Synthetic models of the active site of [FeFe]-hydrogenase containing naphthalene monoimide (NMI) of peri-substituted dichalcogenides as bridging linkers have been prepared and characterized using different spectroscopic methods. The influence of the imide functionality and the chalcogen atoms on the redox properties and the catalytic behaviour of complexes 7–10 was studied using cyclic voltammetry. The results revealed that the imide functionality has improved the chemical stability of the reduced species and the replacement of the S atoms by Se caused a cathodic shift in the oxidation peaks. Moreover, the optical properties of compounds 1, 2, 4, and 5 and the respective diiron complexes 7–10 were investigated by UV-Vis absorption and fluorescence spectroscopy assisted by quantum chemical simulations. The structures of complexes 6–9 were confirmed by X-ray diffraction analysis.

The synthetic models of the active site of an [FeFe]-hydrogenase containing a Sn atom in the bridgehead of the diselenato ligand, namely [Fe ₂ (CO) ₆ {μ-(SeCH ₂ Se)SnMe ₂ }], 3 and [Fe ₂ (CO) ₆ {μ-(SeCH ₂ ) ₂ SnMe ₂ }], 4 have been synthesized and characterized by spectroscopic methods.