Tetramethylethylenediamine

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Tetramethylethylenediamine
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Names
Preferred IUPAC name
N,N,N′,N′-Tetramethylethane-1,2-diamine[1]
Identifiers
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3D model (JSmol)
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Abbreviations TMEDA, TEMED
1732991
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2707
MeSH N,N,N',N'-tetramethylethylenediamine
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UN number 2372
  • InChI=1S/C6H16N2/c1-7(2)5-6-8(3)4/h5-6H2,1-4H3 ☒N
    Key: KWYHDKDOAIKMQN-UHFFFAOYSA-N ☒N
  • CN(C)CCN(C)C
Properties
C6H16N2
Molar mass 116.208 g·mol−1
Appearance Colorless liquid
Odor Fishy, 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
Miscible
Acidity (pKa) 8.97
Basicity (pKb) 5.85
1.4179 (20 °C)[2]
Hazards
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2
4
1
Flash point 20 °C (68 °F; 293 K)
Explosive limits 0.98–9.08%
Lethal dose or concentration (LD, LC):
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  • 5.39 g kg−1 (dermal, rabbit)
  • 268 mg kg−1 (oral, rat)
[3]
Related compounds
Related amines
 Triethylenetetramine
Related compounds
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Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).

Template:Chembox Footer/trackingTemplate:Short description

Tetramethylethylenediamine (TMEDA or TEMED, sometimes TMEN) is a chemical compound with the formula (CH3)2NCH2CH2N(CH3)2. This species is derived from ethylenediamine by replacement of the four amine hydrogens with four methyl groups. It is a colorless liquid, although old samples often appear yellow. Its odor is similar to that of rotting fish.[4]

As a reagent in synthesis

File:LiHMDS-tmeda complex.png
Structure of the TMEDA adduct of LiN(Si(CH3)3)2.[5] Color code: blue = N, lavender = Li, yellow = Si

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.[4] When mixed with n-butyllithium, TMEDA's nitrogen atoms coordinate to the lithium, forming a cluster of higher reactivity than the tetramer or hexamer that n-butyllithium normally adopts. BuLi/TMEDA is able to metallate or even doubly metallate many substrates including benzene, furan, thiophene, N-alkylpyrroles, and ferrocene.[4] Many anionic organometallic complexes have been isolated as their [Li(tmeda)2]+ complexes.[6] In such complexes [Li(tmeda)2]+ behaves like a quaternary ammonium salt, such as [NEt4]+.

sec-Butyllithium/TMEDA is a useful combination in organic synthesis where the n-butyl analogue adds to substrate. TMEDA is still capable of forming a metal complex with Li in this case as mentioned above.

In molecular biology

TEMED is a common reagent in molecular biology laboratories, as a polymerizing agent for polyacrylamide gels in the protein analysis technique SDS-PAGE.[7]

Other uses

The complexes (TMEDA)Ni(CH3)2 and [(TMEDA)Ni(o-tolyl)Cl] illustrate the use of tmeda to stabilize homogeneous catalysts.[8][9]

File:Doyle catalyst.tif
Synthesis of [(TMEDA)Ni(o-tolyl)Cl]

References

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  1. ^ Page Module:Citation/CS1/styles.css has no content."N,N,N′,N′-tetramethylethylenediamine – Compound Summary". PubChem Compound. USA: National Center for Biotechnology Information. 16 September 2004. Retrieved 30 June 2012.
  2. ^ Page Module:Citation/CS1/styles.css has no content.Lide, David R., ed. (2009). CRC Handbook of Chemistry and Physics (90th ed.). Boca Raton, Florida: CRC Press. ISBN 978-1-4200-9084-0.
  3. ^ Page Module:Citation/CS1/styles.css has no content."MSDS" (PDF).[permanent dead link]
  4. ^ a b c Page Module:Citation/CS1/styles.css has no content.Haynes, R. K.; Vonwiller, S. C.; Luderer, M. R. (2006). "N,N,N′,N′-Tetramethylethylenediamine". In Paquette, L. (ed.). N,N,N′,N′-Tetramethylethylenediamine. Encyclopedia of Reagents for Organic Synthesis. New York: J. Wiley & Sons. doi:10.1002/047084289X.rt064.pub2. ISBN 0471936235.
  5. ^ Page Module:Citation/CS1/styles.css has no content.Henderson, K. W.; Dorigo, A. E.; Liu, Q.-L.; Williard, P. G. (1997). "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. 119 (49): 11855. Bibcode:1997JAChS.11911855H. doi:10.1021/ja971920t.
  6. ^ Page Module:Citation/CS1/styles.css has no content.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. Bibcode:1989JAChS.111.4114M. doi:10.1021/ja00193a061.
  7. ^ Page Module:Citation/CS1/styles.css has no content.Manns, Joanne M. (2011). "SDS-Polyacrylamide Gel Electrophoresis (SDS-PAGE) of Proteins". Current Protocols in Microbiology. 22. doi:10.1002/9780471729259.mca03ms22.
  8. ^ Page Module:Citation/CS1/styles.css has no content.Shields, Jason D.; Gray, Erin E.; Doyle, Abigail G. (2015-05-01). "A Modular, Air-Stable Nickel Precatalyst". Organic Letters. 17 (9): 2166–2169. doi:10.1021/acs.orglett.5b00766. PMC 4719147. PMID 25886092.
  9. ^ Page Module:Citation/CS1/styles.css has no content.Magano, Javier; Monfette, Sebastien (2015-04-17). "Development of an Air-Stable, Broadly Applicable Nickel Source for Nickel-Catalyzed Cross-Coupling". ACS Catalysis. 5 (5): 3120–3123. doi:10.1021/acscatal.5b00498.
  10. ^ Page Module:Citation/CS1/styles.css has no content.Jackson, W.Gregory; Rahman, A.F.M.Mokhlesur; Wong, M.Anthony (2004). "Solvent Exchange, Solvent Interchange, Aquation and Isomerisation Reactions of cis- and trans-[Co(tmen)2(NCMe)2]3+ in Water, Me2SO and MeCN: Kinetics and Stereochemistry". Inorganica Chimica Acta. 357 (3): 665–676. doi:10.1016/j.ica.2003.05.010.
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