Surface Deposition of Dome‐Shaped Metal‐Organic Complexes: A New Approach to the Generation of Single‐Site Catalysts

This study describes the synthesis of a new dithia-[2.1.1]-(2,6)-pyridinophane ligand and its molybdenum(0) tricarbonyl complex. Monolayers of the dome-shaped complex on Au(111) are investigated by employing surface spectroscopic methods (infrared reflection absorption spectroscopy, X-ray photoelectron spectroscopy, near-edge X-ray absorption fine structure). A slightly tilted orientation is observed and confirmed. The reactivity toward dioxygen is evaluated and compared to analogous systems.

A novel approach combining the advantages of heterogeneous with those of homogeneous catalysis is the deposition of metal-organic complexes on a metallic surface to create well-defined single-site catalysts. Dome-shaped organometallic complexes with weakly binding coligands are well suited for this purpose. With this in mind, a new dithia-[2.1.1]-(2,6)-pyridinophane ligand has been synthesized. The corresponding molybdenum(0) tricarbonyl complex is structurally and spectroscopically characterized in the bulk and in homogeneous solution. Monolayers of this complex are deposited on Au(111) and investigated with the help of surface spectroscopy (infrared reflection absorption spectroscopy, X-ray photoelectron spectroscopy, and near-edge X-ray absorption fine structure). These methods indicate a slightly tilted orientation of the complex on the gold surface, which is confirmed by density functional theory (DFT) calculations. The reactivity of the complex toward dioxygen is evaluated and compared to analogous complexes supported by aza- and thiacalix[3](2,6)pyridine ligands.

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