Novel, inexpensive catalysts enabling noble metal chemistry

Alkynes have many uses in industry. Until now, it was assumed that gold- or platinum-based catalysts were absolutely necessary for certain chemical reactions with alkynes. Chemists at Martin Luther University Halle-Wittenberg (MLU) have now succeeded in carrying out the same reactions with considerably less expensive materials. The team reports on its work in the Journal of the American Chemical Society.

Alkynes are hydrocarbons that contain carbon-carbon triple bonds. They are among the basic building blocks of organic chemistry. "For the desired industrial reactions, the triple bond must be activated in a special, so-called soft, manner. So far, this has been observed primarily in reactions with catalysts based on precious metals, especially gold or platinum. There is a long-standing consensus in the scientific community on why these elements dominate in the intricate types of alkynes' activation," explains Professor Konstantin Amsharov from the Institute for Chemistry at MLU. However, gold and platinum are not only expensive but also relatively rare. 

In the new study, the chemists show that under certain conditions, a catalyst based on aluminum oxide induces activation of alkynes similarly to gold- and platinum-based catalysts. "This material is inexpensive and accessible," says Amsharov. The team also provides an explanation for this. "With our new approach, we can mimic the interaction of gold and alkyne species at the electron level. In some cases, the reactions were even more efficient," says Amsharov. 

So far, the researchers have proven the new method only on a laboratory scale. "With our study, we have provided fundamental proof that metal oxides can be used as comparable catalysts," says Dr. Vladimir Akhmetov from MLU, co-author of the paper. Further studies will now investigate which common reactions the discovery could be applied to.