Preparation and characterization of diiron diselenolato complexes containing a dioxane ring as models for [FeFe]-hydrogenases

Treatment of Fe 3 (CO) 12 with 5,5-bis(selenocyanatomethyl)-l,3-dioxane in refluxing THF afforded [Fe 2 (μ-Se 2 C 6 H 10 O 2 )(CO) 6 ]. The dimethyl analogue [Fe 2 (μ-Se 2 C 6 H 10 O 2 Me 2 )(CO) 6 ] was obtained from the reaction of Fe 3 (CO) 12 with 5,5-bis(selenocyanatomethyl)-2,2-dimethyl-l,3-dioxane. Both complexes were characterized by spectroscopic techniques. In addition, the solid state structure of [Fe 2 (μ-Se 2 C 6 H 10 O 2 )(CO) 6 ] was determined by single-crystal X-ray analysis. Graphical Abstract Diiron complexes containing dioxan ligand ( 5 and 6 ) of the [FeFe]-hydrogenase active site have been synthesized and characterized. The presence of O atom in the bridged iron cores allows the five-membered ring to which it is attached to be more air stable.