N,N’-Dimethyimidazolium-2-Carboxylate as a Ligand Precursor for the Accession of a Constrained Olefin Dimerization Catalyst

A significant market share of modern plastics is held by long-chain hydrocarbon polymers, such as polyethylene and polypropylene, properties of which can be dramatically changed by addition of linear α-olefins. Production of linear α-olefins involves the creation of many unwanted byproducts, representing significant quantities of both economic and ecological waste. While catalysts have been designed to selectively produce industrially useful olefins, these catalysts often encounter challenges such as synthesis of other unwanted byproducts, slow reaction times, and difficulty of synthesis. Based on one such prior catalyst, we report here synthetic work towards a cobalt catalyst with a constrained N-heterocyclic carbene supporting ligand predicted to allow for more favorable product distributions. Synthesis of two precursors to a sterically unhindered N-heterocyclic carbene, as well as development of a synthetic protocol for the coordination of N,N’- dimethylimidazolium-2-carboxylate to Cp*Co(ethene)2 was completed. Activation of the precatalyst and preliminary catalytic experiments were performed, though abbreviated research periods made complete analysis impossible. Finally, we report evidence of the formation of a novel cobalt-NHC dimer as a temperature controlled byproduct of the desired catalyst synthesis.