Thiocyanate#Test for iron.28III.29

Thiocyanate occurs widely in nature, albeit often in low concentrations. It is a component of some sulfur cycles.

Thiocyanate hydrolases catalyze the conversion of thiocyanate to carbonyl sulfide{{cite journal |doi=10.1021/ja057010q |title=Thiocyanate Hydrolase is a Cobalt-Containing Metalloenzyme with a Cysteine-Sulfinic Acid Ligand |date=2006 |last1=Katayama |first1=Yoko |last2=Hashimoto |first2=Kanako |last3=Nakayama |first3=Hiroshi |last4=Mino |first4=Hiroyuki |last5=Nojiri |first5=Masaki |last6=Ono |first6=Taka-aki |last7=Nyunoya |first7=Hiroshi |last8=Yohda |first8=Masafumi |last9=Takio |first9=Koji |last10=Odaka |first10=Masafumi |journal=Journal of the American Chemical Society |volume=128 |issue=3 |pages=728–729 |pmid=16417356 }} and to cyanate:{{cite journal|doi=10.1073/pnas.1922133117 |title=Trinuclear Copper Biocatalytic Center Forms an Active Site of Thiocyanate Dehydrogenase |date=2020 |last1=Tikhonova |first1=Tamara V. |last2=Sorokin |first2=Dimitry Y. |last3=Hagen |first3=Wilfred R. |last4=Khrenova |first4=Maria G. |last5=Muyzer |first5=Gerard |last6=Rakitina |first6=Tatiana V. |last7=Shabalin |first7=Ivan G. |last8=Trofimov |first8=Anton A. |last9=Tsallagov |first9=Stanislav I. |last10=Popov |first10=Vladimir O. |journal=Proceedings of the National Academy of Sciences |volume=117 |issue=10 |pages=5280–5290 |doi-access=free |pmid=32094184 |bibcode=2020PNAS..117.5280T |pmc=7071890 }}

:{{chem2|SCN- + H2O + H+ -> SCO + NH3}}

:{{chem2|SCN- + H2O -> OCN- + H2S}}

Thiocyanate{{ cite journal |author1=Pedemonte, N. |author2=Caci, E. |author3=Sondo, E. |author4=Caputo, A. |author5=Rhoden, K. |author6=Pfeffer, U. |author7=di Candia, M. |author8=Bandettini, R. |author9=Ravazzolo, R. |author10=Zegarra-Moran, O. |author11=Galietta, L. J. | title = Thiocyanate Transport in Resting and IL-4-Stimulated Human Bronchial Epithelial Cells: Role of Pendrin and Anion Channels | journal = Journal of Immunology | year = 2007 | volume = 178 | issue = 8 | pages = 5144–5153 | pmid = 17404297 | doi=10.4049/jimmunol.178.8.5144|doi-access=free }} is known to be an important part in the biosynthesis of hypothiocyanite by a lactoperoxidase.{{ cite journal |author1=Conner, G. E. |author2=Wijkstrom-Frei, C. |author3=Randell, S. H. |author4=Fernandez, V. E. |author5=Salathe, M. | title = The Lactoperoxidase System Links Anion Transport to Host Defense in Cystic Fibrosis | journal = FEBS Letters | year = 2007 | volume = 581 | issue = 2 | pages = 271–278 | pmid = 17204267 | pmc = 1851694 | doi = 10.1016/j.febslet.2006.12.025 }}{{ cite journal |author1=White, W. E. |author2=Pruitt, K. M. |author3=Mansson-Rahemtulla, B. | title = Peroxidase-Thiocyanate-Peroxide Antibacterial System Does not Damage DNA | journal = Antimicrobial Agents and Chemotherapy | year = 1983 | volume = 23 | issue = 2 | pages = 267–272 | pmid = 6340603 | pmc = 186035 | doi=10.1128/aac.23.2.267}}{{ cite journal |author1=Thomas, E. L. |author2=Aune, T. M. | title = Lactoperoxidase, Peroxide, Thiocyanate Antimicrobial System: Correlation of Sulfhydryl Oxidation with Antimicrobial Action | journal = Infection and Immunity | year = 1978 | volume = 20 | issue = 2 | pages = 456–463 | pmid = 352945 | pmc = 421877 | doi = 10.1128/IAI.20.2.456-463.1978 }} Thus the complete absence of thiocyanate or reduced thiocyanate{{ cite journal | author1 = Minarowski, Ł. | author2 = Sands, D. | author3 = Minarowska, A. | author4 = Karwowska, A. | author5 = Sulewska, A. | author6 = Gacko, M. | author7 = Chyczewska, E. | title = Thiocyanate concentration in saliva of cystic fibrosis patients | journal = Folia Histochemica et Cytobiologica | year = 2008 | volume = 46 | issue = 2 | pages = 245–246 | pmid = 18519245 | doi = 10.2478/v10042-008-0037-0 | url = http://versita.metapress.com/content/12805r021413m867/fulltext.pdf | doi-access = free }}{{Dead link|date=June 2018 |bot=InternetArchiveBot |fix-attempted=no }} in the human body, (e.g., cystic fibrosis) is damaging to the human host defense system.{{ cite journal |author1=Moskwa, P. |author2=Lorentzen, D. |author3=Excoffon, K. J. |author4=Zabner, J. |author5=McCray, P. B. Jr. |author6=Nauseef, W. M. |author7=Dupuy, C. |author8=Bánfi, B. | title = A Novel Host Defense System of Airways is Defective in Cystic Fibrosis | journal = American Journal of Respiratory and Critical Care Medicine | year = 2007 | volume = 175 | issue = 2 | pages = 174–183 | pmid = 17082494 | pmc = 2720149 | doi = 10.1164/rccm.200607-1029OC }}{{ cite journal | author = Xu, Y.; Szép, S.; Lu, Z. | title = The antioxidant role of thiocyanate in the pathogenesis of cystic fibrosis and other inflammation-related diseases | journal = Proceedings of the National Academy of Sciences of the United States of America | year = 2009 | volume = 106 | issue = 48 | pages = 20515–20519 | pmid = 19918082 | pmc = 2777967 | doi = 10.1073/pnas.0911412106 |bibcode = 2009PNAS..10620515X | last2 = Szep | last3 = Lu | doi-access = free }}

Thiocyanate is a potent competitive inhibitor of the thyroid sodium-iodide symporter.{{ cite journal |author1=Braverman L. E. |author2=He X. |author3=Pino S. | title = The effect of perchlorate, thiocyanate, and nitrate on thyroid function in workers exposed to perchlorate long-term | journal = J Clin Endocrinol Metab | year = 2005 | volume = 90 | issue = 2 | pages = 700–706 | pmid = 15572417 | doi = 10.1210/jc.2004-1821| url = http://jcem.endojournals.org/content/90/2/700.long |display-authors=etal| doi-access = free }} Iodine is an essential component of thyroxine. Since thiocyanates will decrease iodide transport into the thyroid follicular cell, they will decrease the amount of thyroxine produced by the thyroid gland. As such, foodstuffs containing thiocyanate are best avoided by iodide deficient hypothyroid patients.{{cite web|title=Hypothyroidism|url=http://umm.edu/health/medical/altmed/condition/hypothyroidism|website=umm.edu|publisher=University of Maryland Medical Center|access-date=3 December 2014}}

In the early 20th century, thiocyanate was used in the treatment of hypertension, but it is no longer used because of associated toxicity.{{cite journal | title =Toxicity of Thiocyanates Used in Treatment of Hypertension |author1=Warren F. Gorman |author2=Emanuel Messinger |author3=And Morris Herman | journal = Ann Intern Med | year =1949 | volume = 30 | issue = 5 | pages = 1054–1059 | doi = 10.7326/0003-4819-30-5-1054|pmid=18126744 }} Sodium nitroprusside, a metabolite of which is thiocyanate, is however still used for the treatment of a hypertensive emergency. Rhodanese catalyzes the reaction of sodium nitroprusside (like other cyanides) with thiosulfate to form the metabolite thiocyanate.

{{main|Transition metal complexes of thiocyanate}}

File:PalenikPdPN SCN NCSic1970.svg

{{image frame|content=|align=right|width=250|caption=Resonance structures of the thiocyanate ion}}

Thiocyanate shares its negative charge approximately equally between sulfur and nitrogen. As a consequence, thiocyanate can act as a nucleophile at either sulfur or nitrogen—it is an ambidentate ligand. [SCN]⁻ can also bridge two (M−SCN−M) or even three metals (>SCN− or −SCN<). Experimental evidence leads to the general conclusion that class A metals (hard acids) tend to form N-bonded thiocyanate complexes, whereas class B metals (soft acids) tend to form S-bonded thiocyanate complexes. Other factors, e.g. kinetics and solubility, are sometimes involved, and linkage isomerism can occur, for example [Co(NH₃)₅(NCS)]Cl₂ and [Co(NH₃)₅(SCN)]Cl₂.Greenwood, p. 326 It [SCN] is considered as a weak ligand. ([NCS] is a strong ligand){{Cite web|title=coordination compounds|url=https://ncert.nic.in/ncerts/l/lech109.pdf}}

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| image1 = Pentaaquathiocyanatoiron(II)-3D-balls.png

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| image2 = Aqueous_ferric_thiocyanate_(Fe(SCN)n)_hydrate_mix.jpg

| caption2 = The blood-red colored (up) complex [Fe(NCS)(H₂O)₅]²⁺ (left), indicates the presence of Fe³⁺ in solution.

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If [SCN]⁻ is added to a solution with iron(III) ions, a blood-red solution forms mainly due to the formation of [Fe(NCS)(H₂O)₅]²⁺, i.e. pentaaqua(thiocyanato-N)iron(III). Lesser amounts of other hydrated compounds also form: e.g. Fe(SCN)₃ and [Fe(SCN)₄]⁻.Greenwood, p. 1090

Similarly, Co²⁺ gives a blue complex with thiocyanate.{{Cite journal|last=Uri|first=N|date=1947-01-01|title=The stability of the cobaltous thiocyanate complex in ethyl alcohol-water mixtures and the photometric determination of cobalt|journal=Analyst|volume=72|issue=860|pages=478–481|doi=10.1039/AN9477200478|pmid=18917685|bibcode=1947Ana....72..478U}} Both the iron and cobalt complexes can be extracted into organic solvents like diethyl ether or amyl alcohol. This allows the determination of these ions even in strongly coloured solutions. The determination of Co(II) in the presence of Fe(III) is possible by adding KF to the solution, which forms uncoloured, very stable complexes with Fe(III), which no longer react with SCN⁻.{{Cite journal |last=Kolthoff |first=I. M. |date=1930 |title=The Cobalt-Thiocyanate Reaction for the Detection of Cobalt and Thiocyanate |url=http://link.springer.com/10.1007/BF02759120 |journal=Mikrochemie |language=en |volume=8 |issue=S1 |pages=176–181 |doi=10.1007/BF02759120 |issn=0369-0261}}

Phospholipids or some detergents aid the transfer of thiocyanatoiron into chlorinated solvents like chloroform and can be determined in this fashion.{{cite journal|last1=Stewart|first1=J.C.|title=Colorimetric determination of phospholipids with ammonium ferrothiocyanate|journal=Anal. Biochem.|date=1980|volume=104|issue=1|pages=10–14|doi=10.1016/0003-2697(80)90269-9|pmid=6892980}}

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• Sulphobes

• {{Greenwood&Earnshaw}}

{{Reflist}}

{{Cyanides}}

{{Thiocyanates}}

{{Inorganic compounds of carbon}}

{{Thyroid hormone receptor modulators}}

Category:Anions

Category:Sulfur ions

Category:Concrete admixtures