Trimethylphosphine

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Trimethylphosphine
Trimethylphosphine Structural Formula.svg
Trimethylphosphine-A-3D-balls.png
Trimethylphosphine-3D-vdW.png
Names
Preferred IUPAC name
Trimethylphosphane
Systematic IUPAC name
Trimethylphosphane [1] (substitutive)
Trimethylphosphorus [1] (additive)
Identifiers
3D model (JSmol)
969138
ChEBI
ChemSpider
ECHA InfoCard 100.008.932 OOjs UI icon edit-ltr-progressive.svg
EC Number
  • 209-823-1
MeSH trimethyl+phosphine
PubChem CID
UNII
UN number 1993
  • InChI=1S/C3H9P/c1-4(2)3/h1-3H3 X mark.svgN
    Key: YWWDBCBWQNCYNR-UHFFFAOYSA-N X mark.svgN
  • CP(C)C
Properties
C3H9P
Molar mass 76.079 g·mol−1
AppearanceColorless liquid
Density 735 mg cm−3
Melting point −86 °C (−123 °F; 187 K)
Boiling point 38 to 39 °C (100 to 102 °F; 311 to 312 K)
Vapor pressure 49.9 kPa (at 20 °C)
Structure
Trigonal pyramidal
1.19 Debye
Hazards
GHS labelling:
GHS-pictogram-flamme.svg GHS-pictogram-exclam.svg
Danger
H225, H315, H319, H335
P210, P261, P305+P351+P338
Flash point −19 °C (−2 °F; 254 K)
Related compounds
Related compounds
PEt3
NMe3
PH3
PPh3
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
X mark.svgN  verify  (what is  Yes check.svgYX mark.svgN ?)

Trimethylphosphine is an organophosphorus compound with the formula P(CH3)3, commonly abbreviated as PMe3. This colorless liquid has a strongly unpleasant odor, characteristic of alkylphosphines. The compound is a common ligand in coordination chemistry.

Contents

Structure and bonding

It is a pyramidal molecule with approximate C3v symmetry. The C–P–C bond angles are approximately 98.6°. [2]

The C–P–C bond angles are consistent with the notion that phosphorus predominantly uses the 3p orbitals for forming bonds and that there is little sp hybridization of the phosphorus atom. The latter is a common feature of the chemistry of phosphorus. As a result, the lone pair of trimethylphosphine has predominantly s-character as is the case for phosphine, PH3. [3]

PMe3 can be prepared by the treatment of triphenyl phosphite with methylmagnesium chloride: [4]

3 CH3MgCl + P(OC6H5)3 → P(CH3)3 + 3 C6H5OMgCl

The synthesis is conducted in dibutyl ether, from which the more volatile PMe3 can be distilled.

Reactions

Structure of HW(PMe3)4(Me2PCH2), "W(PMe3)5". ZEGTOU01.png
Structure of HW(PMe3)4(Me2PCH2), "W(PMe3)5".

With a pKa of 8.65, PMe3 reacts with strong acids to give salts [HPMe3]X. [2] This reaction is reversible. With strong bases, such as alkyl lithium compounds, a methyl group undergoes deprotonation to give PMe2CH2Li.

PMe3 is easily oxidised to the phosphine oxide with oxygen. It reacts with methyl bromide to give tetramethylphosphonium bromide. [6]

Coordination chemistry

Trimethylphosphine is a highly basic ligand that forms complexes with most metals. As a ligand, trimethylphosphine's Tolman cone angle is 118°. [7] This angle is an indication of the amount of steric protection that this ligand provides to the metal that to which it is bound.

Being a relatively compact phosphine, several can bind to a single transition metal, as illustrated by the existence of Pt(PEt3)4. [8] Its complex with silver iodide, AgI(PMe3) is an air-stable solid that releases PMe3 upon heating.

Safety

PMe3 is toxic and pyrophoric. It converts to a much safer phosphine oxide upon treatment with sodium hypochlorite or hydrogen peroxide. [9]

Related Research Articles

<span class="mw-page-title-main">Phosphonium</span> Family of polyatomic cations containing phosphorus

In chemistry, the term phosphonium describes polyatomic cations with the chemical formula PR+
4
. These cations have tetrahedral structures. The salts are generally colorless or take the color of the anions.

<span class="mw-page-title-main">Triphenylphosphine</span> Chemical compound

Triphenylphosphine (IUPAC name: triphenylphosphane) is a common organophosphorus compound with the formula P(C6H5)3 and often abbreviated to PPh3 or Ph3P. It is versatile compound that is widely used as a reagent in organic synthesis and as a ligand for transition metal complexes, including ones that serve as catalysts in organometallic chemistry. PPh3 exists as relatively air stable, colorless crystals at room temperature. It dissolves in non-polar organic solvents such as benzene and diethyl ether.

Phosphorus trifluoride (formula PF3), is a colorless and odorless gas. It is highly toxic and reacts slowly with water. Its main use is as a ligand in metal complexes. As a ligand, it parallels carbon monoxide in metal carbonyls, and indeed its toxicity is due to its binding with the iron in blood hemoglobin in a similar way to carbon monoxide.

Cycloocta-1,5-diene is a cyclic hydrocarbon with the chemical formula C8H12, specifically [−(CH2)2−CH=CH−]2.

<span class="mw-page-title-main">Phosphine oxides</span> Class of chemical compounds

Phosphine oxides are phosphorus compounds with the formula OPX3. When X = alkyl or aryl, these are organophosphine oxides. Triphenylphosphine oxide is an example. An inorganic phosphine oxide is phosphoryl chloride (POCl3). The parent phosphine oxide (H3PO) remains rare and obscure.

<span class="mw-page-title-main">Tungsten hexacarbonyl</span> Chemical compound

Tungsten hexacarbonyl (also called tungsten carbonyl) is an organometallic compound with the formula W(CO)6. This complex gave rise to the first example of a dihydrogen complex.

Organophosphines are organophosphorus compounds with the formula PRnH3−n, where R is an organic substituent. These compounds can be classified according to the value of n: primary phosphines (n = 1), secondary phosphines (n = 2), tertiary phosphines (n = 3). All adopt pyramidal structures. Organophosphines are generally colorless, lipophilic liquids or solids. The parent of the organophosphines is phosphine (PH3).

<span class="mw-page-title-main">Triphenyl phosphite</span> Chemical compound

Triphenyl phosphite is the organophosphorus compound with the formula P(OC6H5)3. It is a colourless viscous liquid.

<span class="mw-page-title-main">Triethyl phosphite</span> Chemical compound

Triethyl phosphite is an organophosphorus compound, specifically a phosphite ester, with the formula P(OCH2CH3)3, often abbreviated P(OEt)3. It is a colorless, malodorous liquid. It is used as a ligand in organometallic chemistry and as a reagent in organic synthesis.

<span class="mw-page-title-main">Trimethyl phosphite</span> Chemical compound

Trimethyl phosphite is an organophosphorus compound with the formula P(OCH3)3, often abbreviated P(OMe)3. It is a colorless liquid with a highly pungent odor. It is the simplest phosphite ester and finds used as a ligand in organometallic chemistry and as a reagent in organic synthesis. The molecule features a pyramidal phosphorus(III) center bound to three methoxy groups.

<span class="mw-page-title-main">Bis(cyclooctadiene)nickel(0)</span> Chemical compound

Bis(cyclooctadiene)nickel(0) is the organonickel compound with the formula Ni(C8H12)2, also written Ni(cod)2. It is a diamagnetic coordination complex featuring tetrahedral nickel(0) bound to the alkene groups in two 1,5-cyclooctadiene ligands. This highly air-sensitive yellow solid is a common source of Ni(0) in chemical synthesis.

<span class="mw-page-title-main">Dimethylphenylphosphine</span> Chemical compound

Dimethylphenylphosphine is an organophosphorus compound with a formula P(C6H5)(CH3)2. The phosphorus is connected to a phenyl group and two methyl groups, making it the simplest aromatic alkylphosphine. It is colorless air sensitive liquid. It is a member of series (CH3)3-n(C6H5)2P that also includes n = 0, n = 2, and n = 3 that are often employed as ligands in metal phosphine complexes.

<span class="mw-page-title-main">Sodium tetrachloropalladate</span> Chemical compound

Sodium tetrachloropalladate is an inorganic compound with the chemical formula Na2PdCl4. This salt, and the analogous alkali metal salts of the form M2PdCl4, may be prepared simply by reacting palladium(II) chloride with the appropriate alkali metal chloride in aqueous solution. Palladium(II) chloride is insoluble in water, whereas the product dissolves:

Organoplatinum chemistry is the chemistry of organometallic compounds containing a carbon to platinum chemical bond, and the study of platinum as a catalyst in organic reactions. Organoplatinum compounds exist in oxidation state 0 to IV, with oxidation state II most abundant. The general order in bond strength is Pt-C (sp) > Pt-O > Pt-N > Pt-C (sp3). Organoplatinum and organopalladium chemistry are similar, but organoplatinum compounds are more stable and therefore less useful as catalysts.

Organorhenium chemistry describes the compounds with Re−C bonds. Because rhenium is a rare element, relatively few applications exist, but the area has been a rich source of concepts and a few useful catalysts.

<span class="mw-page-title-main">Metal bis(trimethylsilyl)amides</span>

Metal bis(trimethylsilyl)amides are coordination complexes composed of a cationic metal M with anionic bis(trimethylsilyl)amide ligands (the N 2 monovalent anion, or −N 2 monovalent group, and are part of a broader category of metal amides.

<span class="mw-page-title-main">Metal halides</span>

Metal halides are compounds between metals and halogens. Some, such as sodium chloride are ionic, while others are covalently bonded. A few metal halides are discrete molecules, such as uranium hexafluoride, but most adopt polymeric structures, such as palladium chloride.

<span class="mw-page-title-main">Metal-phosphine complex</span>

A metal-phosphine complex is a coordination complex containing one or more phosphine ligands. Almost always, the phosphine is an organophosphine of the type R3P (R = alkyl, aryl). Metal phosphine complexes are useful in homogeneous catalysis. Prominent examples of metal phosphine complexes include Wilkinson's catalyst (Rh(PPh3)3Cl), Grubbs' catalyst, and tetrakis(triphenylphosphine)palladium(0).

<span class="mw-page-title-main">Triethylphosphine</span> Chemical compound

Triethylphosphine is the organophosphorus compound with the formula P(CH2CH3)3, commonly abbreviated as PEt3. It is a colorless liquid with an unpleasant odor characteristic of alkylphosphines. The compound is a common ligand in organometallic chemistry, such as in auranofin.

Rhenium compounds are compounds formed by the transition metal rhenium (Re). Rhenium can form in many oxidation states, and compounds are known for every oxidation state from -3 to +7 except -2, although the oxidation states +7, +4, and +3 are the most common. Rhenium is most available commercially as salts of perrhenate, including sodium and ammonium perrhenates. These are white, water-soluble compounds. The tetrathioperrhenate anion [ReS4] is possible.

References

  1. 1 2 "Trimethylphosphine (CHEBI:35890)". Chemical Entities of Biological Interest (ChEBI). UK: European Bioinformatics Institute. 6 June 2006. IUPAC Names. Retrieved 25 September 2011.
  2. 1 2 Schier, Annette; Schmidbaur, Hubert (2006). "P-Donor Ligands". In Charles A. McAuliffe, Anthony G. Mackie (ed.). Encyclopedia of Inorganic Chemistry, First Edition. doi:10.1002/0470862106.ia177. ISBN   0-470-86078-2.
  3. E. Fluck, The Chemistry of Phosphine, Topics in Current Chemistry Vol. 35, 64 pp, 1973.
  4. Leutkens Jr., M. L.; Sattelberger, A. P.; Murray, H. H.; Basil, J. D.; Fackler J. P. Jr. (1990). "Trimethylphosphine". Inorganic Syntheses. Inorganic Syntheses. Vol. 28. pp. 305–310. doi:10.1002/9780470132593.ch76. ISBN   978-0-470-13259-3.
  5. Sattler, A.; Parkin, G. (2011). "Formation of a Cationic Alkylidene Complex via Formal Hydride Abstraction: Synthesis and Structural Characterization of [W(PMe3)4([η2-CHPMe2)H]X (X = Br, I)". Chemical Communications. 47 (48): 12828–12830. doi:10.1039/C1CC15457E. PMID   22048609.
  6. H. F. Klein (1978). "Trimethylphosphonium Methylide (Trimethyl Methylenephosphorane)". Inorganic Syntheses. Vol. XVIII. pp. 138–140. doi:10.1002/9780470132494.ch23. ISBN   978-0-470-13249-4.
  7. G. L. Miessler and D. A. Tarr Inorganic Chemistry, 3rd Ed, Pearson/Prentice Hall publisher, ISBN   0-13-035471-6.
  8. T. Yoshida; T. Matsuda; S. Otsuka (1990). "Tetrakis(Triethylphosphine)Platinum(0)". Inorganic Syntheses. Vol. 28. pp. 122–123. doi:10.1002/9780470132593.ch32. ISBN   978-0-470-13259-3.
  9. "Trimethylphosphine solution". sigmaaldrich.com. Retrieved 1 August 2023.