Tetramethylethylenediamine

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Template:Chembox header | Tetramethylethylenediamine
Tetramethylethylenediamine
Template:Chembox header | General
Systematic name N,N,N',N'-tetramethyl-
ethane-1,2-diamine
Other names TEMED
TMEDA
TMED
1,2-bis(dimethylamino)-
ethane
Molecular formula C6H16N2
SMILES CN(C)CCN(C)C
Molar mass 116.24 g/mol
Appearance colorless liquid
CAS number [110-18-9]
Template:Chembox header | Properties
Density and phase 0.78 g/cm3, liquid
Solubility in water infinite
Other solvents virtually all
Melting point -55 °C (218 K)
Boiling point 120-122 °C (393-395 K)
Acidity (pKa) 8.97
Basicity (pKb) 5.85
Template:Chembox header | Structure
Coordination
geometry
sp3 throughout
Dipole moment 0 D
Template:Chembox header | Hazards
MSDS External MSDS
Main hazards flammable,
obnoxious odour
NFPA 704 Template:NFPA 704
Flash point 50 °F
R/S statement R: 11-20/22-34
S: 16-26-36/37/39-45
RTECS number KV7175000
Template:Chembox header | Supplementary data page
Structure and
properties
n = 1.4179
Thermodynamic
data
Phase behaviour
Solid, liquid, gas
Spectral data UV, IR, NMR, MS
Template:Chembox header | Related compounds
Related amines ethylene diamine,
PMDTA,
trimethyltriazacyclononane
Template:Chembox header | Except where noted otherwise, data are given for
materials in their standard state (at 25°C, 100 kPa)
Infobox disclaimer and references

Tetramethylethylenediamine, commonly known as TMEDA (or TEMED) is the chemical compound with the formula (CH3)2NCH2CH2N(CH3)2. This species is derived from ethylene diamine by replacement of the four N-H groups with four N-methyl groups. It has a disagreeable fishy odour.

As a reagent in organic and inorganic synthesis

TMEDA is widely employed as a ligand for metal ions. It forms stable complexes with many metal halides, e.g. zinc chloride, copper(I) iodide, giving complexes that are soluble in organic solvents. In such complexes, the TMEDA serves as a bidentate ligand.

Perhaps TMEDA is most renowned for its affinity for lithium ions. It converts butyl lithium into a cluster of higher reactivity than the hexamer. BuLi/TMEDA is able to metallate or even doubly metalate many substrates including benzene, furan, thiophene, N-alkylpyrroles, and ferrocene.[1] Many anionic organometallic complexes have been isolated as their [Li(TMEDA)2]+ complexes.[2] In such complexes [Li(TMEDA)2]+ behaves like a quaternary ammonium salt, such as [NEt4]+, except that it is more resistant to deprotonation.

Other uses

Tetramethylethylenediamine is used with ammonium persulfate to catalyze the polymerization of acrylamide in making a polyacrylamide gel, used in gel electrophoresis and Western blotting. Although the amounts used in this technique may vary from method to method, 0.1-0.2% v/v TMEDA is a "traditional" range.

References

  1. Haynes, R. K.; Vonwiller, S. C. "N,N,N',N'-Tetramethylethylenediamine" in Encyclopedia of Reagents for Organic Synthesis (Ed: L. Paquette) 2004, J. Wiley & Sons, New York. doi: 10.1002/047084289.
  2. Morse, P. M.; Girolami, G. S. "Are d0 ML6 Complexes Always Octahedral? The X-ray Structure of Trigonal Prismatic [Li(tmed)]2[ZrMe6]," Journal of the American Chemical Society 1989, volume 111, 4114-5.doi:10.1021/ja00193a061

External links

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