Tetramethylethylenediamine

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Tetramethylethylenediamine
Skeletal formula of tetramethylethylenediamine with some implicit hydrogens shown
Ball and stick model of tetramethylethylenediamine
Identifiers
Abbreviations TMEDA, TEMED
CAS number 110-18-9 YesY
PubChem 8037
ChemSpider 7746 N
EC number 203-744-6
UN number 2372
MeSH N,N,N',N'-tetramethylethylenediamine
ChEBI CHEBI:32850 N
RTECS number KV7175000
Beilstein Reference 1732991
Gmelin Reference 2707
Jmol-3D images Image 1
Properties
Molecular formula C6H16N2
Molar mass 116.20 g mol−1
Appearance Colorless liquid
Odor Ichtyal, ammoniacal
Density 0.7765 g mL−1 (at 20 °C)
Melting point −58.6 °C; −73.6 °F; 214.5 K
Boiling point 121.1 °C; 249.9 °F; 394.2 K
Solubility in water Miscible
Acidity (pKa) 8.97
Basicity (pKb) 5.85
Refractive index (nD) 1.4179
Structure
Hybridisation sp3 at C2, N5, C6, C10, C13, N16, C17, C21
Dipole moment 0 D
Hazards
MSDS External MSDS
GHS pictograms The flame pictogram in the Globally Harmonized System of Classification and Labelling of Chemicals (GHS) The corrosion pictogram in the Globally Harmonized System of Classification and Labelling of Chemicals (GHS) The exclamation-mark pictogram in the Globally Harmonized System of Classification and Labelling of Chemicals (GHS)
GHS signal word DANGER
GHS hazard statements H225, H302, H314, H332
GHS precautionary statements P210, P280, P305+351+338, P310
EU Index 612-103-00-3
EU classification Highly Flammable F Corrosive C
R-phrases R11, R20/22, R34
S-phrases (S1/2), S16, S26, S36/37/39, S45
NFPA 704
Flammability code 4: Will rapidly or completely vaporize at normal atmospheric pressure and temperature, or is readily dispersed in air and will burn readily. Flash point below 23 °C (73 °F). E.g., propane Health code 2: Intense or continued but not chronic exposure could cause temporary incapacitation or possible residual injury. E.g., chloroform Reactivity code 1: Normally stable, but can become unstable at elevated temperatures and pressures. E.g., calcium Special hazards (white): no codeNFPA 704 four-colored diamond
Flash point 20 °C (68 °F; 293 K)
Explosive limits 0.98–9.08%
LD50
  • 5.39 g kg−1 (dermal, rabbit)
  • 268 mg kg−1 (oral, rat)
[2]
Related compounds
Related amines Triethylenetetramine
Related compounds
Supplementary data page
Structure and
properties
n, εr, etc.
Thermodynamic
data
Phase behaviour
Solid, liquid, gas
Spectral data UV, IR, NMR, MS
Except where noted otherwise, data are given for materials in their standard state (at 25 °C (77 °F), 100 kPa)
 N (verify) (what is: YesY/N?)
Infobox references

Tetramethylethylenediamine (TMEDA or TEMED) is a chemical compound with the formula (CH3)2NCH2CH2N(CH3)2. This species is derived from ethylenediamine by replacement of the four N-H groups with four N-methyl groups. It is a colourless liquid, although old samples often appear yellow. Its odor is remarkably similar to that of rotting fish.[3]

As a reagent in organic and inorganic synthesis[edit]

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

TMEDA has an affinity for lithium ions.[3] It converts n-butyllithium into a cluster of higher reactivity than the hexamer. BuLi/TMEDA is able to metallate or even doubly metallate many substrates including benzene, furan, thiophene, N-alkylpyrroles, and ferrocene.[3] Many anionic organometallic complexes have been isolated as their [Li(tmeda)2]+ complexes.[4] In such complexes [Li(tmeda)2]+ behaves like a quaternary ammonium salt, such as [NEt4]+.

TMEDA adduct of lithium bis(trimethylsilyl)amide. Notice that the diamine is a bidentate ligand.[5]

Other uses[edit]

TMEDA is used with ammonium persulfate to catalyze the polymerization of acrylamide when making polyacrylamide gels, used in gel electrophoresis, for the separation of proteins or nucleic acids. Although the amounts used in this technique may vary from method to method, 0.1-0.2% v/v TMEDA is a "traditional" range. TMEDA can also be a component of Hypergolic propellants.

References[edit]

  1. ^ "N,N,N',N'-tetramethylethylenediamine - Compound Summary". PubChem Compound. USA: National Center for Biotechnology Information. 16 September 2004. Retrieved 30 June 2012. 
  2. ^ "MSDS" (pdf). 
  3. ^ a b c Haynes, R. K.; Vonwiller, S. C.; Luderer, M. R. (2006). "N,N,N',N'-Tetramethylethylenediamine". In Paquette, L. Encyclopedia of Reagents for Organic Synthesis. New York: J. Wiley & Sons. doi:10.1002/047084289X.rt064.pub2. 
  4. ^ Morse, P. M.; Girolami, G. S. (1989). "Are d0 ML6 Complexes Always Octahedral? The X-ray Structure of Trigonal Prismatic [Li(tmed)]2[ZrMe6]". Journal of the American Chemical Society 111 (11): 4114–4116. doi:10.1021/ja00193a061. 
  5. ^ K. W. Henderson, A. E. Dorigo, Qi-Long Liu, P. G. Williard "Effect of Polydentate Donor Molecules on Lithium Hexamethyldisilazide Aggregation:  An X-ray Crystallographic and a Combination Semiempirical PM3/Single Point ab Initio Theoretical Study" J. Am. Chem. Soc. 1997, volume 119, pp. 11855. doi:10.1021/ja971920t