triethylphosphine
{{Chembox
| ImageFile1 = PEt3.png
| ImageSize1 =
| ImageAlt1 =
| ImageFile2 = Triethylphosphine-from-xtal-view-1-3D-bs-17.png
| PIN = Triethylphosphane
| OtherNames =
|Section1={{Chembox Identifiers
| CASNo = 554-70-1
| PubChem = 27365
| EC_number = 209-068-8
| UNII = 5W435D16PM
| ChemSpiderID = 25463
| ChEBI = 39971
| Gmelin = 2485
| StdInChI=1S/C6H15P/c1-4-7(5-2)6-3/h4-6H2,1-3H3
| StdInChIKey = RXJKFRMDXUJTEX-UHFFFAOYSA-N
| SMILES = CCP(CC)CC
}}
|Section2={{Chembox Properties
| C=6|H=15|P=1
| MolarMass =
| Appearance = colorless liquid
| Density = 0.802 g/cm3
| MeltingPt =
| BoilingPtC = 127-128
| Solubility = }}
|Section3={{Chembox Hazards
| MainHazards =
| FlashPt =
| AutoignitionPt =
| GHSPictograms = {{GHS02}}{{GHS05}}
| GHSSignalWord = Danger
| HPhrases = {{H-phrases|224|225|250|314}}
| PPhrases = {{P-phrases|210|222|233|240|241|242|243|260|264|280|301+330+331|302+334|303+361+353|304+340|305+351+338|310|321|363|370+378|403+235|405|422|501}}
}}
}}
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.
Structure and simple reactions
It is a pyramidal molecule with approximate C3v symmetry.{{ cite journal | title = Trimethylphosphine and Triethylphosphine in the Solid State | first1 = J. | last1 = Bruckmann | first2 = C. | last2 = Krüger | journal = Acta Crystallogr. C | year = 1995 | volume = 51 | issue = 6 | pages = 1155–1158 | doi = 10.1107/S0108270194014368 | doi-access = free | bibcode = 1995AcCrC..51.1155B }}
PEt3 is usually prepared using Grignard reagents:
: 3 CH3CH2MgCl + P(OC6H5)3 → P(CH2CH3)3 + 3 C6H5OMgCl
PEt3 reacts with strong acids to give salts [HPEt3]X.Annette Schier and Hubert Schmidbaur "P-Donor Ligands" in Encyclopedia of Inorganic Chemistry 2006, Wiley-VCH, Weinheim. {{doi|10.1002/0470862106.ia177}} This reaction is reversible. Similarly, it is also easily alkylated to give phosphonium derivatives. PEt3 is easily oxidised to the phosphine oxide with oxygen.
Coordination chemistry
Triethylphosphine is a highly basic ligand that forms coordination complexes with many metals. As a ligand, triethylphosphine's Tolman cone angle is 132°.G. L. Miessler and D. A. Tarr Inorganic Chemistry, 3rd Ed, Pearson/Prentice Hall publisher, {{ISBN|0-13-035471-6}}. Being a relatively compact phosphine, several can bind to a single transition metal, as illustrated by the existence of Pt(PEt3)4.{{cite book|chapter=Tetrakis(Triethylphosphine)Platinum(0)|first1=T.|last1=Yoshida|first2=T.|last2=Matsuda|first3= S.|last3=Otsuka|title=Inorganic Syntheses |volume=28|year=1990|page=122|doi=10.1002/9780470132593.ch32 |isbn=978-0-470-13259-3 }} As a phosphine ligand, triethylphosphine gained acceptance earlier than did the simpler trimethylphosphine, as illustrated by the preparation of the hydride complex trans-PtHCl(PEt3)2.{{cite journal|title=Hydride Complexes|author=Joseph Chatt|journal=Science|year=1968|volume=160|issue=3829 |pages=723–729|doi=10.1126/science.160.3829.723|pmid=17784306|bibcode=1968Sci...160..723C |s2cid=22350909 }}
Safety
PEt3 is toxic. It converts to a low toxicity phosphine oxide upon treatment with sodium hypochlorite or hydrogen peroxide.