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Thiosulfate (IUPAC-recommended spelling; sometimes thiosulphate in British English) is an oxyanion of sulfur with the chemical formula S 2 O 2− 3. Thiosulfate also refers to the compounds containing this anion, which are the salts of thiosulfuric acid , such as sodium thiosulfate Na 2 S 2 O 3 and ammonium thiosulfate (NH 4 ) 2 S 2 O 3 .
Sodium thiosulfate (sodium thiosulphate) is an inorganic compound with the formula Na 2 S 2 O 3 ·(H 2 O) x. Typically it is available as the white or colorless pentahydrate (x = 5), which is a white solid that dissolves well in water.
Illustrative coordination complexes of thiosulfate. Thiosulfate is a potent ligand for soft metal ions. A typical complex is [Pd(S 2 O 3) 2 (ethylenediamine)] 2−, which features a pair of S-bonded thiosulfate ligands. Simple aquo and ammine complexes are also known. [2]
MTSL is attached to proteins by reaction with thiol groups. The reaction exploits standard reactivity of thiosulfate esters. Methanesulfinate (CH 3 SO 2 −) is the leaving group: RSO 2 S-nitroxide + protein-SH → protein-S-S-nitroxide + RSO 2 H. The heterodisulfide bond to the cysteine residue is robust, enabling site-directed spin labelling.
Conversion of simple disulfides to thiosulfinates results in a considerable weakening of the S–S bond from about 47.8 to 28.0 kcal mol −1 for the S-S bond in PhS(O)SPh and from about 63.2 to 39.3 kcal mol −1 for the S-S bond in MeS(O)SMe, [14] with the consequence that most thiosulfinates are both unstable and quite reactive.
Sodium thiosulfate is used to reduce iodine back to iodide before the iodine can complex with the starch to form the characteristic blue-black color. Iodine is generated: 2 I − + S 2 O 2− 8 → I 2 + 2 SO 2− 4. And is then removed: I 2 + 2 S 2 O 2− 3 → 2 I − + S 4 O 2− 6. Once all the thiosulfate is consumed the iodine may form a ...
12.69 is the conversion factor from mEq sodium thiosulfate to grams of iodine (the molecular weight of iodine is 126.9 g/mol); W is the weight of the sample in grams. The determination of IV according to Wijs is the official method currently accepted by international standards such as DIN 53241-1:1995-05, AOCS Method Cd 1-25, EN 14111 and ISO ...
Tetrathionate has also been found to serve as a terminal electron acceptor for Salmonella enterica serotype Typhimurium, whereas existing thiosulfate in the small intestines of mammals is oxidized by reactive oxygen species released by the immune system (mainly NADPH oxidase produced superoxide) to form tetrathionate. This aids in the growth of ...