Selenophene

Selenophene
Names
	Preferred IUPAC name Selenophene
Identifiers
CAS Number	288-05-1;
Beilstein Reference	103223
ChEBI	CHEBI:30857;
ChemSpider	119907;
ECHA InfoCard	100.157.009
Gmelin Reference	100994
PubChem CID	136130;
CompTox Dashboard (EPA)	DTXSID20182978 ;
	InChI InChI=1S/C4H4Se/c1-2-4-5-3-1/h1-4H Key: MABNMNVCOAICNO-UHFFFAOYSA-N;
	SMILES C1=C[Se]C=C1;
Properties
Chemical formula	C4H4Se
Molar mass	131.047 g·mol−1
Density	1.52
Melting point	−38 °C (−36 °F; 235 K)
Boiling point	110 °C (230 °F; 383 K)
Refractive index (nD)	1.58
Hazards
	GHS labelling:
Pictograms
Signal word	Danger
Hazard statements	H225, H301, H331, H373, H410
Precautionary statements	P210, P233, P240, P241, P242, P243, P260, P261, P264, P270, P271, P273, P280, P301+P310, P303+P361+P353, P304+P340, P311, P314, P321, P330, P370+P378, P391, P403+P233, P403+P235, P405, P501
Related compounds
Related more saturated	selenolane; 2-selenolene; 3-selenolene
Related compounds	furan; thiophene; tellurophene
	Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). Infobox references

Selenophene is an unsaturated organic compound containing a five member ring with selenium with formula C₄H₄Se. It is a metallole with reduced aromatic character compared to thiophene.

Nomenclature

Atoms in selenophene are numbered sequentially around the ring, starting with the selenium atom as number 1 following normal systematic nomenclature rules. Oxidized forms include selenophene 1,1-dioxide.^[2] Related ring structures include those with only one double bond (2-selenolene and 3-selenolene) and the fully saturated structure selenolane.^[3]

Production

Although Ida Foa claimed to have made selenophene in 1909, the first confirmed production was by Mazza and Solazzo in 1927. They heated acetylene and selenium together at about 300 °C. The selenium burst into flame, and up to 15% selenophene was formed, along with selenonaphthene.^[3] Another way to make it is from furan heated with hydrogen selenide and aluminium at 400 °C.^[4]

Substituted selenophenes can be made using a Fiesselman procedure in which a β-chloro-aldehyde reacts with sodium selenide, and then ethyl bromoacetate.^[4]

Properties

The selenophene molecule is flat and aromatic.^[4] Being aromatic, it undergoes electrophilic substitution reactions at the 2- or 2,5-positions.^[4] These reactions are slower than that of furan, but faster than thiophene.^[4]

References

^ International Union of Pure and Applied Chemistry (2014). Nomenclature of Organic Chemistry: IUPAC Recommendations and Preferred Names 2013. The Royal Society of Chemistry. p. 141. doi:10.1039/9781849733069. ISBN 978-0-85404-182-4.
^ Pelkey, E. T. (2008). Katritzky, Alan R.; Ramsden, Christopher A.; Scriven, Eric F. V.; Taylor, Richard J. K. (eds.). Comprehensive Heterocyclic Chemistry III. Oxford: Elsevier. pp. 975–1006. doi:10.1016/B978-008044992-0.00313-8. ISBN 9780080449920.
^ ^a ^b Hartough, H. D. (2009). Thiophene and Its Derivatives. John Wiley & Sons. ISBN 9780470188026.
^ ^a ^b ^c ^d ^e Eicher, Theophil; Hauptmann, Siegfried; Speicher, Andreas (2013). The Chemistry of Heterocycles: Structures, Reactions, Synthesis, and Applications. John Wiley & Sons. pp. 69–70. ISBN 9783527669868.

[1] International Union of Pure and Applied Chemistry (2014). Nomenclature of Organic Chemistry: IUPAC Recommendations and Preferred Names 2013. The Royal Society of Chemistry. p. 141. doi:10.1039/9781849733069. ISBN 978-0-85404-182-4.

[2] Pelkey, E. T. (2008). Katritzky, Alan R.; Ramsden, Christopher A.; Scriven, Eric F. V.; Taylor, Richard J. K. (eds.). Comprehensive Heterocyclic Chemistry III. Oxford: Elsevier. pp. 975–1006. doi:10.1016/B978-008044992-0.00313-8. ISBN 9780080449920.

[taid-3] Hartough, H. D. (2009). Thiophene and Its Derivatives. John Wiley & Sons. ISBN 9780470188026.

[tcah-4] Eicher, Theophil; Hauptmann, Siegfried; Speicher, Andreas (2013). The Chemistry of Heterocycles: Structures, Reactions, Synthesis, and Applications. John Wiley & Sons. pp. 69–70. ISBN 9783527669868.

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