Chemistry Seminar — Dr. Steven L. Tait

About the event

Title: Metal-ligand complexation on flat surfaces and on powder supports for single-siteheterogeneous catalysis

Abstract: Self-assembled molecular systems hold great promise for programmed surface functionality. There has been significant development in recent years in using redox-active organic ligands to coordinatesingle transition metal centers in patterned arrays at surfaces. These isolated metal centers at surfaceshave much in common with solution-phase organometallic complexes that function as homogeneouscatalysts. In this talk, I will present recent advances in applying principles of on-surface metalorganic coordination to discover novel single-site heterogeneous catalysts. Model single-crystalsurfaces in ultra-high vacuum allow for detailed investigation by scanning tunneling microscopy, X-ray photoelectron spectroscopy, high-resolution electron energy loss spectroscopy, and X-raystanding way spectroscopy. In an effort to move toward greater complexity in the systems,particularly dinuclear metal centers, our collaborative team has worked toward new ligand designsand assembly strategies. Ligand design impacts the chemical state of the metal centers, in addition tocoordination network structure. In addition to surface science studies of model surfaces, we havealso assembled metal-organic complexes on high surface area powdered oxides through a modifiedwet-impregnation method to generate heterogeneous catalysts for gas phase and solution phasereactions. X-ray photoelectron spectroscopy measurements demonstrate loading of metal and ligandon the surface and synchrotron-based X-ray absorption spectroscopy measurements of thecoordination shell of the metal centers demonstrates single-site stabilization by the ligand. I willdiscuss how fundamental surface science studies and examination of high surface area catalystscomplement each other in advancing catalytic surface functionalization through metal-ligandassembly strategies.