Related Experiment Video
Updated: Aug 18, 2026

Preparation of SNS Cobalt(II) Pincer Model Complexes of Liver Alcohol Dehydrogenase
Published on: March 19, 2020
Molybdenum pincer complex-based reduction of dinitrogen: mechanistic bifurcation at the stage of Mo(I)-N2
Niels Michaelis1, Tobias A Engesser1, Jan Krahmer1
1Institut für Anorganische Chemie, Christian-Albrechts-Universität zu Kiel, Max-Eyth-Straße 2, 24118 Kiel, Germany. ftuczek@ac.uni-kiel.de.
Abstract:
The synthesis and characterization of a new PPP ligand, bis(di-cyclopentylphosphinoethyl)phenylphosphine (PPP-Cyp), and its derived molybdenum complexes [MoBr3(PPP-Cyp)], [MoNCl2(PPP-Cyp)], [MoNBr2(PPP-Cyp)] and [Mo(η6-toluene)(PPP-Cyp)] are presented. The activities of these compounds towards the catalytic N2RR (nitrogen reduction reaction) and reductive N2 splitting are investigated. A combination of experimental results with DFT calculations elucidates the critical role of the alkyl substituents R at the terminal phosphine donors, which through steric and electronic interactions determine whether Mo(II)- and Mo(I)-N2 intermediates follow a bimolecular pathway, undergoing N-N cleavage, or a monomolecular pathway, undergoing further reduction to Chatt-type Mo(0) complexes. Importantly, these two pathways originate from a common intermediate, [MoX(N2)(PPP-R)], which thus is located at a bifurcation of molybdenum pincer-based N2RR mechanisms.
More Related Videos
Related Concept Videos
Nitriles to Amines: LiAlH4 Reduction
As shown below, the mechanism involves three steps. Firstly, the hydride ion acting as a nucleophile attacks the nitrile carbon to form an anion. In the second step, a second equivalent of the hydride ion attacks the anion to...
Rate-Determining Steps
In a multistep reaction mechanism, one of the elementary steps progresses significantly slower than the others. This slowest step is called the rate-limiting step (or rate-determining step). A reaction cannot proceed faster than its slowest step, and hence, the rate-determining step limits the overall reaction rate.
The concept of rate-determining step can be understood from the analogy of a 4-lane freeway with a short-stretch of traffic-bottleneck caused due to...
Formation of Complex Ions
Amides to Amines: LiAlH4 Reduction
Amide reduction requires two equivalents of the reducing agent, acting as a source of hydride ions. As shown in the figure, the reaction is initiated with a nucleophilic attack by the hydride ion at the carbonyl carbon to form a tetrahedral intermediate.
Benzene to 1,4-Cyclohexadiene: Birch Reduction Mechanism
Multi-Step Reactions

