Pentamethyl arsenic

Structural formula
General
Surname	Pentamethyl arsenic
Molecular formula	C 5 H 15 As
Brief description	colorless liquid
External identifiers / databases
PubChem	9548862
Wikidata	Q2069338
properties
Molar mass	150.1 g mol −1
Melting point	−6 to −7 ° C
boiling point	> 100 ° C (decomposition)
solubility	easily soluble in hydrocarbons and ethers
safety instructions
H and P phrases	H: 331-301-410
	P: ?
	As far as possible and customary, SI units are used. Unless otherwise noted, the data given apply to standard conditions .

Pentamethyl arsenic is an organometallic compound of arsenic and is a colorless, toxic liquid at room temperature .

history

Pentamethyl arsenic was first synthesized in 1973 by Karl-Heinz Mitschke and Hubert Schmidbaur ( University of Würzburg ).

Extraction and presentation

The starting material for the synthesis of pentamethylarsene is trimethylarsine . Trimethylarsene dichloride is obtained from this by reaction with chlorine . If this is reacted with methyl lithium in diethyl ether , pentamethyl arsenic is formed.

{\ displaystyle \ mathrm {Me_ {3} As + Cl_ {2} \ longrightarrow Me_ {3} AsCl_ {2}}}

{\ displaystyle \ mathrm {Me_ {3} AsCl_ {2} +2 \ MeLi \ longrightarrow Me_ {5} As + 2 \ LiCl}}

properties

Pentamethyl arsenic is a colorless, highly volatile liquid that decomposes above 100 ° C. The decomposition produces trimethylarsine, methane and ethene as well as small amounts of ethane . The reaction takes place mainly via an unstable ylid that breaks down into smaller molecules.

The compound is only slightly sensitive to air, but reacts with water, methanol and ethanol . With the elimination of methane, tetramethylarsonium hydroxide or alcoholates are formed.

{\ displaystyle \ mathrm {Me_ {5} As + H_ {2} O \ longrightarrow Me_ {4} AsOH + CH_ {4}}}

As expected from the VSEPR model , pentamethyl arsenic has a trigonal-bipyramidal structure.

Individual evidence

^ AF Holleman , E. Wiberg , N. Wiberg : Textbook of Inorganic Chemistry . 101st edition. Walter de Gruyter, Berlin 1995, ISBN 3-11-012641-9 .
↑ ^a ^b ^c ^d ^e Karl-Heinz Mitschke, Hubert Schmidbaur: Pentamethylarsen . In: Chemical Reports. 1973, 106, 11, pp. 3645-3651.
^ Entry on arsenic compounds in the GESTIS substance database of the IFA , accessed on January 10, 2017(JavaScript required) .
↑ Not explicitly listed in Regulation (EC) No. 1272/2008 (CLP) , but with the specified labeling it falls under the group entry arsenic compounds, with the exception of those named in this appendix in the Classification and Labeling Inventory of the European Chemicals Agency (ECHA) on February 1, 2016. Manufacturers or distributors can expand the harmonized classification and labeling .
↑ Tim M. Greene, Anthony J. Downs, Colin R. Pulham, Arne Haaland, Hans Peter Verne, Hans Vidar Volden, Tatjana V. Timofeeva: Molecular Structures of Pentamethylarsenic (V) and Trimethyldichloroarsenic (V) by Gas Electron Diffraction and ab Initio Calculations: Molecular Mechanics Calculations on Pentamethylarsenic (V), Pentaphenylarsenic (V), and Related Compounds . In: Organometallics 1998, 17, 24, pp. 5287-5293; doi : 10.1021 / om980520r .

literature

Karl-Heinz Mitschke, Hubert Schmidbaur: Pentamethylarsen . In: Chemical Reports. 1973, 106, 11, pp. 3645-3651, doi : 10.1002 / cber.19731061124 .
Christoph Elschenbroich: Organometallic chemistry . 6th edition, Teubner Wiesbaden, 2008, ISBN 978-3-8351-0167-8 , pp. 202-203.

[HoWi-1] AF Holleman , E. Wiberg , N. Wiberg : Textbook of Inorganic Chemistry . 101st edition. Walter de Gruyter, Berlin 1995, ISBN 3-11-012641-9 .

[ChemBer-2] Karl-Heinz Mitschke, Hubert Schmidbaur: Pentamethylarsen . In: Chemical Reports. 1973, 106, 11, pp. 3645-3651.

[GESTIS-3] Entry on arsenic compounds in the GESTIS substance database of the IFA , accessed on January 10, 2017(JavaScript required) .

[CLP_100.240.769-4] Not explicitly listed in Regulation (EC) No. 1272/2008 (CLP) , but with the specified labeling it falls under the group entry arsenic compounds, with the exception of those named in this appendix in the Classification and Labeling Inventory of the European Chemicals Agency (ECHA) on February 1, 2016. Manufacturers or distributors can expand the harmonized classification and labeling .

[5] Tim M. Greene, Anthony J. Downs, Colin R. Pulham, Arne Haaland, Hans Peter Verne, Hans Vidar Volden, Tatjana V. Timofeeva: Molecular Structures of Pentamethylarsenic (V) and Trimethyldichloroarsenic (V) by Gas Electron Diffraction and ab Initio Calculations: Molecular Mechanics Calculations on Pentamethylarsenic (V), Pentaphenylarsenic (V), and Related Compounds . In: Organometallics 1998, 17, 24, pp. 5287-5293; doi : 10.1021 / om980520r .