[Goala]

Hey Guys,

I was on SDBS, and was looking at the IR for Tetracyclone.

Why is there an absorption in the 3400 range if there is no O-H in the molecule?!

http://riodb01.ibase.aist.go.jp/sdbs/cgi-bin/IMG.cgi?imgdir=ir&fname=NIDA18818&sdbsno=13741

[opsomath]

It doesn't, according to my search. You do mean tetraphenyl cyclopentadienone, right?

[Goala]

It doesn't, according to my search. You do mean tetraphenyl cyclopentadienone, right?

Yes, I do mean tetraphenyl cyclopentadienone. When I go to SDBS I look for tetraphenyl cyclopentadienone and click on IR spectra in KBr disk I get an absorption in the 3400 range. I have attached a picture of the spectra I got on SDBS.

[opsomath]

That's the KBr spectrum. Look at the Nujol one.

[Goala]

Ok cool, but why does the KBr one do that and the nujol doesn't?!

[discodermolide]

Ok cool, but why does the KBr one do that and the nujol doesn't?!

Is your KBr wet?

[Goala]

Is your KBr wet?

Well I got this from a database, SDBS to be exact.

So I am guessing, the people who prepared this IR spectra didn't do a good job because they exposed the KBr to moisture and the KBr picked up water and it showed in the broad absorption in the 3400 cm-1 range?

[Cryolite]

The ketone could have a very stable hydrate form. Check if you can draw a mechanism for its stabilization, and use it to explain its presence.

[opsomath]

The ketone could have a very stable hydrate form.

Hmm. Is that so? Usually having no substituents (aldehydes or formaldehyde) or electron-withdrawing ones alpha to the carbonyl favor the hydrate, like in the case of formaldehyde, ninhydrin, or chloral hydrate.