Revealing the 3D Configuration of SOMC Catalysts

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Scientific Achievement
The three dimensional structure, orientation,  and configuration of a supported Ir catalyst was determined with atomic precision; the first such demonstration for a supported complex.

Significance and Impact
Catalytic activity and selectivity depend to a large degree on the structure of the active site, in particular the

3D config of SOMC catalyst
The 3D structure of the Ir pincer complex depicted on the Figure was determined through the measurement of a large number of 13C-surface distance measurements. The ligand orientation was optimized as illustrated with the heat maps on the right, which show the existence of a single well-defined configuration depicted in the background.

orientation of the ligands relative to the surface. Until now, these details were beyond the reach of all characterization tools.

Research Details

  • DNP-enhanced NMR spectroscopy is used to measure 13C-27Al distances between the ligands and the surface.
  • The 3D configuration is then optimized to maximize the agreement with experiment.
  • DFT structures were compared to NMR and EXAFS data to reveal the dominant configuration of the catalyst.

"Revealing the Configuration and Conformation of Surface Organometallic Catalysts with DNP-Enhanced NMR” FA Perras, AL Paterson, ZH Syed, AJ Kropf, DM Kaphan, M Delferro, M Pruski, J. Phys. Chem., C  2021, 125, 13433-13442.