Molecular toy building blocks

    I would like to introduce some geometrically interesting compounds this week. I think they are interesting because they have all kinds of structure—whatever you can imagine. They are just like tiny toy building blocks in microscopic world.

    The compounds that I want to talk about is “Platonic hydrocarbon”(柏拉圖烴). There are five Platonic solids: tetrahedron (正四面體), cube(正六面體), octahedron (正八面體), dodecahedron (正十二面體), icosahedron (正二十面體). But acutally only tetrahedron, cube, and icosahedron have their counterparts in hydrocarbon (due to the nature of carbon in bonding¹), and they are tetrahedrane, cubane, and dodecahedrane respectly.²

tetrahedrane, cubane, and dodecahedrane

   

  

    Of course there are piles of derivatives (衍生物) of Platonic hydrocarbon.For example:

Octanitrocubane, which is very explosive thus can be used in bomb and fuel:

Pagodane, an isomer of dodecahedrane:

  

Prismane, an isomer of bezene:

Fullerene (C60), which we are more familiar with:

However, chemist synthesis these compounds not only for fun but to collect data of these molecules. Chemistry behind these odd molecules is different form that behind ordinary molecules since they usually suffered from huge angle strain and are quite unstable. The data help chemist to develop and improve the existing theories (such as theoretical chemistry, computational chemistry, molecular modeling… and so on) and move further in chemistry.  

What’s more, molecule structure has no boundary so there are more left for us to explore!

1.The nature of carbon in bonding is that it merely has four valence and the angle shouldn't deviated from 109.5 degree too much.

2.Actually, tetrahedrane has not been synthesized yet, but lots of its derivatives have been published and the theoretical calculation also supports its stablity.

Reference:

1.https://en.wikipedia.org/wiki/Platonic_hydrocarbon

2.http://sites.northwestern.edu/scheidt/files/2011/11/012004_Galliford_Pltsolids.pdf

3.https://www.scripps.edu/baran/images/grpmtgpdf/Shenvi_Jan_06.pdf