Windowpane (Another cutesy-name strained ring system)

Like cubane, windowpane (also named "[4.4.4.4]fenestrane" for the Latin for window) is another of those compounds people like because it looks like something anthropomorphic, with clean right angles (in contrast to the bulk of molecules, which assume their bond angles with little regard for what looks nice on paper). This introduces a great deal of strain, since quantum mechanics would rather we avoid bond angles very far from ~110 degrees in these sorts of compounds. See this entry on cubane from the old site for more information on why right and 180 degree angles are so tricky here.

In fact, planar carbon is so hard to come by, we've had much more luck talking about it than making it. I'm not sure what we've managed to make and what we haven't.

Windowpane: InChI=1/C9H12/c1-5-2-7-4-8-3-6(1)9(5,7)8/h5-8H,1-4H2

I think (and someone who knows, tell me if I'm wrong) the closest we've got are the higher fenestranes (like 5.5.5.6), which are a little less unhappy existing, and "broken" 4.4.4.4 fenestrane (yes, they call it "broken windowpane.").

Broken Windowpane: InChI=1/C8H12/c1-3-8-4-2-7(8)5-6(1)8/h6-7H,1-5H2

[5.5.5.6]fenestrane: InChI=1/C14H22/c1-2-10-4-6-12-8-9-13-7-5-11(3-1)14(10,12)13/h10-13H,1-9H2

More like this

For a better idea of how the bond angles look, here is an energy-minimized structure of windowpane (4.4.4.4). Notice how it's (nearly) planar. That central carbon atom (middle gray dot, blues are hydrogens) is the one to watch. Here is 5.5.5.6 windowpane: And here is an unstrained compound,…
I know a lot of people don't have access to these journals, so I try and avoid links to walled content, but there's a review article on fenestranes and planar carbon in Chemical Reviews some might enjoy. Check out "Carbon Flatland: Planar Tetracoordinate Carbon and Fenestranes." Check out the…
The following blather is the first part in a continuing series of essays addressing the inherent pragmatism of modern physics. Let's call this a "Primer" on String Theory. So, string theory is in trouble. For those readers who haven't watched the excellent NOVA special "The Elegant Universe" in the…
Professor Hubert Farnsworth: I'm sorry, Fry, but astronomers renamed Uranus in 2620 to end that stupid joke once and for all. Fry: Oh. What's it called now? Professor Hubert Farnsworth: Urrectum. Here, let me locate it for you. Fry: No, no, I, I think I'll just smell around a bit over here. Too bad…