To use all functions of this page, please activate cookies in your browser.
With an accout for my.chemeurope.com you can always see everything at a glance – and you can configure your own website and individual newsletter.
- My watch list
- My saved searches
- My saved topics
- My newsletter
Lithium triethylborohydride (LiEt3BH), commonly abbreviated to LiTEBH or Superhydride, is a powerful and selective reducing agent used in inorganic and organic chemistry. LiTEBH is far more powerful than lithium borohydride and more powerful than lithium aluminum hydride (LAH) in many cases. One of the main advantages of LiTEBH is that it is safer than LAH.
LiTEBH rapidly reduces:
Additional recommended knowledge
Compounds of lithium hydride and sodium hydride with trialkylboranes such as LiTEBH were first discovered in the course of War Research in the period of 1942-45 at the University of Chicago by Professor H.C. Brown and Professor H.I. Schlesinger.
LiTEBH is most commonly produced by the reaction between lithium hydride (LiH) and triethylborane (Et3B) in tetrahydrofuran (THF)
which gives a very high yield of approximately 99%. The subsequent solution is collected by filtration of any excess LiH to give a crystal clear solution. LiTEBH in THF has appeared to be stable indefinitely under an inert atmosphere.
Structure and Chemical Properties
The structure of LiTEBH causes the compound to be a very strong hydride source. Hydrogen is more electronegative than boron which causes the B-H bond to be strongly polarized with boron having a partial positive charge and hydrogen having a partial negative charge. The ethyl groups on the boron also aids to this abnormal polarizability by removing additional electron density from the boron making it even more electropositive. This polarization of the B-Et and B-H bonds causes the hydrogen to be in the (-I) oxidation state instead of its usual (+I) oxidation state which leads to its high reactivity with atoms that can accept electrons to allow the hydrogen to go to its (+I) oxidation state.
Aldehydes and ketones rapidly utilizes 1 equivalent of LiTEBH to form the alcohol shown respectively in (1) and (2).
LiTEBH reacts violently and exothermically with water, alcohols, or acids releasing flammable hydrogen gas which can ignite explosively and the pyrophoric triethylborane vapor can ignite spontaneously. It can cause severe eye, skin, and respiratory tract burns.
Categories: Lithium compounds | Borohydrides | Reducing agents
|This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article "Lithium_triethylborohydride". A list of authors is available in Wikipedia.|