There are almost an endless number of theoretical molecular possibilities in the world of chemistry. Some chemicals are simple, while some are complex. In addition, there are some that are sought because they are anticipated to be of practical use to mankind. Others, may be mere curios – toys of the intellect. Yes, even adults must have their toys! And so, this series, the Chemistry Curio Series. I hope the chemicals I will highlight in this series may both entertain and inform you.
“We do the difficult immediately, but the impossible may take a little time.” Investigating chemists enjoy challenges. One such challenge was to prepare cubane. Cubane had no anticipated special properties or practical application.
Cubane has the molecular formula C8H8. It is actually a cube drawn with a carbon at each corner. Sticking out of each corner is one hydrogen (See the image associated with this article). The answer is that carbon likes to form angles between atoms of 109.5 degrees, whereas, the angles in cubane are only 90 degrees. They are all right angles. This means that the atoms are strained nearly 20 degrees out of their desired configuration. To do that requires energy. Increase energy where it is not normal, and you decrease stability. In addition, such a molecule doesn’t “want” to form in the first place.
Cubane Finally Synthesized
For that reason, it wasn’t until 1964 that cubane was finally successfully synthesized. The chemistry, to the uninitiated, looks tough. What is even tougher than understanding the chemistry once it has been accomplished is to foresee what might work in the first place! Would you like to know how to make cubane? The “Imperial College of London” should enlighten you. Once cubane was prepared, its properties became of great interest. The question naturally arose, Would cubane be useful for anything?
Cubane’s Properties – Explosive Possibilities?
Generally, a hydrocarbon with only eight carbons would suggest a liquid. Cubane is a solid – a waxy, rhombohedral, crystalline solid. Cubane also is quite stable, despite the bond strain. This may be because of its high level of symmetry.
Cubane has an exceptional density, and although being stable, it is also very reactive. For this reason, there should be cubane derivatives that would make very powerful explosives. Thus, it is theorized that octa-nitrocubane will make a very powerful explosive, once large enough quantities can be synthesized.
It is believed cubane derivatives may be useful in applications involving cancerous tumors, HIV, and AIDS.
Cubane Polymer Optical Displays?
Optically transparent, yet rigid cubane polymers may be well suited for liquid crystal design, hence optical displays.
Imperial College of London.
Combustion, Explosion, and Shock Waves – On the detonation parameters of octa-nitrocubane.