Talk:Lithium diisopropylamide
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"Organic Chemistry" 6th ed. (2004) by McMurry gives the pKa of LDA to be ~40 instead of ~34, does anyone else have any sources?
Diisopropylamine has a pKa of 35.7 (see The Chemist's Companion). McMurry probably rounded the value up-- not recommended when dealing with logarithms! :D
Lithium hexamethyldisilazide (LHMDS) is a weaker base than LDA, the acid form having a pKA of 26. Hope this helps!
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[edit] Oligomers
I have made pictures for the oligomer section, when I get the time I will add them to wikipedia.Cadmium
[edit] Please use formulas
Whoever is putting in the nice figures should put in a jargon-free captions with formulas - which molecules are being depicted? Not apparently [LiNiPr2]n, but some analogues or some sort of solvates. The article is about LiNiPr2 or oligomers of this formula, so at least one figure should show this stuff, not its THF adduct. --Smokefoot 01:28, 30 April 2006 (UTC)
Hi Smokefoot, I will add a picture of the polymeric LDA solid when I get around to it. I think that as LDA is used oftein in ether solvents that the dimer in THF diagram is more important than the picture of the polymer (LDA under much more rare conditions). I have rearranged the article to make it more clear, I have also added a section explaining why LDA is able to form different enolates to weaker or insoluble bases.Cadmium 21:40, 2 May 2006 (UTC)
A plain structure of LDA needs to be added, to make it clear exactly what the structure is. It needs to be clear not just through the name or a 3D picture of the dimer with THF adduct, so that someone can click on to the page and see the structure straight away (its what I was looking for). --Fizzyfifi 18:16, 6 June 2007 (UTC)
- Define "plain structure." Lots of chemicals have quite complex structures. Sorry for the unwelcome news.--Smokefoot 18:39, 6 June 2007 (UTC)
[edit] Mechanistic arrows
I could be wrong about this but I think the mechanistic arrows on the diagram in the oligomers section may be going in the wrong direction
Hello, yes, the arrows are going in the wrong direction - Can think of the N-Li bond ionically like at the top of the article. The -ve charge on N attacks the H atom, so, equivalently, the N-Li bonding electrons would attack the H atom. The mechanism shown at present is a hydride abstraction, not a deprotonation. MarkJMartz 11:50, 2 February 2007 (UTC) Edit MarkJMartz 13:32, 2 February 2007 (UTC)
[edit] Kinetic vs thermodynamic bases
I dunno if this section should be in this article. IMHO it could form the basis of a new article. Aaadddaaammm 22:26, 28 October 2006 (UTC)
[edit] Lithium diisopropylamide
HI EVERY ONE,
MY QUESTION IS WHY IT IS CALLED AS Lithium diisopropylamide NOT Lithium diisopropylamine? —Preceding unsigned comment added by 202.80.63.3 (talk) 07:43, 15 November 2007 (UTC)
- Good question, the amide page explains that the anions of amines (deprotonated) are called amides V8rik 17:02, 15 November 2007 (UTC)
I think we should consider revising the picture of LDA. To show it bonded to other molecules is missleading. How about just showing LDA by it self. —Preceding unsigned comment added by 194.130.163.67 (talk) 04:29, 4 December 2007 (UTC)
- excellent point, and maybe your recommended rendering should be presented. Amides (the anionic variety) are not ever free ions, but always strongly associated with cations, even though simplified presentations dont say as much. So we're in the familiar situation of telling the complicated "truth" or making the image very understandable.--Smokefoot 04:57, 4 December 2007 (UTC)
