Trimethyl phosphite

Trimethyl phosphite
Names
	IUPAC name Trimethyl phosphite
	Other names Trimethoxyphosphine
Identifiers
CAS Number	121-45-9 ;
3D model (JSmol)	Interactive image;
ChemSpider	8159 ;
ECHA InfoCard	100.004.065
PubChem CID	8472;
CompTox Dashboard (EPA)	DTXSID4026979 ;
	InChI InChI=1S/C3H9O3P/c1-4-7(5-2)6-3/h1-3H3 Key: CYTQBVOFDCPGCX-UHFFFAOYSA-N ; InChI=1/C3H9O3P/c1-4-7(5-2)6-3/h1-3H3 Key: CYTQBVOFDCPGCX-UHFFFAOYAO;
	SMILES O(P(OC)OC)C;
Properties
Chemical formula	C3H9O3P
Molar mass	124.08
Appearance	colorless liquid
Odor	distinctive, pungent
Density	1.052
Melting point	−78 °C (−108 °F; 195 K)
Boiling point	111 °C (232 °F; 384 K)
Solubility in water	reacts
Vapor pressure	24 mmHg (25°C)
Hazards
Flash point	28 °C; 82 °F; 301 K
	NIOSH (US health exposure limits):
PEL (Permissible)	none
REL (Recommended)	TWA 2 ppm (10 mg/m3)
IDLH (Immediate danger)	N.D.
Related compounds
Related compounds	Dimethyl methylphosphonate
	Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). verify (what is ?) Infobox references

Trimethylphosphite is an organophosphorus compound with the formula P(OCH₃)₃, often abbreviated P(OMe)₃. This colorless liquid is used as a ligand in organometallic chemistry and as a reagent in organic synthesis. The material also has a highly pungent smell. The molecule features a pyramidal phosphorus(III) center bound to three methoxy groups.

Synthesis and reactions

Trimethylphosphite is prepared from phosphorus trichloride:

It is susceptible to oxidation to trimethyl phosphate.

It reacts with a catalytic amount of methyl iodide in the Arbuzov reaction to give dimethyl methylphosphonate:

P(OCH₃) → CH₃)P(O)(OCH₂)

As a ligand, trimethylphosphite has a smaller cone angle and better acceptor properties relative to trimethylphosphine. A representative derivative is the colorless, tetrahedral complex Ni(P(OMe)₃)₄ (m.p. 108 °C).^[2] The tridentate ligand called the Klaui ligand is derived from trimethylphosphite. The formation of this ligand illustrates the susceptibility of trimethylphosphite (and metal complexes thereof) to the Arbuzov reaction.

Trimethylphosphite is also used as a mild desulfurization reagent in organic synthesis, for example in the preparation of derivatives of tetrathiafulvalene.^[3]

Toxicity

The LD50 is 1600–2890 mg/kg (oral, rat).^[4]

References

^ ^a ^b ^c ^d ^e ^f ^g NIOSH Pocket Guide to Chemical Hazards. "#0640". National Institute for Occupational Safety and Health (NIOSH).
^ Ittel, Steven D.; Ittel, S. D.; Cushing, M. A. (1990). "Complexes of Nickel(0)". Inorganic Syntheses. Inorganic Syntheses. 28: 98–104. doi:10.1002/9780470132593.ch25. ISBN 978-0-471-52619-3.
^ Jan Larsen and Christine Lenoir (1998). "2,2'-Bi-5,6-Dihydro-1,3-Dithiolo[4,5-b][1,4]dithiinylidene (BEDT-TTF)". Organic Syntheses; Collected Volumes, vol. 9, p. 72..
^ Svara, J.; Weferling, N.; Hofmann, T. "Phosphorus Compounds, Organic". Ullmann's Encyclopedia of Industrial Chemistry. Weinheim: Wiley-VCH. doi:10.1002/14356007.a19_545.pub2. ISBN 978-3527306732.{{cite encyclopedia}}: CS1 maint: multiple names: authors list (link)

External links

[PGCH-1] ^ ^a ^b ^c ^d ^e ^f ^g NIOSH Pocket Guide to Chemical Hazards. "#0640". National Institute for Occupational Safety and Health (NIOSH).

[2] Ittel, Steven D.; Ittel, S. D.; Cushing, M. A. (1990). "Complexes of Nickel(0)". Inorganic Syntheses. Inorganic Syntheses. 28: 98–104. doi:10.1002/9780470132593.ch25. ISBN 978-0-471-52619-3.

[3] Jan Larsen and Christine Lenoir (1998). "2,2'-Bi-5,6-Dihydro-1,3-Dithiolo[4,5-b][1,4]dithiinylidene (BEDT-TTF)". Organic Syntheses; Collected Volumes, vol. 9, p. 72..

[Svara-4] Svara, J.; Weferling, N.; Hofmann, T. "Phosphorus Compounds, Organic". Ullmann's Encyclopedia of Industrial Chemistry. Weinheim: Wiley-VCH. doi:10.1002/14356007.a19_545.pub2. ISBN 978-3527306732.{{cite encyclopedia}}: CS1 maint: multiple names: authors list (link)

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