Tetramethylphosphonium bromide

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Tetramethylphosphonium bromide
Me4PBr.png
Identifiers
3D model (JSmol)
ChemSpider
ECHA InfoCard 100.152.249 Edit this at Wikidata
UNII
  • InChI=1S/C4H12P.BrH/c1-5(2,3)4;/h1-4H3;1H/q+1;/p-1
    Key: ZTXFOCMYRCGSMU-UHFFFAOYSA-M
  • C[P+](C)(C)C.[Br-]
Properties
C4H12BrP
Molar mass 171.018 g·mol−1
Appearance white solid
Hazards
GHS labelling:
GHS07: Exclamation mark
Warning
H315, H319, H335
P261, P264, P271, P280, P302+P352, P304+P340, P305+P351+P338, P312, P321, P332+P313, P337+P313, P362, P403+P233, P405, P501
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).

Tetramethylphosphonium bromide is an organophosphorus compound with the formula (CH3)4PBr. It is a white, water-soluble solid, the salt of the cation tetramethylphosphonium and the bromide anion. It is prepared by treating trimethylphosphine with methyl bromide.

Reactions[edit]

Structure of Cu2[(Me2P(CH2)2]2.

Deprotonation gives methylenetrimethylphosphine ylide, which can sustain a second deprotonation:[1]

(CH3)4PBr + BuLi → CH3)3P=CH2 + LiBr + BuH
CH3)3P=CH2 + BuLi → CH3)2P(CH2)2Li + BuH

The latter is a precursor to many coordination complexes, e.g., the dicuprous complex Cu2[(Me2P(CH2)2]2.[2]

References[edit]

  1. ^ H. F. Klein (1978). "Trimethylphosphonium Methylide (Trimethyl Methylenephosphorane)". Inorganic Syntheses. XVIII: 138–140. doi:10.1002/9780470132494.ch23.
  2. ^ Schmidbaur, H. (1983). "Phosphorus Ylides in the Coordination Sphere of Transition Metals: An Inventory". Angewandte Chemie International Edition in English. 22 (12): 907–927. doi:10.1002/anie.198309071.