Tetrakis(cyclopentadienyl)uranium(IV), U(C₅H₅)₄, abbreviated U(Cp)₄, is an

organouranium compound Organouranium chemistry is the science exploring the properties, structure, and reactivity of organouranium compounds, which are organometallic compounds containing a carbon to uranium chemical bond. The field is of some importance to the nuclea ...

composed of a uranium atom sandwiched between four

cyclopentadienide Sodium cyclopentadienide is an organosodium compound with the formula C5H5Na. The compound is often abbreviated as NaCp, where Cp− is the cyclopentadienide anion. Sodium cyclopentadienide is a colorless solid, although samples often are pin ...

rings.

Synthesis and properties

Tetrakis(cyclopentadienyl)uranium(IV) was first prepared in 1962 by

Ernst Otto Fischer Ernst Otto Fischer (; 10 November 1918 – 23 July 2007) was a German chemist who won the Nobel Prize for pioneering work in the area of organometallic chemistry. Early life He was born in Solln, a borough of Munich. His parents were Karl T. Fi ...

, who reacted

uranium tetrachloride Uranium tetrachloride is an inorganic compound, a salt of uranium and chlorine, with the formula UCl4. It is a hygroscopic olive-green solid. It was used in the electromagnetic isotope separation (EMIS) process of uranium enrichment. It is one ...

with excess potassium cyclopentadienide in benzene and obtained the complex as red crystals at 6% yield: :UCl₄ + 4 KCp → U(Cp)₄ + 4 KCl Solid crystals of U(Cp)₄ are air-stable, but the benzene solution is extremely air-sensitive. Reduction of U(Cp)₄ with uranium metal yields tris(cyclopentadienyl)uranium(III), U(Cp)₃.

References

{{Authority control Organouranium compounds Metallocenes Cyclopentadienyl complexes Uranium(IV) compounds Substances discovered in the 1960s