Trimethylarsine

Chembox new
ImageFile = Trimethylarsine-2D.png ImageSize = 200px
ImageName = Structural formula of trimethylarsine
ImageFile1 = Trimethylarsine-3D-balls.png ImageSize1 = 200px
ImageName1 = Ball-and-stick model of arsine
IUPACName = trimethanidoarsenic, trimethylarsane
OtherNames = Gosio Gas
Section1 = Chembox Identifiers
CASNo = 593-88-4
RTECS = CH8800000
Section2 = Chembox Properties
Formula = C₃H₉As
MolarMass = 120.02 g/mol
Appearance = Colorless liquid
Density = 1.124 g/cm³
Solubility = Slightly soluble
Solvent = other solvents
SolubleOther = organic solvents
MeltingPt = -87.3 °C
BoilingPt = 51 °C
Section3 = Chembox Structure
Coordination = Trigonal pyramidal
Dipole = 0.86 D
Section7 = Chembox Hazards
ExternalMSDS = [http://www.strem.com/code/datasheets/333750.pdf External MSDS]
MainHazards = Flammable
FlashPt = 100 °C
RPhrases =
SPhrases =
See www.sigmaaldrich.com
Section8 = Chembox Related
OtherCpds = Cacodylic acid
Triphenylarsine

Trimethylarsine is the chemical compound with the formula (CH₃)₃As, commonly abbreviated AsMe₃. This organic derivative of arsine has been used as a source of arsenic in microelectronics industry, [cite journal | author=Hoshino, Masataka | title=A mass spectrometric study of the decomposition of trimethylarsine (TMAs) with triethylgallium (TEGa) |journal=Journal of Crystal Growth 110(1991)704-712 |year=1991 | doi=10.1016/0022-0248(91)90627-H | volume=110 | pages=704] a building block to other organoarsenic compounds, and serves as a ligand in coordination chemistry. It has distinct "garlic"-like smell. Trimethylarsine had been discovered as early as 1854.

tructure and Preparation

As predicted by VSEPR theory, AsMe₃ is a pyramidal molecule. The As-C distances average 1.519 Å, and the C-As-C angles are 91.83° [cite book | author=Wells, A.F. | title=Structural Inorganic Chemistry, fifth edition | publisher=Oxford University Press |year=1984 |id= ISBN-10: 0198553706]

Trimethylarsine can be prepared by treatment of arsenic oxide with trimethylaluminium: [V. V. Gavrilenko, L. A. Chekulaeva, and I. V. Pisareva, "Highly efficient synthesis of trimethylarsine" Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 8, pp. 2122–2123, 1996.] :As₂O₃ + 1.5 [AlMe₃] ₂ → 2 AsMe₃ + 3/n (MeAl-O)_n

Properties and reactions

Trimethylarsine is pyrophoric due to the exothermic nature of the following reaction, which initiates combustion::AsMe₃ + 1/2 O₂ → OAsMe₃ (TMAO)

History

Poisoning events due to a gas produced by certain micobes was assumed to be associated with the arsenic in paint. In 1893 the Italian physician Bartolomeo Gosio published his results on "Gosio gas" that was subsequently shown to contain trimethylarsine. [cite journal
author= Frederick Challenger
title = Biological methylation
journal = Q. Rev. Chem. Soc.
year = 1955
volume = 9
issue =
pages = 255–286
doi = 10.1039/QR9550900255 ] . Under wet conditions, the mold Scopulariopsis brevicaulis produces significant amounts of methyl arsines via methylation [cite journal
author= Ronald Bentley and Thomas G. Chasteen
title = Microbial Methylation of Metalloids: Arsenic, Antimony, and Bismuth
journal = Microbiology and Molecular Biology Reviews
year = 2002
volume = 66
issue = 2
pages = 250–271
doi = 10.1128/MMBR.66.2.250-271.2002 ] of arsenic-containing inorganic pigments, especially Paris green and Scheele's Green, which were once used in indoor wallpapers. Newer studies show that trimethylearsine has a low toxicity and could therefore not account for the death and the severe health problems observed in the 19th century.cite journal
author= William R. Cullen, Ronald Bentley
title = The toxicity of trimethylarsine: an urban myth
journal = J. Environ. Monit.
year = 2005
volume = 7
issue =
pages = 11–15
doi = 10.1039/b413752n ] [cite journal
author= Frederick Challenger, Constance Higginbottom, Louis Ellis
title = The formation of organo-metalloidal compounds by microorganisms. Part I. Trimethylarsine and dimethylethylarsine
journal = J. Chem. Soc.
year = 1933
volume =
issue =
pages = 95–101
doi = 10.1039/JR9330000095 ]

afety

Trimethylarsine is potentially hazardous, [cite journal | author=Andrewes, Paul, et al. | title=Dimethylarsine and Trimethylarsine Are Potent Genotoxins In Vitro |journal=Chem. Res. Toxicol., 16 (8), 994 -1003, 2003. |year=2003] [cite journal | author=Irvin, T.Rick, et al. | title=In-vitro Prenatal Toxicity of Trimethylarsine, Trimethylarsine Oxide and Trimethylarsine Sulfide |journal=Applied Organometallic Chemistry. vol. 9.315-321 |year=1995] [cite journal
author= Hiroshi Yamauchi, Toshikazu Kaise, Keiko Takahashi, Yukio Yamamura
title = Toxicity and metabolism of trimethylarsine in mice and hamsters
journal = Fundamental and Applied Toxicology
year = 1990
volume = 14
issue = 2
pages = 399–407
doi = 10.1016/0272-0590(90)90219-A ] although its toxicity is often overstated.

Importance

Trimethylarsine is the volatile byproduct of microbial action on inorganic forms of arsenic which are naturally occurring in rocks and soils at the parts per million level. [cite journal | author=Cullen, W.R., Reimer, K.J. | title=Arsenic speciation in the environment |journal=Chem. Reviews |volume = 89 | pages = 713–764,|year=1989 | doi=10.1021/cr00094a002] Trimethylarsine as been reported only at trace levels (parts per billion) in landfill gas from Germany, Canada, and the U.S.A., and is the major arsenic-containing compound in the gas. [cite journal | author=Feldmann, J., Cullen, W.R. | title=Occurrence of Volatile Transition Metal Compounds in Landfill Gas: Synthesis of Molybdenum and Tungsten Carbonyls in the |journal=Environ. Sci. Technol.| volume=31 | pages = 2125–2129 |year=1997 | doi=10.1021/es960952y] [cite journal
author= Pinel-Raffaitin, P., LeHecho, I., Amouroux, D., Potin-Gautier, M.
title = Distribution and Fate of Inorganic and Organic Arsenic Species in Landfill Leachates and Biogases
journal = Environ. Sci. Technol.
year = 2007
volume = 41
issue = 13
pages = 4536–4541
doi = 10.1021/es0628506] [cite conference
author= Khoury, J.T. et al.| title = Analysis of Volatile Arsenic Compounds in Landfill Gas
booktitle = Odors & Air Emissions 2008
location = Phoenix, Arizona
date = April 7, 2008
publisher = Water Environment Federation]

References

External links

* [http://lb.chemie.uni-hamburg.de/static/data/48_3vr6vtls.html Index by Molecular Formula]
* [http://people.clarkson.edu/orgs/indhygie/manual/chemhyg.htm Information on Hazardous Chemicals by Class]
* [http://mmbr.asm.org/cgi/content/full/66/2/250?maxtoshow=&HITS=10&...ls.asm.org%2Fcgi%2Fsearch#Gosio%20Gas%20Is%20Trimethylarsine Microbial Methylation of Metalloids: Arsenic, Antimony, and Bismuth]
* [http://chemeducator.org/sbibs/s0007002/spapers/720051rb.htm Arsenic Curiosa and Humanity]