst. 2012; 137(2): 376-385.