A journey around iron complexes: ligands design, sustainability, catalytic and bio-inorganic applications

The work described in this thesis has been devoted to the synthesis and study of novel carbonyl iron(0) complexes bearing two type of ligands: cyclopentadienone (CpO) and N-heterocyclic carbene (NHC). Different substituted CpO and NHC have been employed in order to better understand the reactivity of this class of iron compounds. The CpO, supported by the NHC, acts as non-innocent ligand, allowing the oxidation of iron centre from 0 to +2 via an intramolecular redox reaction, generating a new species featuring new properties. The CpO-NHC-iron system has been employed in catalytic reactions such as transfer hydrogenation with poor results and dehydrocoupling of ammonia-borane with interesting results. Electrochemical insights revealed activity as good water oxidation catalyst under basic conditions, which are due to the presence of NHC ligand. Furthermore, the NHC has been exploited as linker to a polymeric thin film coated over an electrode in order to design new chemically modified electrodes (CMEs). A CME has been synthesised and evaluated as glucose sensor. Compounds bearing an amino group on the lateral chain of the NHC ligand have been evaluated as anticancer drugs against pancreatic cancer cells, with an IC50 comparable to Carboplatin. This result is remarkable given the robustness of pancreatic cancer cells. Finally, the reactivity in the hydrogen evolution reaction of a different class of iron compounds (iron dinuclear complexes) has been examined in depth both by DFT calculation and by electrochemical and spectroscopic analysis.