Chemists Synthesize "Impossible" Molecule

neilest writes "Organic chemistry textbooks will need to be revised to recognize a chemical species that chemists have discovered at Northwestern University. The species -- pentamethylcyclopentadienyl cation -- was thought not to exist for long because theory said it was unstable. The full story can be found at this suntimes article"

ha!

[Nickovsky]

They didnt think it exist,
because no one could spell it!

pentamethblablahwhaaanly

So release it!

[MarkusQ]

"I've said this molecule is unstable and doesn't exist dozens of times in organic chemistry class, but as it turns out, the molecule had different ideas," Northwestern chemistry professor Joseph Lambert said.

Q: You've been calling something unstable for a while, but it turns out it was stable. What do you do?

A: Increment the version number and release it!

-- MarkusQ

What is it?

[Darkstorm]

The artical was short, and missing one major detail...What is it? If it was considered unstable, but now seems to be stable, wonderfull, but does it have an usefull purposes? I want the modified sugar molecule that has the proper atoms reversed so the body doesn't process it....Now that would be usefull. We could have all the sweet things we crave and never gain weight for it.

If they figure that one out that would be worth a nobel prize.

Re:What is it?

[MarkusQ]

The artical was short, and missing one major detail...What is it?

The said it was "a pentamethylcyclopentadienyl cation" which tells you exactly what they made if you have the right secret decoder ring [qmw.ac.uk].

penta- means five

-methyl- refers to a methane group; a methane group is a carbon with all it's free bonds capped with hydrogen.

pentamethyl- means it has five methyl- groups dangling off of it; they don't tell us where, but we'll shortly see why they didn't bother.

-cyclo- means the base structure is a ring.

-penta- is five again

-dienyl- means alternating single and double bonds like so ...--C==C--C==C--C==...

-cyclopentadienyl- means that it's a ring of five carbons with every other other bond double. But wait, you say, what does "every other mean" in a five element ring? Thus we get to...

-cation means it's got a positive charge, so the whole bonding picture may be off, with the double bonds playing resonance leap-frog around the ring.

So (in English) it's a positively charged ring of five carbon atoms, with a CH3 hanging off each carbon, and an average of 1.4 bonds between each pair of carbons in the ring.

As for what it's good for, that depends. It could be good for a thesis, or for tenure, or for funding, or...it all depends on where you are in the food chain.

-- MarkusQ

Re:What is it?

[bgins]

From the horse's mouth:

Our research is aimed at synthesizing new classes of molecules with useful and interesting electronic, optical, conformational, and spectroscopic properties. Many, but not all, of these molecules contain main-group elements such as silicon, germanium, sulfur, and phosphorus. We have recently prepared the first stable, three-coordinate silyl cations and the first stable cyclopentadienyl cation.

This sounds like it might conceivably be useful for a lot of things.

Explains the how a little better...

[jsimon12]

Here is an article that explains the how and why, which the article on Slashdot doesn't explai:

http://www.sciencedaily.com/releases/2002/04/02041 2074739.htm [sciencedaily.com]

Link to Lamberts Group

[jsimon12]

http://www.chem.northwestern.edu/~lambert/index.ht ml [northwestern.edu]