Related Experiment Video
Updated: Jun 8, 2026
06:44
From Molecules to Materials: Engineering New Ionic Liquid Crystals Through Halogen Bonding
Published on: March 24, 2018
Stabilisation of iridium(III) fluoride complexes with NHCs
John Fawcett1, Duncan A J Harding, Eric G Hope
1Department of Chemistry, University of Leicester, Leicester, UK LE1 7RH.
Dalton Transactions (Cambridge, England : 2003)
|October 14, 2010
Summary
This study reports the first synthesis of neutral and cationic iridium(III) fluoride complexes using xenon difluoride. Carbon monoxide (CO) proved a more effective co-ligand than COD for stabilizing these novel iridium complexes.
Area of Science:
- Organometallic Chemistry
- Fluorine Chemistry
- Iridium Complexes
Background:
- Iridium complexes are crucial in catalysis and materials science.
- Synthesis of stable iridium(III) fluoride complexes presents challenges.
- Understanding ligand effects on complex stability is essential.
Purpose of the Study:
- To synthesize novel neutral and cationic iridium(III) fluoride complexes.
- To investigate the stereochemistry and stability of these complexes.
- To evaluate the role of co-ligands (CO vs. COD) in complex stabilization.
Main Methods:
- Synthesis of iridium(III) complexes via xenon difluoride oxidation of iridium(I) precursors.
- Characterization using multinuclear NMR spectroscopy.
- Ligand substitution reactions to attempt synthesis of trifluoroiridium(III) complexes.
Main Results:
- Successful synthesis of the first neutral and cationic NHC iridium(III) fluoride complexes.
- NMR studies confirmed stereochemistry, with no observed fluoride-trans-NHC arrangements.
- Carbonyl (CO) ligands demonstrated superior stabilization compared to cyclooctadiene (COD).
Conclusions:
- Xenon difluoride is an effective reagent for synthesizing iridium(III) fluoride complexes.
- CO is a more effective stabilizing co-ligand than COD for these iridium(III) fluoride complexes.
- Attempts to synthesize neutral trifluoroiridium(III) complexes via ligand substitution were unsuccessful.
Related Concept Videos
03:45Formation of Complex Ions
A type of Lewis acid-base chemistry involves the formation of a complex ion (or a coordination complex) comprising a central atom, typically a transition metal cation, surrounded by ions or molecules called ligands. These ligands can be neutral molecules like H2O or NH3, or ions such as CN− or OH−. Often, the ligands act as Lewis bases, donating a pair of electrons to the central atom. These types of Lewis acid-base reactions are examples of a broad subdiscipline called coordination...
01:09Complexation Equilibria: Factors Influencing Stability of Complexes
In complexation reactions, metal cations are the electron pair acceptors, and the ligands are the electron pair donors. The stability of the metal complexes depends primarily on the complexing ability of the central metal ion and the nature of the ligands. Generally, the complexing ability of the metal ion depends on the size and charge of the ion. As the metal ion size increases, the stability of the metal complexes decreases, provided that the valency of the metal ion and the ligands remain...
02:45Alkyl Halides
Structural Properties
Alkyl halides are halogen-substituted alkanes wherein one or more hydrogen atoms of an alkane is replaced by a halogen atom such as fluorine, chlorine, bromine, or iodine. The carbon atom in an alkyl halide is bonded to the halogen atom, which is sp3-hybridized and exhibits a tetrahedral shape.
Unlike alkyl halides, compounds in which a halogen atom is bonded to an sp2 -hybridized carbon atom of a carbon-carbon double bond (C=C) are called vinyl halides. Whereas aryl...
Alkyl halides are halogen-substituted alkanes wherein one or more hydrogen atoms of an alkane is replaced by a halogen atom such as fluorine, chlorine, bromine, or iodine. The carbon atom in an alkyl halide is bonded to the halogen atom, which is sp3-hybridized and exhibits a tetrahedral shape.
Unlike alkyl halides, compounds in which a halogen atom is bonded to an sp2 -hybridized carbon atom of a carbon-carbon double bond (C=C) are called vinyl halides. Whereas aryl...
02:42Ionic Crystal Structures
Ionic crystals consist of two or more different kinds of ions that usually have different sizes. The packing of these ions into a crystal structure is more complex than the packing of metal atoms that are the same size.
Most monatomic ions behave as charged spheres, and their attraction for ions of opposite charge is the same in every direction. Consequently, stable structures for ionic compounds result (1) when ions of one charge are surrounded by as many ions as possible of the opposite...
Most monatomic ions behave as charged spheres, and their attraction for ions of opposite charge is the same in every direction. Consequently, stable structures for ionic compounds result (1) when ions of one charge are surrounded by as many ions as possible of the opposite...
01:13Electrophilic Aromatic Substitution: Fluorination and Iodination of Benzene
Bromination and chlorination of aromatic rings by electrophilic aromatic substitution reactions are easily achieved, but fluorination and iodination are difficult to achieve. Fluorine is so reactive that its reaction with benzene is difficult to control, resulting in poor yields of monofluoroaromatic products. To address this, Selectfluor reagent is used as a fluorine source in which a fluorine atom is bonded to a positively charged nitrogen.
02:42Valence Bond Theory
Coordination compounds and complexes exhibit different colors, geometries, and magnetic behavior, depending on the metal atom/ion and ligands from which they are composed. In an attempt to explain the bonding and structure of coordination complexes, Linus Pauling proposed the valence bond theory, or VBT, using the concepts of hybridization and the overlapping of the atomic orbitals. According to VBT, the central metal atom or ion (Lewis acid) hybridizes to provide empty orbitals of suitable...