Tandem catalysis is defined as coupled catalyses in which the sequential transformations of the substrate occur via two (or more) mechanistically distinct catalytic cycles. It can be commonly executed with two different methods; a single catalyst (heterobimetallic complex) performing different reactions of the whole process or two/more catalysts are utilized for the same purpose.1 Real Money Rummyers are focused towards the development of more effective tandem catalyst systems as its applications in synthetic chemistry greatly reduce the amount of waste, cost, energy consumption, and time.2 The recent studies show that synergistic/cooperative effect between the metal centers of heterobimetallic complexes results in outstanding activity in tandem catalytic reactions3 and thus inspire other researchers toward the advancement of heterobimetallic complexes. However, there are hurdles to be crossed for the synthesis of heterobimetallic complexes as it requires a ligand with two different binding sites and meticulous selection of metals so that the stability of the complex can be assured under the reaction conditions used during sequential metalation.3 Recent reports show that the approach of using imidazole/triazole based poly N-heterocyclic carbenes (NHCs) containing ligands are really successful for accessing the heterobimetallic complexes.3 NHCs are superior over traditional ligands mainly due to their better σ-donor nature and flexibility in stereoelectronic modifications.4 They form stable metal complexes with various transition metals in almost all oxidation states. These properties of NHC based ligands made them the appropriate candidates for the preparation of heterobimetallic complexes. Starting with the examples from various co-catalytic/bimetallic systems existing in nature, the presentation will highlight the evolution of NHC based ditopic ligand systems and the corresponding heterobimetallic complexes along with their tandem catalytic applications. The research objectives and primary outcomes will also be presented during the seminar.

References:
1. Zanardi, A.; Mata, J. A.; Peris, E. J. Am. Chem. Soc. 2009, 131, 14531.
2. Pezük, L. G.; Şen, B.; Hahn, F. E.; Türkmen, H. Organometallics 2019, 38, 593.
3. Mata, J. A.; Hahn, F. E.; Peris, E. Chem. Sci. 2014, 5, 1723.
4. Hahn, F. E. Angew. Chem. Int. Ed. 2006, 45, 1348.