thiole

Thiole is a term sometimes used to refer to thiols, a class of organosulfur compounds that contain a sulfhydryl group (-SH). In contemporary English, the standard term is thiol, but thiole can appear in translations or older literature.

Chemically, a thiole has the general structure R-SH, where R is an alkyl or aryl group. Common examples include methanethiol (CH3SH), ethanethiol (C2H5SH), and benzenethiol (C6H5SH, also called thiophenol). The suffix -thiol is used in IUPAC naming to indicate the presence of the sulfhydryl group.

Physical properties and acidity: Thiols are polar and often exhibit characteristic, strong odors. They are weak acids, with pKa values around 10, meaning they can form thiolate anions under basic conditions. The -SH group can participate in hydrogen bonding and redox chemistry, affecting reactivity and boiling points.

Reactivity and applications: The sulfur atom in thiols is nucleophilic, enabling alkylation to form thioethers (R-S-R'). Thiols readily oxidize to disulfides (R-S-S-R), a process important in protein folding and stability. They also serve as ligands in coordination chemistry and as nucleophiles in various organic syntheses. In biology, thiol groups occur in cysteine residues and in molecules like glutathione, playing central roles in redox biology and metabolism.

Occurrence and safety: Thiols occur in many natural products and flavors; methanethiol is a metabolic byproduct and a common odorant in emissions from decay and some foods. Due to strong odors and potential toxicity, thiols are handled with appropriate ventilation and protective equipment.

In summary, thiole is an alternate term for thiol; modern usage typically adheres to the term thiol.