Hypergolic Materials Synthesis through Reaction of Fuming Nitric Acid with Certain Cyclopentadienyl Compounds

Abstract

Recently we have shown the importance of hypergolic reactions in carbon materials synthesis. However, hypergolic reactions could be certainly expanded beyond carbon synthesis, offering a general preparative pathway towards a larger variety of materials. Cyclopentadienyls are one of the most common ligands in organometallic chemistry that react hypergolicly on contact with strong oxidizers. By also considering the plethora of cyclopentadienyl compounds existing today, herein we demonstrate the potential of such compounds in hypergolic materials synthesis in general (carbon or inorganic). In a first example, we show that cyclopentadienyllithium reacts hypergolicly with fuming nitric acid to produce carbon. In a second one, we show that ferrocene and cobaltocene also react hypergolicly with the concentrated acid to afford magnetic inorganic materials, such as γ-Fe2O3 and metallic Co, respectively. The present results further emphasize the importance and universal character of hypergolic reactions in materials science synthesis, as an interesting new alternative to other existing and well-established preparative methods.