Chemistry Special Seminar - Johanna Blacquiere, Western University

Title

Harnessing Ligand Dynamics for Sustainable Catalysis

Abstract

Factors that promote sustainable catalysis include catalysts that can be used at very low catalyst loadings, and those that promote enabling transformations with minimal waste generation. These goals can be achieved with privileged catalyst and ligand structures. We have pursued the development of catalysts with cooperative ligands that can assist catalytic turnover through reversible changes, such as proton shuttling,^[1] and changes to ligand coordination mode.^[2] Both of these ligand types will be covered in this seminar. First, we have demonstrated that [Ru(Cp)(P^R₂N^R’₂)(MeCN)]PF₆ catalysts (1) are active catalysts for alkyne functionalization, which depends on proton shuttling by the pendant tertiary amine groups of the P^R₂N^R’₂ ligand.^[3] Mechanistic insight has guided catalyst redesign strategies, as well as redeployment toward intermolecular C-O bond formation. The second portion of the presentation will cover phosphine 1-azaallyl (P^AzA) complexes, which we designed to exploit dynamic changes in coordination mode. The P^AzA ligand effectively stabilizes an operationally-unsaturated ruthenium complex (2).^[4] The reactivity of 2 and related complexes will be discussed.

[1]           E. S. Wiedner, A. M. Appel, S. Raugei, W. J. Shaw, R. M. Bullock, Chem. Rev. 2022, 122, 12427-12474.

[2]           J. M. Blacquiere, ACS Catal. 2021, 11, 5416-5437.

[3]           D. E. Chapple, M. A. Hoffer, P. D. Boyle, J. M. Blacquiere, Organometallics 2022, 41, 1532-1542.

[4]           M. B. Kindervater, V. N. Staroverov, K. M. K. Jackman, A. A. Fogh, L. S. G. Kelley, L. Lim, S. A. Sirohey, P. D. Boyle, J. M. Blacquiere, Dalton Trans. 2023, 52, 10744-10750.

Date:    Friday, April 12

Time:    1:30 pm

Place:    Thorvaldson 159