Related Experiment Video
Updated: May 13, 2026

Imine Metathesis by Silica-Supported Catalysts Using the Methodology of Surface Organometallic Chemistry
Published on: October 18, 2019
Si-H activation in an iridium nitrido complex--a mechanistic and theoretical study
1Institut für Anorganische und Angewandte Chemie, Fachbereich Chemie, Universität Hamburg, Martin-Luther-King-Platz 6, 20146 Hamburg, Germany.
Abstract:
Si-H activation in triethyl- and triarylsilanes by a square-planar pyridine-diimine iridium complex with a terminal nitrido unit leads to the corresponding silyl amido complexes, which were unambiguously characterized by X-ray crystallography. Based on detailed combined kinetic and theoretical studies (DFT), direct addition of the Si-H bond to the iridium nitrido unit is proposed. The electronic propensities of the transition states for the Si-H activation were probed with a Hammett series of para-substituted triarylsilanes HSi(C6H5)2(4-C6H4-X). Based on the combination of experimental and theoretical studies, two independent pathways for this process are proposed, which point toward an ambiphilic propensity of the nitrido unit. Alternative pathways and the charge transfer in the transition states were also investigated. Furthermore, the barriers for the related H-H and C-H activation processes in dihydrogen and methane were analyzed.
Related Concept Videos
ortho–para-Directing Activators: –CH3, –OH, –⁠NH2, –OCH3
Structural Isomerism
Isomers are different chemical species that have the same chemical formula. Structural isomerism of coordination compounds can be divided into two subcategories, the linkage isomers and coordination-sphere isomers.
Linkage isomers occur when the coordination compound contains a ligand that can bind to the transition metal center through two different atoms. For example, the CN− ligand can bind through the carbon atom or through the nitrogen atom. Similarly, SCN− can be...
1° Amines to Diazonium or Aryldiazonium Salts: Diazotization with NaNO2 Mechanism
Radical Reactivity: Intramolecular vs Intermolecular
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...
Aldehydes and Ketones with HCN: Cyanohydrin Formation Mechanism

