Tetramethylethylenediamine

Tetramethylethylenediamine

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
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 (pK_a)	8.97
Basicity (pK_b)	5.85
Structure
Coordination geometry	sp³ throughout
Dipole moment	0 D
Hazards
MSDS	External MSDS
Main hazards	flammable, obnoxious odour
NFPA 704	4 2 1
Flash point	50 °F
R/S statement	R: 11-20/22-34 S: 16-26-36/37/39-45
RTECS number	KV7175000
Supplementary data page
Structure and properties	n = 1.4179
Thermodynamic data	Phase behaviour Solid, liquid, gas
Spectral data	UV, IR, NMR, MS
Related compounds
Related amines	ethylene diamine, PMDTA, trimethyltriazacyclononane
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.

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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

^ 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 10.1002/047084289.
^ 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

Categories: Amines | Chelating agents

This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article "Tetramethylethylenediamine". A list of authors is available in Wikipedia.