MPTMS

MPTMS, or 3-mercaptopropyltrimethoxysilane, is an organosilane reagent used to functionalize oxide surfaces with thiol groups. The molecule features a silicon atom bound to three methoxy groups and to a propyl chain ending in a thiol (−SH) group. This combination enables simultaneous surface silanization and introduction of a reactive thiol terminus for subsequent chemistry.

In the presence of moisture, the methoxy groups hydrolyze to silanols and condense with surface hydroxyls, forming Si–O–Si linkages that anchor the molecule to substrates such as silica, glass, or titania. The exposed thiol group can bind to metals and metal nanoparticles or participate in disulfide formation, enabling immobilization of biomolecules or catalytic ligands and serving as a platform for grafting thiol-containing polymers or ligands.

Applications include self-assembled monolayers on oxide surfaces for biosensing and catalysis, immobilization of metals or nanoparticles, surface-initiated polymerization, and as a crosslinker in sol–gel and hybrid materials. MPTMS can be used to create thiol-functionalized surfaces prior to gold-thiol chemistry or to anchor ligands that require a thiol handle. Its use requires control of hydrolysis and condensation conditions to avoid excessive polymerization and to achieve uniform films.

Handling and safety: MPTMS is moisture-sensitive and should be stored under dry, inert conditions. It can irritate skin, eyes, and the respiratory tract and should be handled in a fume hood with appropriate PPE. It hydrolyzes to release alcohols during storage and use, and films may form siloxane networks if exposed to moisture.