Nanoporous gold functionalized macrocyclic metal complexes for highly efficient photocatalytic oxidations

• Applicants: Dr. Arne Wittstock; Professor Dr. Dieter Wöhrle
• Subject Area: Solid State and Surface Chemistry, Material Synthesis ; Organic Molecular Chemistry - Synthesis and Characterisation
• Term: from 2016 to 2020
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 290346172

In this project macrocyclic metal complexes as photosensitizer will be immobilized onto a high surface area metallic support, the nanoporous gold (npAu). This novel materials combination offers promising applications in the field of heterogeneous photocatalysis. First experimental results indicate an enhancing effect of the metallic substrate onto the photocatalytic activitiy, very much in contrast to inert oxidic supports. Resins for this might be unique optical properties of this metallic support material and will be further investigated in this research project.The following objectives and work packages will be central means:a) Preparation of npAu substrates with different structural sizes (pores and ligaments). This material provides the possibility to finely tune the pore and ligament size between about 30 nm all the way up to microns. This enables us to balance a high porosity and areal concentration of photosensitizer and the mass transport of reactants.b) Synthesis of differently substituted macrocyclic metal-complexes, metallo phthalocyanines (MPc), -subphthalocyanines (MsubPc), and ms-tetraphenylporphyrines (MTpp) which can be bonded onto the npAu substrate with different absorption characteristics and geometries as a central means of studying the interaction between sensitizer and substrate. c) Immobilization of organic entities onto the npAu substrate: Using one- or two-step synthetic procedures (thiol-linker and -spacer units) with different spacing between the metallic centre and the substrate. d) Catalytic investigation of the prepared heterogeneous systems for photooxidation reactions: (I) determination of the efficiency for generating singlet oxygen (quantum yield) for different systems (II) investigating the activity of the system for oxidation of different (industrially important) photoreactions, the oxidation of citronellol and phenol.

• DFG Programme: Research Grants
• Co-Investigator: Professor Dr. Marcus Bäumer