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Updated: Jan 24, 2026

Preparation of SNS CobaltII Pincer Model Complexes of Liver Alcohol Dehydrogenase
Published on: March 19, 2020
Highly Regio- and Stereoselective Hydrosilylation of Alkynes Catalyzed by Tridentate Cobalt Complexes
Degong Kong1, Bowen Hu1, Dafa Chen1
1MIIT Key Laboratory of Critical Materials Technology, for New Energy Conversion and Storage, Institution School of Chemical Engineering & Technology, Harbin Institute of Technology, Harbin, 150001, P.R. China.
Abstract:
Several cobalt complexes bearing tridentate (NNN) ligands were synthesized and served as precatalysts for alkyne hydrosilylation with Ph2 SiH2 . For terminal alkynes, the catalyst L2 b-CoCl2 was selected, and resulted in the corresponding α-vinylsilanes with high (Markovnikov) regioselectivity and extensive functional-group tolerance. For internal diaryl alkynes, the catalyst L2 c-CoCl2 exhibited the best activity, and afforded E-selective vinylsilanes through syn-addition in excellent yield under mild conditions.
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Related Concept Videos
Alkynes to Aldehydes and Ketones: Acid-Catalyzed Hydration
Analogous to alkenes, alkynes also undergo acid-catalyzed hydration. While the addition of water to an alkene gives an alcohol, hydration of alkynes produces different products such as aldehydes and ketones.
Nomenclature of Alkynes
Formation of Complex Ions
Acid-Catalyzed Ring-Opening of Epoxides
Base-Catalyzed Ring-Opening of Epoxides
Acidity of 1-Alkynes
The acidic strength of hydrocarbons follows the order: Alkynes > Alkenes > Alkanes. The strength of an acid is commonly expressed in units of pKa — the lower the pKa, the stronger the acid. Among the hydrocarbons, terminal alkynes have lower pKa values and are, therefore, more acidic. For example, the pKa values for ethane, ethene, and acetylene are 51, 44, and 25, respectively, as shown here.