Redox-active ligand controlled selectivity of vanadium oxidation on Au(100)
| Autor: | Christopher D. Tempas, David L. Wisman, Naseem Ud Din, Kenneth G. Caulton, Alexander V. Polezhaev, Duy Le, Tobias W. Morris, Steven L. Tait, Talat S. Rahman, Christopher G. Williams, Miao Wang |
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| Rok vydání: | 2018 |
| Předmět: |
Chemistry
Ligand Vanadium chemistry.chemical_element 02 engineering and technology General Chemistry 010402 general chemistry 021001 nanoscience & nanotechnology Photochemistry 01 natural sciences Redox 0104 chemical sciences Catalysis Transition metal X-ray photoelectron spectroscopy Oxidation state 0210 nano-technology Selectivity |
| Zdroj: | Chemical Science. 9:1674-1685 |
| ISSN: | 2041-6539 2041-6520 |
| Popis: | Metal-organic coordination networks at surfaces, formed by on-surface redox assembly, are of interest for designing specific and selective chemical function at surfaces for heterogeneous catalysts and other applications. The chemical reactivity of single-site transition metals in on-surface coordination networks, which is essential to these applications, has not previously been fully characterized. Here, we demonstrate with a surface-supported, single-site V system that not only are these sites active toward dioxygen activation, but the products of that reaction show much higher selectivity than traditional vanadium nanoparticles, leading to only one V-oxo product. We have studied the chemical reactivity of one-dimensional metal-organic vanadium - 3,6-di(2-pyridyl)-1,2,4,5-tetrazine (DPTZ) chains with O2. The electron-rich chains self-assemble through an on-surface redox process on the Au(100) surface and are characterized by X-ray photoelectron spectroscopy, scanning tunneling microscopy, high-resolution electron energy loss spectroscopy, and density functional theory. Reaction of V-DPTZ chains with O2 causes an increase in V oxidation state from VII to VIV, resulting in a single strongly bonded (DPTZ2-)VIVO product and spillover of O to the Au surface. DFT calculations confirm these products and also suggest new candidate intermediate states, providing mechanistic insight into this on-surface reaction. In contrast, the oxidation of ligand-free V is less complete and results in multiple oxygen-bound products. This demonstrates the high chemical selectivity of single-site metal centers in metal-ligand complexes at surfaces compared to metal nanoislands. |
| Databáze: | OpenAIRE |
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