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Thiocyanate

November 30, 2023

For organic derivatives, see Organic thiocyanates. For the binary compound, ScN, see Scandium nitride.

Thiocyanates are salts containing the thiocyanate anion [SCN]− (also known as rhodanide or rhodanate). [SCN]− is the conjugate base of thiocyanic acid. Common salts include the colourless salts potassium thiocyanate and sodium thiocyanate. Mercury(II) thiocyanate was formerly used in pyrotechnics.

Thiocyanate
Names
Preferred IUPAC name
Thiocyanate[1]
Other names
  • Rhodanide
  • Sulfocyanate
  • Sulphocyanate
  • Thiocyanide
  • Cyanosulfanide
Identifiers
  • 302-04-5 Y
3D model (JSmol)
  • Interactive image
ChEBI
  • CHEBI:18022 Y
ChEMBL
  • ChEMBL84336 N
ChemSpider
  • 8961 Y
  • 4529
  • 9322
UNII
  • O748SU14OM Y
  • InChI=1S/CHNS/c2-1-3/h3H/p-1 Y
    Key: ZMZDMBWJUHKJPS-UHFFFAOYSA-M Y
  • InChI=1/CHNS/c2-1-3/h3H/p-1
    Key: ZMZDMBWJUHKJPS-REWHXWOFAX
  • [S-]C#N
Properties
SCN−
Molar mass 58.08 g·mol−1
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
N verify (what is YN ?)

Thiocyanate is analogous to the cyanate ion, [OCN]−, wherein oxygen is replaced by sulfur. [SCN]− is one of the pseudohalides, due to the similarity of its reactions to that of halide ions. Thiocyanate used to be known as rhodanide (from a Greek word for rose) because of the red colour of its complexes with iron.

Thiocyanate is produced by the reaction of elemental sulfur or thiosulfate with cyanide:

The second reaction is catalyzed by thiosulfate sulfurtransferase, a hepatic mitochondrial enzyme, and by other sulfur transferases, which together are responsible for around 80% of cyanide metabolism in the body.[2]

Biological chemistry of thiocyanate in medicine edit

Thiocyanate[3] is known to be an important part in the biosynthesis of hypothiocyanite by a lactoperoxidase.[4][5][6] Thus the complete absence of thiocyanate or reduced thiocyanate[7] in the human body, (e.g., cystic fibrosis) is damaging to the human host defense system.[8][9]

Thiocyanate is a potent competitive inhibitor of the thyroid sodium-iodide symporter.[10] 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.[11]

In the early 20th century, thiocyanate was used in the treatment of hypertension, but it is no longer used because of associated toxicity.[12] 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 with thiosulfate to form the metabolite thiocyanate. Thiocyanate is also a metabolite of the detoxification of cyanides by Rhodanese.

Coordination chemistry edit

 
Structure of Pd(Me2N(CH2)3PPh2)(SCN)(NCS).[13]
 
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.[14] It [SCN] is considered as a weak ligand. ([NCS] is a strong ligand)[15]

Test for iron(III) and cobalt(II) edit

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

If [SCN]− is added to a solution with iron(III) ions, a blood-red solution forms mainly due to the formation of [Fe(SCN)(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]−.[16]

Similarly, Co2+ gives a blue complex with thiocyanate.[17] 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−.[18]

Phospholipids or some detergents aid the transfer of thiocyanatoiron into chlorinated solvents like chloroform and can be determined in this fashion.[19]

See also edit

References edit

  • Greenwood, Norman N.; Earnshaw, Alan (1997). Chemistry of the Elements (2nd ed.). Butterworth-Heinemann. ISBN 978-0-08-037941-8.

Citations edit

  1. ^ International Union of Pure and Applied Chemistry (2014). Nomenclature of Organic Chemistry: IUPAC Recommendations and Preferred Names 2013. The Royal Society of Chemistry. pp. 784, 1069. doi:10.1039/9781849733069. ISBN 978-0-85404-182-4.
  2. ^ Abraham, Klaus; Buhrke, Thorsten; Lampen, Alfonso (24 February 2015). "Bioavailability of cyanide after consumption of a single meal of foods containing high levels of cyanogenic glycosides: a crossover study in humans". Archives of Toxicology. 90 (3): 559–574. doi:10.1007/s00204-015-1479-8. PMC 4754328. PMID 25708890.
  3. ^ Pedemonte, N.; Caci, E.; Sondo, E.; Caputo, A.; Rhoden, K.; Pfeffer, U.; di Candia, M.; Bandettini, R.; Ravazzolo, R.; Zegarra-Moran, O.; Galietta, L. J. (2007). "Thiocyanate Transport in Resting and IL-4-Stimulated Human Bronchial Epithelial Cells: Role of Pendrin and Anion Channels". Journal of Immunology. 178 (8): 5144–5153. doi:10.4049/jimmunol.178.8.5144. PMID 17404297.
  4. ^ Conner, G. E.; Wijkstrom-Frei, C.; Randell, S. H.; Fernandez, V. E.; Salathe, M. (2007). "The Lactoperoxidase System Links Anion Transport to Host Defense in Cystic Fibrosis". FEBS Letters. 581 (2): 271–278. doi:10.1016/j.febslet.2006.12.025. PMC 1851694. PMID 17204267.
  5. ^ White, W. E.; Pruitt, K. M.; Mansson-Rahemtulla, B. (1983). "Peroxidase-Thiocyanate-Peroxide Antibacterial System Does not Damage DNA". Antimicrobial Agents and Chemotherapy. 23 (2): 267–272. doi:10.1128/aac.23.2.267. PMC 186035. PMID 6340603.
  6. ^ Thomas, E. L.; Aune, T. M. (1978). "Lactoperoxidase, Peroxide, Thiocyanate Antimicrobial System: Correlation of Sulfhydryl Oxidation with Antimicrobial Action". Infection and Immunity. 20 (2): 456–463. doi:10.1128/IAI.20.2.456-463.1978. PMC 421877. PMID 352945.
  7. ^ Minarowski, Ł.; Sands, D.; Minarowska, A.; Karwowska, A.; Sulewska, A.; Gacko, M.; Chyczewska, E. (2008). "Thiocyanate concentration in saliva of cystic fibrosis patients" (PDF). Folia Histochemica et Cytobiologica. 46 (2): 245–246. doi:10.2478/v10042-008-0037-0. PMID 18519245.[permanent dead link]
  8. ^ Moskwa, P.; Lorentzen, D.; Excoffon, K. J.; Zabner, J.; McCray, P. B. Jr.; Nauseef, W. M.; Dupuy, C.; Bánfi, B. (2007). "A Novel Host Defense System of Airways is Defective in Cystic Fibrosis". American Journal of Respiratory and Critical Care Medicine. 175 (2): 174–183. doi:10.1164/rccm.200607-1029OC. PMC 2720149. PMID 17082494.
  9. ^ Xu, Y.; Szép, S.; Lu, Z.; Szep; Lu (2009). "The antioxidant role of thiocyanate in the pathogenesis of cystic fibrosis and other inflammation-related diseases". Proceedings of the National Academy of Sciences of the United States of America. 106 (48): 20515–20519. Bibcode:2009PNAS..10620515X. doi:10.1073/pnas.0911412106. PMC 2777967. PMID 19918082.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  10. ^ Braverman L. E.; He X.; Pino S.; et al. (2005). "The effect of perchlorate, thiocyanate, and nitrate on thyroid function in workers exposed to perchlorate long-term". J Clin Endocrinol Metab. 90 (2): 700–706. doi:10.1210/jc.2004-1821. PMID 15572417.
  11. ^ "Hypothyroidism". umm.edu. University of Maryland Medical Center. Retrieved 3 December 2014.
  12. ^ Warren F. Gorman; Emanuel Messinger; And Morris Herman (1949). "Toxicity of Thiocyanates Used in Treatment of Hypertension". Ann Intern Med. 30 (5): 1054–1059. doi:10.7326/0003-4819-30-5-1054. PMID 18126744.
  13. ^ Palenik, Gus J.; Clark, George Raymond (1970). "Crystal and molecular structure of isothiocyanatothiocyanato-(1-diphenylphosphino-3-dimethylaminopropane)palladium(II)". Inorganic Chemistry. 9 (12): 2754–2760. doi:10.1021/ic50094a028. ISSN 0020-1669.
  14. ^ Greenwood, p. 326
  15. ^ "coordination compounds" (PDF).
  16. ^ Greenwood, p. 1090
  17. ^ Uri, N (1947-01-01). "The stability of the cobaltous thiocyanate complex in ethyl alcohol-water mixtures and the photometric determination of cobalt". Analyst. 72 (860): 478–481. Bibcode:1947Ana....72..478U. doi:10.1039/AN9477200478. PMID 18917685.
  18. ^ Kolthoff, I. M. (1930). "The Cobalt-Thiocyanate Reaction for the Detection of Cobalt and Thiocyanate". Mikrochemie. 8 (S1): 176–181. doi:10.1007/BF02759120. ISSN 0369-0261.
  19. ^ Stewart, J.C. (1980). "Colorimetric determination of phospholipids with ammonium ferrothiocyanate". Anal. Biochem. 104 (1): 10–14. doi:10.1016/0003-2697(80)90269-9. PMID 6892980.

November 30, 2023
thiocyanate, organic, derivatives, organic, thiocyanates, binary, compound, scandium, nitride, salts, containing, thiocyanate, anion, also, known, rhodanide, rhodanate, conjugate, base, thiocyanic, acid, common, salts, include, colourless, salts, potassium, th. For organic derivatives see Organic thiocyanates For the binary compound ScN see Scandium nitride Thiocyanates are salts containing the thiocyanate anion SCN also known as rhodanide or rhodanate SCN is the conjugate base of thiocyanic acid Common salts include the colourless salts potassium thiocyanate and sodium thiocyanate Mercury II thiocyanate was formerly used in pyrotechnics Thiocyanate NamesPreferred IUPAC name Thiocyanate 1 Other names RhodanideSulfocyanateSulphocyanateThiocyanideCyanosulfanideIdentifiersCAS Number 302 04 5 Y3D model JSmol Interactive imageChEBI CHEBI 18022 YChEMBL ChEMBL84336 NChemSpider 8961 YIUPHAR BPS 4529PubChem CID 9322UNII O748SU14OM YInChI InChI 1S CHNS c2 1 3 h3H p 1 YKey ZMZDMBWJUHKJPS UHFFFAOYSA M YInChI 1 CHNS c2 1 3 h3H p 1Key ZMZDMBWJUHKJPS REWHXWOFAXSMILES S C NPropertiesChemical formula SCN Molar mass 58 08 g mol 1Except where otherwise noted data are given for materials in their standard state at 25 C 77 F 100 kPa N verify what is Y N Infobox references Thiocyanate is analogous to the cyanate ion OCN wherein oxygen is replaced by sulfur SCN is one of the pseudohalides due to the similarity of its reactions to that of halide ions Thiocyanate used to be known as rhodanide from a Greek word for rose because of the red colour of its complexes with iron Thiocyanate is produced by the reaction of elemental sulfur or thiosulfate with cyanide 8 CN S 8 8 SCN displaystyle ce 8 CN S8 gt 8 SCN CN S 2 O 3 2 SCN SO 3 2 displaystyle ce CN S2O3 2 gt SCN SO3 2 The second reaction is catalyzed by thiosulfate sulfurtransferase a hepatic mitochondrial enzyme and by other sulfur transferases which together are responsible for around 80 of cyanide metabolism in the body 2 Contents 1 Biological chemistry of thiocyanate in medicine 2 Coordination chemistry 2 1 Test for iron III and cobalt II 3 See also 4 References 4 1 CitationsBiological chemistry of thiocyanate in medicine editThiocyanate 3 is known to be an important part in the biosynthesis of hypothiocyanite by a lactoperoxidase 4 5 6 Thus the complete absence of thiocyanate or reduced thiocyanate 7 in the human body e g cystic fibrosis is damaging to the human host defense system 8 9 Thiocyanate is a potent competitive inhibitor of the thyroid sodium iodide symporter 10 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 11 In the early 20th century thiocyanate was used in the treatment of hypertension but it is no longer used because of associated toxicity 12 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 with thiosulfate to form the metabolite thiocyanate Thiocyanate is also a metabolite of the detoxification of cyanides by Rhodanese Coordination chemistry edit nbsp Structure of Pd Me2N CH2 3PPh2 SCN NCS 13 S C N S C N displaystyle ce S C N ominus lt gt ominus S C ce N nbsp 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 gt SCN or SCN lt 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 14 It SCN is considered as a weak ligand NCS is a strong ligand 15 Test for iron III and cobalt II edit nbsp nbsp The blood red colored up complex Fe NCS H2O 5 2 left indicates the presence of Fe3 in solution If SCN is added to a solution with iron III ions a blood red solution forms mainly due to the formation of Fe SCN 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 16 Similarly Co2 gives a blue complex with thiocyanate 17 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 18 Phospholipids or some detergents aid the transfer of thiocyanatoiron into chlorinated solvents like chloroform and can be determined in this fashion 19 See also editSulphobesReferences editGreenwood Norman N Earnshaw Alan 1997 Chemistry of the Elements 2nd ed Butterworth Heinemann ISBN 978 0 08 037941 8 Citations edit International Union of Pure and Applied Chemistry 2014 Nomenclature of Organic Chemistry IUPAC Recommendations and Preferred Names 2013 The Royal Society of Chemistry pp 784 1069 doi 10 1039 9781849733069 ISBN 978 0 85404 182 4 Abraham Klaus Buhrke Thorsten Lampen Alfonso 24 February 2015 Bioavailability of cyanide after consumption of a single meal of foods containing high levels of cyanogenic glycosides a crossover study in humans Archives of Toxicology 90 3 559 574 doi 10 1007 s00204 015 1479 8 PMC 4754328 PMID 25708890 Pedemonte N Caci E Sondo E Caputo A Rhoden K Pfeffer U di Candia M Bandettini R Ravazzolo R Zegarra Moran O Galietta L J 2007 Thiocyanate Transport in Resting and IL 4 Stimulated Human Bronchial Epithelial Cells Role of Pendrin and Anion Channels Journal of Immunology 178 8 5144 5153 doi 10 4049 jimmunol 178 8 5144 PMID 17404297 Conner G E Wijkstrom Frei C Randell S H Fernandez V E Salathe M 2007 The Lactoperoxidase System Links Anion Transport to Host Defense in Cystic Fibrosis FEBS Letters 581 2 271 278 doi 10 1016 j febslet 2006 12 025 PMC 1851694 PMID 17204267 White W E Pruitt K M Mansson Rahemtulla B 1983 Peroxidase Thiocyanate Peroxide Antibacterial System Does not Damage DNA Antimicrobial Agents and Chemotherapy 23 2 267 272 doi 10 1128 aac 23 2 267 PMC 186035 PMID 6340603 Thomas E L Aune T M 1978 Lactoperoxidase Peroxide Thiocyanate Antimicrobial System Correlation of Sulfhydryl Oxidation with Antimicrobial Action Infection and Immunity 20 2 456 463 doi 10 1128 IAI 20 2 456 463 1978 PMC 421877 PMID 352945 Minarowski L Sands D Minarowska A Karwowska A Sulewska A Gacko M Chyczewska E 2008 Thiocyanate concentration in saliva of cystic fibrosis patients PDF Folia Histochemica et Cytobiologica 46 2 245 246 doi 10 2478 v10042 008 0037 0 PMID 18519245 permanent dead link Moskwa P Lorentzen D Excoffon K J Zabner J McCray P B Jr Nauseef W M Dupuy C Banfi B 2007 A Novel Host Defense System of Airways is Defective in Cystic Fibrosis American Journal of Respiratory and Critical Care Medicine 175 2 174 183 doi 10 1164 rccm 200607 1029OC PMC 2720149 PMID 17082494 Xu Y Szep S Lu Z Szep Lu 2009 The antioxidant role of thiocyanate in the pathogenesis of cystic fibrosis and other inflammation related diseases Proceedings of the National Academy of Sciences of the United States of America 106 48 20515 20519 Bibcode 2009PNAS 10620515X doi 10 1073 pnas 0911412106 PMC 2777967 PMID 19918082 a href Template Cite journal html title Template Cite journal cite journal a CS1 maint multiple names authors list link Braverman L E He X Pino S et al 2005 The effect of perchlorate thiocyanate and nitrate on thyroid function in workers exposed to perchlorate long term J Clin Endocrinol Metab 90 2 700 706 doi 10 1210 jc 2004 1821 PMID 15572417 Hypothyroidism umm edu University of Maryland Medical Center Retrieved 3 December 2014 Warren F Gorman Emanuel Messinger And Morris Herman 1949 Toxicity of Thiocyanates Used in Treatment of Hypertension Ann Intern Med 30 5 1054 1059 doi 10 7326 0003 4819 30 5 1054 PMID 18126744 Palenik Gus J Clark George Raymond 1970 Crystal and molecular structure of isothiocyanatothiocyanato 1 diphenylphosphino 3 dimethylaminopropane palladium II Inorganic Chemistry 9 12 2754 2760 doi 10 1021 ic50094a028 ISSN 0020 1669 Greenwood p 326 coordination compounds PDF Greenwood p 1090 Uri N 1947 01 01 The stability of the cobaltous thiocyanate complex in ethyl alcohol water mixtures and the photometric determination of cobalt Analyst 72 860 478 481 Bibcode 1947Ana 72 478U doi 10 1039 AN9477200478 PMID 18917685 Kolthoff I M 1930 The Cobalt Thiocyanate Reaction for the Detection of Cobalt and Thiocyanate Mikrochemie 8 S1 176 181 doi 10 1007 BF02759120 ISSN 0369 0261 Stewart J C 1980 Colorimetric determination of phospholipids with ammonium ferrothiocyanate Anal Biochem 104 1 10 14 doi 10 1016 0003 2697 80 90269 9 PMID 6892980 Retrieved from https en 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