Many basic chemical processes require the cleavage, or activation, of strong covalent bonds in ubiquitous and inexpensive small molecules such hydrogen, nitrogen, ammonia, water and carbon dioxide. In nature, small molecule activation is done with the help of enzymes and a great deal of research efforts has been directed to achieve the same with manmade catalysts. An illustrative example is the Haber-Bosch process, which, like its biological counterpart nitrogen fixation, produces ammonia from N2 with the help of a catalyst. This process is vital for our society as the vast majority of the ammonia produced is consumed by the fertilizer industry, without which the world would face an imminent food crisis. Besides the Haber-Bosch process, there are many more chemical reactions performed at the industry level which involve the activation of small molecules and which would be impossible to perform without efficient catalysts.
This research project focussed on the interesting possibility to perform small molecule activation with main-group compounds that, in contrast to many transition metal catalysts, consist entirely of cheap earth-abundant elements. The overall objective of the project was to find new ways to achieve small molecule activation using main-group compounds that typically do not display such reactivity. Of key interest were main-group diradicaloids, compounds with metal-metal bonds and metalloid clusters, frustrated Lewis pairs as well as electron precise boron compounds. The planned initiatives were primarily of fundamental scientific importance but also of potential practical value as many main-group systems, such as frustrated Lewis pairs, are currently being examined as novel metal-free catalysts. The project resulted in the synthesis and characterization of several new main-group systems for small molecule activation and uncovered the mechanisms by which these interesting and novel species function.
