Join Zoom Meeting
Meeting ID: 954 0218 6229
Abstract: Metal-Organic Frameworks (MOFs) are a class of highly porous, hybrid, functional and crystalline extended coordination compounds. They show exceptional properties, which render them ideal for a wide range of applications including gas storage and catalysis. Especially for catalysis, MOFs are receiving attraction as well defined supports for organometallic heterogeneous catalysis. Particularly the post-synthetic modifications of secondary building units (SBU) containing hydroxides moieties have gain tremendous interest for the development of supported transition metal catalysts.
The objective of this dissertation is to explore the synthesis, reactivity and functionalization of SBU containing hydroxide units with transition metal catalyst using the Surface Organometallic Chemistry (SOMC) strategy and methods.
The first part of this dissertation gives a detailed application of SOMC strategy to MOFs with the selective grafting of a W(≡CtBu)(CH2tBu)3 complex on the highly crystalline and mesoporous Zr-NU-1000 MOF. The obtained single site material, Zr-NU-1000-W, was characterized using state of the art experimental methods and all the steps leading to the final grafted molecular complex were identified by DFT. Zr-NU-1000-W was active for olefin metathesis and was further fine-tuned by activation with EtAlCl2 giving a more selective and stable catalyst for olefin metathesis.
The second part of the dissertation describes the deliberate design and bulk synthesis of a new zirconium based MOF, Zr-she-MOF-2, and highlights the discovery of a new highly connected MOF based on a careful combination of rare earth (RE) metals with heterobifunctional triangular tetrazole-based ligand, RE-urx-MOF-1. Additionally, the replacement of the tetrazolate functionality by carboxylate, leads to the formation of a different MOF structure RE-gea-MOF-4 having the gea topology with the presence of 18-connected nonanuclear rare earth cluster. Both Zr-she-MOF-2 and RE-gea-MOF-4 present functional SBU and are active for the coupling of epoxides with CO2 to form cyclic carbonate in the presence of Bu4NBr.