Sulfanyl

For the chemistry of organo thiyl radicals, see Thiol#Thiyl radicals.

Sulfanyl
Systematic name Sulfanyl[1] (substitutive) Hydridosulfur(•)[1] (additive)
Other names λ1-Sulfane[2]
Identifiers
CAS number	13940-21-1 Y
PubChem	5460613
ChemSpider	4574111 Y
ChEBI	CHEBI:29312 Y
Gmelin Reference	299
Jmol-3D images	Image 1
SMILES [SH]
InChI InChI=1S/HS/h1H Y Key: PXQLVRUNWNTZOS-UHFFFAOYSA-N Y
Properties
Molecular formula	HS•
Molar mass	33.073 g mol-1
Exact mass	32.979895722 g mol-1
Appearance	Yellow gas[3]
Solubility in water	Reacts
Thermochemistry
Std enthalpy of formation ΔfHo298	139.33 kJ mol-1
Standard molar entropy So298	195.63 J K-1 mol-1
Related compounds
Related radicals	Hydroxyl
Related compounds	Hydrogen sulfide Hydrogen disulfide
Y (verify) (what is: Y/N?) Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa)
Infobox references

Sulfanyl (HS^•) also known as the mercapto radical, hydrosulfide radical, or hydridosulfur, is a simple radical molecule consisting of one hydrogen and one sulfur atom. The radical appears in metabolism in organisms as H₂S is detoxified. Sulfanyl is one of the top three sulfur containing gasses in gas giants such as Jupiter and is very likely to be found in brown dwarfs and cool stars. It was originally discovered by Margaret N. Lewis and John U. White at University of California in 1939.^[4] They observed molecular absorption bands around 325 nm belonging to the system designated by ²Σ⁺ ← ²Π_i. They generated the radical by means of a radio frequency discharge in hydrogen sulfide.^[5] HS* is formed during the degradation of hydrogen sulfide in the atmosphere of the Earth. This may be a deliberate action to destroy odours or a natural phenomena.^[6]

Natural occurrence

Absorption lines of sulfanyl in space were first detected in the infrared by Yamamura in 2000 in a star R And. In the sun SH was detected at several ultraviolet wavelengths: 326.0459 327.5468 328.9749 330.0892 and 330.1112 nm.^[7]

Sulfanyl has been detected in interstellar gas.^[8]

It is possibly present in comets.^[9]

Various theoretical studies have examined HS in atmospheres. In Earth's atmosphere HS reacts with NO₂ to make two products HSNO₂ and HSONO. HSONO decomposes to HSO and NO Also HS reacts with O₂ and N₂O.^[10] HS can also react with Cl₂ producing HSCl and a Cl. atom.^[11] HS* destroys ozone producing HSO* and oxygen.^[12] HS* is formed in the Earth's atmosphere by the reaction of HO*, the hydroxyl radical, on carbon disulfide, carbon oxysulfide and hydrogen sulfide and side products of carbon dioxide and water. Photodissociation of hydrogen sulfide also produces the radical in air.^[13]

In an atmosphere that contains H₂S, HS will be formed if the temperature and pressure are high enough. The ratio of H₂S and HS is given by: log(XH₂S/XHS)=-3.37+8785/T+0.5log P_T+0.5 log X_H2 For a hydrogen dominated atmosphere in a gas giant or star: H₂S has the same level as HS at log P_T = 6.82-17570/T. At higher temperatures HS breaks up into sulfur vapour and H₂. The line of equal S and HS concentration follows the line log P_T = 4.80 - 14522/T. The lines of equal concentration cross at 1509K and 1.51 Pa, with HS being left out of the mix at lower temperatures and pressures. SH is expected to be the second or third most common sulfur containing gas in gas giants or brown dwarfs.^[14]

Formation

Thermal decompostion of mercaptans, such as ethyl mercaptan yields HS^•.^[15]

The radical can be formed by the action of ultraviolet radiation on hydrogen sulfide, which splits off a hydrogen atom. A wavelength of 190 nm gives maximum absorption.^[16]

In humans superoxide dismutase [Cu-Zn] converts the hydrosulfide ion (HS⁻) to HS^•. This happens as the Cu²⁺ ion in the enzyme is converted to Cu⁺.^[17]

Sulfide dehydrogenase as found in sulfur bacteria catalyses the oxidation of HS⁻ to HS^•, by removing a single electron.^[18]

When sulfur minerals are leached with ferric ions HS· is formed in this way: MS + Fe³⁺ + 2H⁺ → M²⁺ + Fe²⁺ + H₂S·⁺ with the H₂S·⁺ radical then passing a proton to water to make the HS· radical. M is a metal such as zinc or copper.^[19] This has potential for bioleaching in metallic ore extraction.

The hydrosulfide ion HS^- can be oxidized to HS* with cerium (IV) sulfate.^[20]

Reactions

Being a radical HS* is quite reactive. In water HS can react with O₂ producing SO₂^- and H⁺. SO₂^- reacts further with O₂ to make SO₂ and superoxide O₂^-. In water HS has an equilibrium with S^- and H⁺. The hydroxyl radical *OH combines with H₂S to form HS* and water.^[21] Other reactions investigated by J. J. Tiee in 1981 are HS·+ethylene, HS·+O₂→HO·+SO, and reactions with itself HS· + HS· → H₂S₂ or H₂ and S.^[22] The disulfide can further react with HS· to make the disulfide radical HSS· and H₂S.^[19]

Properties

The ionization energy of HS is 10.4219 eV.^[23] The reduction potential to go to HS^- is 0.92 eV.^[24] HS* in water can ionize to S*^- and H⁺. The S*^- can catalyze a cis-trans conversion in lipids.^[25]

The interatomic distance between sulfur and hydrogen in the radical is 0.134 nm.^[26]

HS* reacts with carboxylic acids to make carbonyl sulfide (COS) and probably is the main source of this substance in the atmosphere of Earth.^[20]

Related molecules

HSS* is called disufanyl with lengthening chains as trisulfanyl, tetrasulfanyl and pentasulfanyl HSSSSS*. S^-* is termed sufanidyl. HS⁺ is known as sulfanylium, and the common hydrosulfide ion HS_- is also known as sulfanido for a ligand or sulfanide as an anion. Further down the periodic table, HSe* is known as selanyl, and HTe* is termed tellanyl.

References

1. ^ ^{a b} "sulfanyl (CHEBI:29312)". Chemical Entities of Biological Interest. UK: European Bioinformatics Institute. 6 November 2006. Main. http://www.ebi.ac.uk/chebi/searchId.do?chebiId=CHEBI:29312. Retrieved 8 October 2011. 
2. ^ "mercapto radical - Compound Summary". PubChem Compound. USA: National Center for Biotechnology Information. 16 September 2004. Identification and Related Records. http://pubchem.ncbi.nlm.nih.gov/summary/summary.cgi?cid=5460613&loc=ec_rcs. Retrieved 12 October 2011. 
3. ^ Zahnle, Kevin; Mark S. Marley, R. S. Freedman, K. Lodders and J. J. Fortney (26 June 2009). "Atmospheric Sulfur Photochemistry on Hot Jupiters". http://arxiv.org/PS_cache/arxiv/pdf/0903/0903.1663v2.pdf. Retrieved 13 October 2011. 
4. ^ Lewis, Margaret; John U. White (1939). "The Band Spectrum of HS". Physics Reviews (The American Physical Society) 55 (10): 894–898. doi:10.1103/PhysRev.55.894. 
5. ^ Harrison, Jeremy J.; Bryce E. Williamson (November 2005). "Magnetic circular dichroism of the mercapto radical in noble-gas matrices" (in English). Journal of the Indian Institute of Science (Indian Institute of Science) 85: 391–402. http://journal.library.iisc.ernet.in/vol200506/paper6/391-402.pdf. 
6. ^ Mercado-Cabrera, Antonio; B. Jaramillo-Sierra, S.R. Barocio1, R. Valencia-Alvarado, M. Pacheco-Pacheco, R. Peña-Eguiluz, R. Lopez-Callejas, A. Muñoz-Castro, A. De la Piedad-Beneitez (29 April 2009). "Environmental odour control by atmospheric dielectric barrier discharge". ISPC. http://www.ispc-conference.org/ispcproc/papers/275.pdf. Retrieved 20 October 2011. 
7. ^ Sveta V. Berdyugina and W. C. Livingston (May 2002). "Mercapto radical in the solar atmosphere". Astronomy and Astrophysics 387 (1). 
8. ^ Palca, Joe (1 October 2011). "Flying Telescope Makes An Out-Of-This-World Find". NPR. http://www.npr.org/2011/10/01/140877924/flying-telescope-makes-an-out-of-this-world-find. Retrieved 8 October 2011. 
9. ^ "The Cosmic Ice Laboratory - Cometary Molecules". http://science.gsfc.nasa.gov/691/cosmicice/cometary.html. 
10. ^ Resende, Stella M. (2007). "The Atmospheric Oxidation of the HS Radical: Reaction with NO2". Journal of Atmospheric Chemistry 56 (1): 21–32. doi:10.1007/s10874-006-9040-z. 
11. ^ Resende, Stella M.; Fernando R Ornellas (25 February 2000). "Atmospheric reaction between the HS radical and chlorine". Chemical Physics Letters 318 (4-5): 340–344. doi:10.1016/S0009-2614(00)00019-1. 
12. ^ Yoshimura, Yasunori; Toshio Kasai, Hiroshi Ohoyama and Keiji Kuwata (1995). "Nascent HF+ and HSO(2A') Formations in the Elementary Reactions of F + H2S and HS + O3 and the Internal Energy Distributions". Canadian Journal of Chemisty 73: 204–221. http://www.nrcresearchpress.com/doi/pdf/10.1139/v95-029. 
13. ^ Furones, Maikel Yusat Ballester (2008). "A theoretical study on the HSO₂ molecular system" (in English). Coimbra: Universidade de Coimbra. pp. 1, 37. https://estudogeral.sib.uc.pt/jspui/bitstream/10316/7489/3/thesis-MYBF.pdf. Retrieved 20 October 2011. 
14. ^ Visscher, Channon; Katharina Lodders , and Bruce Fegley, Jr. (10 September 2006). "Atmospheric Chemistry in Giant Planets, Brown Dwarfs, and Low-Mass Dwarf Stars. II. Sulfur and Phosphorus". The Astrophysical Journal (The American Astronomical Society) 648: 1181–1195. http://iopscience.iop.org/0004-637X/648/2/1181/63994.text.html. 
15. ^ Sehon, A. H.; B. deB. Darwent (October 1954). "The Thermal Decomposition of Mercaptans". Journal of the Americal Chemical Society 76 (19). doi:10.1021/ja01648a011. 
16. ^ Hollaender, Alexander; Livingston, Robert (1955). "1". Radiation Biology. McGraw Hill. p. 27. http://www.archive.org/stream/radiationbiology02holl/radiationbiology02holl_djvu.txt. 
17. ^ Lyons, Thomas J.; Edith Butler Gralla, and Joan Selverstone Valentine (1999). Biological Chemistry of Copper-Zinc Superoxide Dismutase and Its Link to Amyotrophic Lateral Sclerosis. Basel, Switzerland: Marcel Decker Inc. p. 139. ISBN 0-8247-1956-5. http://www.ffame.org/tlyons/mibs36.125-177.pdf. Retrieved 10 October 2011. 
18. ^ Sorokina, Dimitry Yu; Govardus A.H de Jong, Lesley A Robertson, Gijs J Kuenen (1 May 1998). "Purification and characterization of sulfide dehydrogenase from alkaliphilic chemolithoautotrophic sulfur-oxidizing bacteria". Febs Letters (Elsevier) 427 (1): 11–14. 
19. ^ ^{a b} Schippers, Axel; Wolfgang Sand (January). "Bacterial Leaching of Metal Sulfides Proceeds by Two Indirect Mechanisms via Thiosulfate or via Polysulfides and Sulfur". Applied and Environmental Microbiology (American Society for Microbiology) 65 (1): 319–321. http://aem.asm.org/cgi/reprint/65/1/319.pdf. 
20. ^ ^{a b} Pos, Willer H.; Daniel D. Riemer, Rod G. Zika (1998). "Carbonyl sulfide (OCS) and carbon monoxide (CO) in natural waters: evidence of a coupled production pathway". Marine Chemistry 62: 89–101. 
21. ^ Fang, Hao Jie; Dong Wen Bo, Zhang Ren Xi and Hou, Hui Qi (June 2006). "水相中·HS 的光谱表征及其与氧气的反应研究 Spectrum of·HS and Its Reactions with Oxygen in Aqueous Solution" (in Chinese). Acta Physico Chimica Sinica 22 (6): 761–763. http://www.whxb.pku.edu.cn/EN/abstract/abstract22924.shtml. Retrieved 12 October 2011. 
22. ^ Tiee, J. J.. "Spectroscopy and reaction kinetics of HS radicals". Kinetics database. NIST. http://kinetics.nist.gov/kinetics/Detail?id=1981TIE/WAM80:0. Retrieved 13 October 2011. 
23. ^ Cheng, B. M.; E. P. Chew, W. C. Hung, J. Eberhard and Y. P. Lee (May 1998). "Photoionization studies of sulfur radicals and products of their reactions". Journal of Synchrotron Radiation 5 (3). doi:10.1107/S0909049597016075. 
24. ^ Das, T. N.; R. E. Huie, P. Neta, and S. Padmaja (11 June 1999). "Reduction Potential of the Sulfhydryl Radical:  Pulse Radiolysis and Laser Flash Photolysis Studies of the Formation and Reactions of ·SH and HSSH·- in Aqueous Solutions". The Journal of Physical Chemistry A 103 (27): 5221–5226. doi:10.1021/jp9907544. 
25. ^ Lykakis, Ioannis N.; Carla Ferreri, Chryssostomos Chatgilialoglu (19 January 2007). "The Sulfhydryl Radical (HS./S.−): A Contender for the Isomerization of Double Bonds in Membrane Lipids". Angewandte Chemie (Wiley) 46 (11): 1914–1916. doi:10.1002/anie.200604525. 
26. ^ Ellingson, Benjamin A.; Donald G. Truhlar (1 August 2007). "Explanation of the Unusual Temperature Dependence of the Atmospheric Important OH + H2S → H2O + SH Reaction and Prediction of the Rate Constant at Combustion Temperatures". p. 5. http://static.msi.umn.edu/rreports/2007/267.pdf. Retrieved 20 October 2011. 

External links

• Mercapto radical from NIST
• Milan, J. B.; W. J. Buma, and C. A. de Lange (22 October 1996). "Two-photon resonance enhanced multiphoton ionization photoelectron spectroscopy of the SH (SD) radical below and above the lowest ionization threshold". Journal of Chemical Physics (American Institute of Physics) 105 (16): 6688–6712. http://dare.uva.nl/document/10542. Retrieved 11 October 2011. 
• Burma, W.J.; J. B. Milan;C.A. de Lange;C. M. Western.;N.M.R. Ashfold (1995). "Two-photon resonance enhanced MPI-PES above the lowest ionization threshold: observation of the [a E¹delta5p pi E²phi state of the SH (SD) radical"]. Chemical Physics Letters 239 (4-6): 326–331. http://dare.uva.nl/record/129549.