A study explains how chemical changes are produced by tension forces
So far, warmth, light and electricity have been the key tools to make chemical reactions; its result is the conversion of two molecules. However, some years ago it was seen that if some molecules were exposed to mechanical stress or tension forces they could also get chemical modifications, not seen under other conditions. The field that studies chemical relations on molecules and compounds with the mechanical force to which they are exposed is the covalent mechanochemistry, a thriving research field.
The study, now published in Nature Chemistry, shows an unexpected complexity in the reaction of disulphide reduction in alkaline solution, which avoids the covalent link break between atoms of carbon and sulphide when it is activated by an external mechanical force. In particular, disulphides in alkaline solution -molecules formed by the covalent link between two sulphur atoms-, show quite particular mechanochemical properties, since when they are exposed to a mechanical tension they undergo structural changes that completely modify their reactivity. The specific description of these changes was published by the authors in an article that appeared in Nature Chemistry in 2013.
“The results open the door to design specific applications for these small molecules, such as synthesis of materials that become more rigid when stressed (such as muscles and bones) or elastic bands that become shorter when pulled, or on the other hand, the application of ultrasounds to activate selective chemical reactions” says Jordi Ribas Ariño, researcher at the Faculty of Chemistry of the UB and member of the Reference Network in Theoretical and Computational Chemistry (XRQTC). Furthermore, these results allow predicting properties and behaviour of the mechanophores, molecules that can undergo a chemical reaction when exposed to external mechanical tension forces.
P. Dopieralski, J. Ribas-Ariño, P. Anjukandi, M. Krupicka, D. Marx. «Unexpected mechanochemical complexity in the mechanistic scenarios of disulfide bond reduction in alkaline solution». Nature Chemistry,octubre de 2016. Doi: 10.1038/nchem.2632