A new binary carbonyl of iron: the synthesis of Fe4(CO)14 by co-deposition of mass-selected Fe4 with CO

Size-selected Fe4+ was co-condensed with excess CO at low temperatures, resulting in the formation of a previously unknown binary iron carbonyl. Based on its FT-IR spectrum and comparison with isoelectronic congeners, the new species is proposed to be Fe4(CO)14, with a (distorted) tetrahedrally disposed central iron cluster core, three terminal COs on each iron and two doubly bridging carbonyls connecting opposing iron–iron bonds. However, the structure determination is not definitive. The UV–visible absorption spectrum shows two absorption bands centered at 277 and 305 nm.