Cyclic (alkyl)(amino)carbenes with a 1,1'-ferrocenediyl backbone

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Cyclic (alkyl)(amino)carbenes (CAACs) exhibit a significantly more pronounced ambiphilicity than classic “Arduengo type” N-heterocyclic carbenes (NHCs) and are thus able to activate fundamentally important small molecules such as, for example, CO and NH3 already under mild conditions. N-heterocyclic carbenes with a 1,1’-ferrocenediyl backbone (fcNHCs) are similar in this respect to CAACs, since their pronounced ambiphilicity, and hence high reactivity, is quite unusual for NHCs. In this project, both types of particularly ambiphilic carbenes, viz. CAACs and fcNHCs, will be combined. The project aims at gaining access to cyclic (alkyl)(amino)carbenes with a 1,1’ferrocendiyl backbone (fcCAACs) and studying them in terms of their steric and electronic properties as well as their reactivity. Differences with respect to established CAACs will be of particular interest. According to our hypothesis, fcCAACs will exhibit a particularly pronounced ambiphilicity, and hence particularly high reactivity. Consequently, we will specifically study their capability for small-molecule activation – a task where fcCAACs are expected to be superior to established CAACs. Furthermore, we surmise that the ability for stabilizing (metallo-)radicals, which is typical for CAACs, may be strengthened markedly by the presence of the redox-active 1,1’-ferrocenediyl backbone, giving access to novel stable oligoradicals.