Encapsulation of Iridium Photocatalyst Inside of Silica Nanoparticles for Synthesis Application
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- With the growing concern of climate change and pollution, the landscape of the fine chemical market is changing. Especially in Europe, there are more regulations trying to improve sustainability in the field of fine chemistry. Owing to all those regulations, Europe struggle to keep the pace with the current competitors like China and USA. There is a need to change the ways chemistry used to rely on, to offer more durable chemical processes capable of withstanding the new challenges related to sustainability, highly efficient production rate and quality fine chemicals In this present work, a photocatalytic system will be developed to solve the new challenges of today’s fine chemical industry. That system will be a supported heterogenous photocatalyst. By mixing the power of homogenous photocatalyst and the recyclability of solid-state support, the photocatalytic system becomes more sustainable but also applicable for the field of organic synthesis. The chosen support will be silica because of durability, simple synthesis and chemical inertness. The chosen homogeneous photocatalyst will be a heteroleptic bis-cyclometallated iridium complex constituted of functionalized phenylpyridines as the cyclometallating ligand and bipyridine as an ancillary ligand containing positively charged ammonium group to enhance ionic interaction with the support. This type of photocatalyst has already proved efficiency in fields of material science and most importantly photocatalysis. This work will be split into multiple steps. The first step concern synthesis and characterization of both the homogenous and supported heterogenous system. For the former, UV-visible spectroscopy and NMR analysis of different types of nuclei will be proceeded. For the latter, the composite material will be study extensively through different techniques which will evaluate the textural and structural properties (Dynamic Light Scattering (DLS) analysis, Scanning Electronic Microscopy (SEM) and Brunauer-Emmett-Teller (BET) isotherm analysis) and most importantly the homogeneous photocatalyst linked on the support (Diffuse Reflectance Spectroscopy (DRS), X-ray Photoelectronic Spectroscopy (XPS), Inductively Coupled Plasma – Optical Emission Spectrometry (ICP-OES) and Thermogravimetric Analysis (TGA). The second step will concern the efficiency assessment of the photocatalysts. Homogeneous and heterogeneous will be used in an [2+2] photo-induced intramolecular cycloaddition reaction to evaluate their photocatalytic activity. For the supported photocatalysts, an additional recycling test will be applied. The third step concerns durability assessment. After the recycling test, the heterogeneous photocatalyst will be analyzed a second time to see how much the loading of iridium complex could decrease. The techniques used will be XPS and ICP-OES. During that step, photostability of heterogeneous photocatalyst will be assessed through an UV-visible spectroscopy analysis. And finally, the fourth step will concern the linkage of the heterogeneous photocatalyst onto a support that could be used for flow photochemistry. The supports are free 1D silica nanotubes. The purpose of this step will be to extend the perspective of the project for an application in flow chemistry.