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Adsorption of metal‐organic complexes on metallic surfaces to produce well‐defined single site catalysts is a novel approach combining the advantages of homogeneous and heterogeneous catalysis. To avoid the "surface trans‐effect" a dome‐shaped molybdenum(0) tricarbonyl complex supported by an tolylazacalix[3](2,6)pyridine ligand is synthesized. This vacuum‐evaporable complex both activates CO and reacts with molecular oxygen (O2) to form a Mo(VI) trioxo complex which in turn is capable of catalytically mediating oxygen transfer. The molybdenum tricarbonyl‐ and trioxo complexes are investigated in the solid state, in homogeneous solution and on noble metal surfaces (Cu, Au) employing a range of spectroscopic and analytical methods. [ABSTRACT FROM AUTHOR]

Adsorption of metal‐organic complexes on metallic surfaces to produce well‐defined single site catalysts is a novel approach combining the advantages of homogeneous and heterogeneous catalysis. To avoid the "surface trans‐effect" a dome‐shaped molybdenum(0) tricarbonyl complex supported by an tolylazacalix[3](2,6)pyridine ligand is synthesized. This vacuum‐evaporable complex both activates CO and reacts with molecular oxygen (O2) to form a Mo(VI) trioxo complex which in turn is capable of catalytically mediating oxygen transfer. The molybdenum tricarbonyl‐ and trioxo complexes are investigated in the solid state, in homogeneous solution and on noble metal surfaces (Cu, Au) employing a range of spectroscopic and analytical methods. [ABSTRACT FROM AUTHOR]

Abstract: Activating small molecules with transition metal complexes adsorbed on metal surfaces is a novel approach combining aspects of homogeneous and heterogeneous catalysis. In order to study the influence of an Au(111) substrate on the activation of the small‐molecule ligand carbon monoxide, a molybdenum tricarbonyl complex containing a PN3P pincer ligand was synthesized and investigated in the bulk, in solution, and adsorbed on an Au(111) surface. By means of a platform approach, a perpendicular orientation of the molybdenum complex was achieved and confirmed by IRRAS and NEXAFS. By using vibrational spectroscopy (IR, Raman, IRRAS) coupled to DFT calculations, the influence of the metal substrate on the activation of the CO ligands bound to the molybdenum complex was determined. The electron‐withdrawing behavior of gold causes an overall shift of the CO stretching vibrations to higher frequencies, which is partly compensated by dynamic charge transfer from the substrate to the molybdenum center, which increases its (dynamic) polarizability. [ABSTRACT FROM AUTHOR]