Internal Seminar: Sebastien Lapointe, PhD Student, Coordination and Chemistry Catalysis Unit

Internal Seminar

Speaker: Sebastien Lapointe, PhD student, Coordination Chemistry and Catalysis Unit (Julia Khusnutdinova Unit)

Title: Novel bulky PNP pincer ligands: the effect on the stabilization and geometry of unusual oxidation states of Ni complexes

Abstract:

PNP pincer ligands (PNP = 2,6-bis[(dialkylphosphino)methyl]pyridine) have been extensively studied in catalysis and in small molecule activation due to their ability to stabilize reactive species, or to induce new modes of reactivity that lead to new catalytic reactions with their associated metal complexes. They often feature Metal-Ligand Cooperation (MLC) via participation of the CH2 arm in protonation/deprotonation.(1) While sometimes such reactivity can be instrumental in catalysis, in other cases it can lead to undesired irreversible ligand modification or decomposition.(2)

In this light, we designed two novel bulky, electron-rich PNP pincer ligands and their complexes with Ni in oxidation states +2 and +1. While nickel(II) complexes exhibit expected square planar geometry for both ligands studied in this work, nickel(I) complexes show different geometry at the metal center depending on the degree of steric hindrance at the ligand. These unusual Ni(I) complexes showed remarkable stability likely due to the presence of bulky ligands and were studied by X-ray crystallography, ESR spectroscopy and the Evans method. The reactivity of Ni +complexes was tested with small molecules.

Please join us for free pizza, soft drinks, and scientific discssion following the Internal Seminar from 5:00-5:30pm. Please kindly bring your own plate and mug.