The Knölker complex is an

organoiron compound Organoiron chemistry is the chemistry of iron compounds containing a carbon-to-iron chemical bond. Organoiron compounds are relevant in organic synthesis as reagents such as iron pentacarbonyl, diiron nonacarbonyl and disodium tetracarbonylferrate ...

, which is a catalyst for

transfer hydrogenation In chemistry, transfer hydrogenation is a chemical reaction involving the addition of hydrogen to a compound from a source other than molecular . It is applied in laboratory and industrial organic synthesis to saturate organic compounds and reduc ...

. The complex features an hydroxy

cyclopentadienyl Cyclopentadienyl can refer to * Cyclopentadienyl anion, or cyclopentadienide, ** Cyclopentadienyl ligand * Cyclopentadienyl radical, • * Cyclopentadienyl cation, See also *Pentadienyl In organic chemistry, pentadienyl refers to the organic ...

ligand bound to an Fe(CO)₂H centre. It is generated by the corresponding cyclopentadienone tricarbonyl by treatment with base followed by acidification. The compound is related to the

organoruthenium compound Organoruthenium chemistry is the chemistry of organometallic compounds containing a carbon to ruthenium chemical bond. Several organoruthenium catalysts are of commercial interest and organoruthenium compounds have been considered for cancer therapy ...

called Shvo's complex, a hydroxycyclopentadienyl derivative that also functions as a catalyst for

hydrogenation Hydrogenation is a chemical reaction between molecular hydrogen (H2) and another compound or element, usually in the presence of a catalyst such as nickel, palladium or platinum. The process is commonly employed to reduce or saturate organic c ...

References

{{reflist Organoiron compounds Carbonyl complexes Hydrogenation catalysts Trimethylsilyl compounds Metal hydrides Cyclopentadienyl complexes Half sandwich compounds Iron(II) compounds