A ruthenium (II) N-heterocyclic carbene (NHC) complex was synthesized to investigate ligand dissociation as a possible deactivation pathway for the catalytic cycle for a transfer hydrogenation reaction. Diiodo(1,3-dimethylbenzimidazole-2-ylidene)(p-cymene)ruthenium(II) was synthesized for use as the catalytic species and was characterized using elemental analysis, NMR Spectrometry, electrospray mass spectrometry, UV-Visible spectroscopy, infrared spectroscopy, and single crystal X-ray diffraction. Using a proton NMR spectrometry, the catalytic hydrogen transfer from isopropanol to acetophenone was tracked. After one hour of reaction time, 94 % conversion of substrate to alcohol product was observed. The p-cymene complex was also observed, using proton NMR, to be 80% deactivated after one hour of reaction time. An ultraviolet-visible spectrum that is in excellent agreement with the experimental spectrum was computed using Gaussian calculations, which provides insight of the nature of the experimental absorptions.<br/>

Deactivation of a ruthenium(II) N-heterocyclic carbene p-cymene complex during transfer hydrogenation catalysis

256th National Meeting (2018)

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