Thiolfunctional

Thiol-functional refers to molecules, polymers, surfaces, or materials that bear one or more thiol (−SH) groups. The thiol group is a sulfur-containing functional group that imparts distinctive reactivity and binding properties, notably toward soft metals and unsaturated carbon frameworks, enabling conjugation, crosslinking, and surface modification.

Chemically, thiols are more acidic than alcohols, with typical pKa values in the approximate range of 8 to 10 for aliphatic thiols in water. The thiolate anion (RS−) is a soft, highly nucleophilic species that readily engages in oxidation to form disulfides (RSSR) and participates in a variety of carbon–sulfur bond-forming reactions. Thiols also undergo thioether formation through alkylation, participate in thiol-ene radical additions, and can be conjugated to maleimides or other electrophiles in bioconjugation schemes. In many contexts, thiols are protected during synthesis (for example, with trityl or Acm groups) and deprotected when needed.

Synthesis and functionalization strategies aim to install or preserve thiol groups on small molecules, polymers, surfaces, and nanoparticles. Common approaches include thiol-activation of halides, displacement of sulfonates, or reduction of disulfides, as well as post-functionalization of pre-formed scaffolds. The robust affinity of thiols for noble metals makes thiol-functional materials especially valuable for surface modification, sensor interfaces, and nanoparticle stabilization. Thiol-ene click chemistry is a widely used method to link thiol groups with alkenes under mild conditions.

Applications span biofunctionalization, catalysis, materials science, and nanotechnology. Safety considerations note that many thiols have strong odours and corrosive or toxic potential, requiring appropriate ventilation and handling.