Related Experiment Video
Updated: Nov 6, 2025

Diffuse Reflectance Infrared Spectroscopic Identification of Dispersant/Particle Bonding Mechanisms in Functional Inks
Published on: May 8, 2015
Origin of the Ir-Si bond shortening in Ir-NSiN complexes
Pilar García-Orduña1, Israel Fernández2, Luis A Oro1
1Departamento de Química Inorgánica-Instituto de Síntesis Química y Catálisis Homogénea (ISQCH), Universidad de Zaragoza-CSIC, Facultad de Ciencias, 50009 Zaragoza, Spain. paco@unizar.es.
Abstract:
The Ir-Si bond distances reported for Ir-(fac-κ3-NSiNOPy) and Ir-(fac-κ3-NSiN4MeOPy) species (NSiNOPy = bis(pyridine-2-yloxy)methylsilyl and NSiN4MeOPy = bis(4-methyl-pyridine-2-yloxy)methylsily) are in the range of 2.220-2.235 Å. These values are in the lowest limit of the Ir-Si bond distances found in the Cambridge Structural Database (CSD). To understand the origin of such remarkable shortening, a computational study of the bonding situation of representative examples of Ir-(fac-κ3-NSiN) species has been carried out. It is found that the Ir-Si bond can be described as an electron-sharing (i.e. covalent) bond. Despite that, this bond is highly polarized and as a result, the contribution of the electrostatic attractions to the bonding is rather significant. Indeed, there exists a linear relationship (R2 = 0.97) between the Ir-Si bond distance and the extent of the computed electrostatic interactions, which indicates that the ionic contribution to the bonding is mainly responsible for the observed Ir-Si bond shortening.
Related Concept Videos
Valence Bond Theory
Valence Bond Theory
IR Spectrum Peak Intensity: Amount of IR-Active Bonds
IR Spectrum Peak Intensity: Dipole Moment
Structure and Nomenclature of Thiols and Sulfides
Ionic Bonding and Electron Transfer

