Английская Википедия:Decamethylferrocene

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Шаблон:Chembox

Decamethylferrocene or bis(pentamethylcyclopentadienyl)iron(II) is a chemical compound with formula Шаблон:Chem2 or Шаблон:Chem2. It is a sandwich compound, whose molecule has an iron(II) cation Шаблон:Chem2 attached by coordination bonds between two pentamethylcyclopentadienyl anions (Шаблон:Chem2, Шаблон:Chem2). It can also be viewed as a derivative of ferrocene, with a methyl group replacing each hydrogen atom of its cyclopentadienyl rings. The name and formula are often abbreviated to DmFc,[1] Шаблон:Chem2 [2] or Шаблон:Chem2.[3]

This compound is a yellow crystalline solid that is used in chemical laboratories as a weak reductant. The iron(II) core is easily oxidized to iron(III), yielding the monovalent cation decamethylferrocenium, and even to higher oxidation states.[3]

Preparation

Decamethylferrocene is prepared in the same manner as ferrocene from pentamethylcyclopentadiene. This method can be used to produce other decamethylcyclopentadienyl sandwich compounds.[4]

2 Li(C5Me5) + FeCl2 → Fe(C5Me5)2 + 2 LiCl

The product can be purified by sublimation. Шаблон:Chem2 has staggered Шаблон:Chem2 rings. The average distance between iron and each carbon is approximately 2.050 Å. This structure has been confirmed by X-ray crystallography.[5]

Redox reactions

Like ferrocene, decamethylferrocene forms a stable cation because Fe(II) is easily oxidized to Fe(III). Because of the electron donating methyl groups on the Шаблон:Chem2 groups, decamethylferrocene is more reducing than is ferrocene. In a solution of acetonitrile the reduction potential for the Шаблон:Chem2 couple is −0.59 V compared to a Шаблон:Chem2 reference (−0.48 V vs Fc/Шаблон:Chem2 in Шаблон:Chem2).[6] Oxygen is reduced to hydrogen peroxide by decamethylferrocene in acidic solution.[7]

Using powerful oxidants (e.g. Шаблон:Chem2 or Шаблон:Chem2 in Шаблон:Chem2, or Шаблон:Chem2 in Шаблон:Chem2) decamethylferrocene is oxidized to a stable dication with an iron(IV) core. In the Шаблон:Chem2 salt, the Шаблон:Chem2 rings are parallel. In contrast, a tilt angle of 17° between the Шаблон:Chem2 rings is observed in the crystal structure of the Шаблон:Chem2 salt.[3]

References