Redox-Active Ligand Controlled Selectivity Of Vanadium Oxidation On Au(100)

Abstract

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.

Publication Date

1-1-2018

Publication Title

Chemical Science

Volume

9

Issue

6

Number of Pages

1674-1685

Document Type

Article

Personal Identifier

scopus

DOI Link

https://doi.org/10.1039/c7sc04752e

Socpus ID

85041532798 (Scopus)

Source API URL

https://api.elsevier.com/content/abstract/scopus_id/85041532798

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