Dimethylphosphine

Dimethylphosphine is the organophosphorus compound with the formula (CH₃)₂PH, often written Me₂PH. It is a malodorous gas that condenses to a colorless liquid just below room temperature. Although it can be produced by methylation of phosphine, a more practical synthesis involves the reduction of tetramethyldiphosphine disulfide with tributylphosphine:^[1]

(CH₃)₂P(S)−P(S)(CH₃)₂ + P((CH₂)₃CH₃)₃ + H₂O → (CH₃)₂PH + SP((CH₂)₃CH₃)₃ + (CH₃)₂P(O)(OH)

Dimethylphosphine

Names
Preferred IUPAC name Dimethylphosphane
Identifiers
CAS Number	676-59-5
3D model (JSmol)	Interactive image
ChemSpider	62810
PubChem CID	69607
UNII	DRV85A28TP Y
CompTox Dashboard (EPA)	DTXSID40217918
InChI InChI=1S/C2H7P/c1-3-2/h3H,1-2H3 Key: YOTZYFSGUCFUKA-UHFFFAOYSA-N
SMILES CPC
Properties
Chemical formula	(CH3)2PH
Molar mass	62.052 g·mol−1
Appearance	Colorless gas or colorless liquid
Odor	Malodorous
Boiling point	21.1 °C
Hazards
Occupational safety and health (OHS/OSH):
Main hazards	toxic
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). Infobox references

Reactions

The compound exhibits the properties characteristic of a secondary phosphine, i.e., a compound of the type R₂PH. It can be oxidized to the phosphinic acid:

(CH₃)₂PH + O₂ → (CH₃)₂P(O)(OH)

It can be protonated to give the dimethylphosphonium ion:

(CH₃)₂PH + H⁺ → [(CH₃)₂PH₂]⁺

With strong bases (e.g., lithium amide, it can be deprotonated to give dimethyl phosphide derivatives (e.g., lithium dimethyl phosphide):

(CH₃)₂PH + LiNH₂ → (CH₃)₂PLi + NH₃