- Second coordination sphere effects in [FeFe]-Hydrogenase mimics
- Award date
- 22 June 2017
- Number of pages
- Document type
- PhD thesis
- Faculty of Science (FNWI)
- Van 't Hoff Institute for Molecular Sciences (HIMS)
Iron–iron hydrogenase are fascinating metallo‐enzymes able to reversibly perform interconversion between protons and dihydrogen with high rates at low overpotentials. Nevertheless, activity and stability of synthetic analogues without the protein matrix are rarely comparable to the enzyme.
This thesis investigates second coordination sphere effects around synthetic hydrogenase models.
Chapter 2 discusses di‐iron complexes featuring several pyridyl proton‐relays on phosphine ligands. This work demonstrates that proton‐responsive ligands alone are sufficient to achieve high catalytic rates in di‐iron hydrogenase mimics, while the overpotentials remain high.
Chapter 3 presents a straightforward approach for the immobilization of benzene dithiolate di‐iron complexes onto conductive (nano)FTO electrodes.
Specifically, we envision supramolecular M12L24 Fujita‐type cages as a suitable platform to introduce a second coordination sphere around synthetic di‐iron models, emulating the protein environment. Chapter 4 introduces supramolecular M12L24 cages, however this chapter focuses on the preparation of cages featuring redox‐active probes, encapsulated by both supramolecular or covalent strategies, to enable the study of heterogeneous electron transfer processes.
Chapter 5 describes the preparation of a sterically‐demanding molecular electrolyte inhibiting access to the cage cavity. Voltammetric investigation of cages containing redox‐active probes employing this large‐sized electrolyte revealed that these self‐assembled cages bear similarities to macroscopic Faraday cages.
Chapter 6 presents general approaches to introduce a second coordination sphere environment around di‐iron hydrogenases models. We demonstrate for the first time that tuning the local environment around the encapsulated catalyst affords a significantly decreased overpotential, highlighting the importance of the second coordination sphere for catalytic performance.
Thesis (complete) (Embargo until 22 June 2019)
Chapter 2. Proton relay effect in pyridyl appended hydrogenase mimics (Embargo until 22 June 2019)
Chapter 3. Hydrogenase mimics immobilized on FTO electrodes; a strategy towards solar fuel devices (Embargo until 22 June 2019)
Chapter 4. Fundamental studies of electron transfer processes across the rim of M₁₂L₂₄ nano-spheres (Embargo until 22 June 2019)
Chapter 5. Building charges in M₁₂L₂₄ nano-spheres. Does the Faraday principle still hold for molecular objects? (Embargo until 22 June 2019)
Chapter 6. Proton preorganization effect in M₁₂L₂₄ nano-spheres containing hydrogenase mimics (Embargo until 22 June 2019)
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