Synthesis, Structure and Reactivity of Pincer Supported Nickel Carbenes and Related Complexes
Date
2018-11-13
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Abstract
The activation of abundant or renewable feedstocks such as H2O, O2, CH4, CO2, N2 and NH3 and the development of sustainable systems for their productive conversion to value-added products are necessary to meet the growing demand for chemical and energy products. Complicating this are the unique challenges presented by these substrates and the current reliance on expensive and sparse 2nd and 3rd row transition metals to effect these bond activations. This work centres on the further development of nickel carbene complexes as a platform for small molecule activation. These species had been previously demonstrated to heterolytically activate numerous acidic bonds, including the weakly acidic bonds of ammonia. The landscape of bond activations has been expanded beyond acidic substrates to include hydridic, industrially important silanes, coupled with detailed mechanistic studies. Insights gleaned through these studies allowed for rational ligand modifications to improve stability, facilitating the study of CO2 and CO activation, and the synthesis of an umpolung cationic nickel carbene. The polarity reversal of the Ni-C moiety resulted in reactivity distinct from its neutral analogue, as exemplified by the unique ligand centred activation of ammonia. Further, preliminary studies suggest these reverse-polarity carbenes may be competent in catalytic hydrodefluorination of alkyl fluorides, an important first step in moving Ni carbenes from academic curiosity to application. Preliminary work on the synthesis of isostructural Pt carbenes will also be presented, allowing for a comparison of the bonding and reactivity in group 10 carbenes.
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Keywords
Organometallic, Nickel, PCP, Carbene, Small Molecule Activation
Citation
LaPierre, E. A. (2018). Synthesis, Structure and Reactivity of Pincer Supported Nickel Carbenes and Related Complexes (Doctoral thesis, University of Calgary, Calgary, Canada). Retrieved from https://prism.ucalgary.ca. doi:10.11575/PRISM/34229