This dissertation focused on the synthesis and characterization of novel model complexes of the [FeFe]-hydrogenase active site containing diselenolato ligands. The substitution of one or two carbonyl groups of Fe2(μ-Se2C3H5CH3)(CO)6 by PPh3, P(OMe)3 or dppe were investigated and leads to syntheses of several [FeFe]-hydrogenase models containing [2Fe2Se] core. Moreover, a series of oxetane-containing diiron dichalcogenolato complexes have been prepared. Diiron model complexes containing mixed (S, Se) or (S, Te) atoms have been also prepared. Diiron Fe2(μ-Se(CH2)xSe-μ)(CO)6 and the tetrairon [Fe2(μ-Se(CH2)ySe-μ)(CO)6]2 model complexes containing selenolato ligands with different length linker (x = 5, 6; y = 4, 5 were also prepared. The electrochemical properties for the newly compounds have been studied to assess their ability to catalyze electrochemical reduction of protons to give dihydrogen. Furthermore, I was gave center of attention on the photoelectron spectroscopy of some compounds. The electronic structure of these complexes is further analyzed with the aid of DFT computations.