Steric repulsion is important to understand the bond formation process in molecules and your substituents might play a bigger role than you’d expect, an Amsterdam group reports in Chemical Science.

There are very little chemical bonds more thoroughly researched than the carbon-carbon (C-C) bond. That’s why it should come as no surprise that some binding concepts are intuitively understood. Take for example the size effect of substituents on the C-C bond. The bigger the substituents, the less stable the bond is. But to a certain extent, the reverse effect is true for Si-Si bonds: bigger substituents result in a stronger bond between the silicon atoms. Why is that? This question has been explored by Daniela Rodrigues Silva, Eva Blokker, Matthias Bickelhaupt and colleagues from the Free University Amsterdam in a collaboration with Nouryon.