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Windowpane Redux (Pretty pictures)

By moleculeoftheday on October 19, 2006.

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.

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

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

Here is 5.5.5.6 windowpane:

[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

[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

And here is an unstrained compound, tetramethylmethane (2,2-dimethylpropane):

Tetramethylmethane: InChI=1/C5H12/c1-5(2,3)4/h1-4H3

Tetramethylmethane: InChI=1/C5H12/c1-5(2,3)4/h1-4H3

The changes are subtle but result in enormous energy changes. The molecules go in increasing order of stability (Decreasing energy). This is one of the things it's a little weird to start thinking about in chemistry. Molecules are rarely completely rigid; they're usually at least a little floppy, and the way we draw them isn't usually quite the right shape.

See you tomorrow.

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Topologically/Geometrically Interesting

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http://ww.mazepath.com/uncleal/fenestr.png
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