The Knölker complex is an organoiron compound, which is a catalyst for transfer hydrogenation. The complex features an hydroxycyclopentadienyl ligand bound to an Fe(CO)2H centre. It is generated by the corresponding cyclopentadienone tricarbonyl by treatment with base followed by acidification. It is named for Hans-Joachim Knölker [de] The compound is related to the organoruthenium compound called Shvo's complex, a hydroxycyclopentadienyl derivative that also functions as a catalyst for hydrogenation.
References
Casey, Charles P.; Guan, Hairong (2007). "An Efficient and Chemoselective Iron Catalyst for the Hydrogenation of Ketones". Journal of the American Chemical Society. 129 (18): 5816–5817. doi:10.1021/ja071159f. PMID 17439131. /wiki/Doi_(identifier) ↩
Knölker, Hans-Joachim; Baum, Elke; Goesmann, Helmut; Klauss, Rüdiger (1999). "Demetalation of Tricarbonyl(cyclopentadienone)iron Complexes Initiated by a Ligand Exchange Reaction with NaOH—X-Ray Analysis of a Complex with Nearly Square-Planar Coordinated Sodium". Angewandte Chemie International Edition. 38 (13–14): 2064–2066. doi:10.1002/(SICI)1521-3773(19990712)38:13/14<2064::AID-ANIE2064>3.0.CO;2-W. PMID 34182704. /wiki/Doi_(identifier) ↩
Bullock, R. Morris (2007). "An Iron Catalyst for Ketone Hydrogenations under Mild Conditions". Angewandte Chemie International Edition. 46 (39): 7360–7363. doi:10.1002/anie.200703053. PMID 17847139. https://doi.org/10.1002%2Fanie.200703053 ↩