Related Experiment Video
Updated: Dec 28, 2025
09:58
Metal-free Synthesis of Ynones from Acyl Chlorides and Potassium Alkynyltrifluoroborate Salts
Published on: February 24, 2015
11.6K
A Room-Temperature Stable Y(II) Aryloxide: Using Steric Saturation to Kinetically Stabilize Y(II) Complexes
Samuel A Moehring1, Matthias Miehlich2, Christopher J Hoerger2
1Department of Chemistry, University of California, Irvine, California 92697-2025, United States.
Inorganic Chemistry
|February 13, 2020
Summary
Bulky aryloxide ligands stabilize the Y(II) ion, creating a room-temperature stable Y(II) aryloxide. This discovery advances understanding of yttrium chemistry and stable low-valent metal compounds.
Area of Science:
- Inorganic Chemistry
- Organometallic Chemistry
- Materials Science
Background:
- Stabilizing low-valent metal ions is crucial for developing new catalysts and materials.
- Yttrium(II) is a challenging oxidation state to isolate and characterize due to its instability.
- Aryloxide ligands offer steric bulk and electronic tunability for stabilizing reactive metal centers.
Purpose of the Study:
- To investigate the utility of bulky aryloxide ligands for stabilizing the Y(II) ion.
- To compare the stabilizing effects of different aryloxide ligands on Y(II).
- To synthesize and characterize a stable Y(II) aryloxide complex.
Main Methods:
- Synthesis of yttrium(III) aryloxide precursors.
- Reduction of yttrium precursors using potassium graphite (KC8).
- Characterization using X-band Electron Paramagnetic Resonance (EPR) spectroscopy and X-ray crystallography.
Main Results:
- A room-temperature stable Y(II) aryloxide complex, [K(crypt)][Y(OArAd,Ad)3], was successfully synthesized and crystallized.
- The bulky aryloxide ligands (Ad,Ad,MeArO- and Ad,Ad,ArO-) demonstrated superior stabilization of Y(II) compared to less bulky ligands (Ar'O-).
- EPR spectroscopy confirmed the presence of an S = 1/2 spin system consistent with Y(II), showing characteristic axial and isotropic patterns with specific g-values and hyperfine coupling constants.
Conclusions:
- Bulky aryloxide ligands are effective in stabilizing the elusive Y(II) oxidation state.
- The synthesized Y(II) complex is stable at room temperature and amenable to crystallographic characterization.
- This work provides a new route to stable low-valent yttrium compounds with potential applications in catalysis and synthesis.
Related Concept Videos
02:47Alkynes to Aldehydes and Ketones: Hydroboration-Oxidation
20.5K
Introduction
One of the convenient methods for the preparation of aldehydes and ketones is via hydration of alkynes. Hydroboration-oxidation of alkynes is an indirect hydration reaction in which an alkyne is treated with borane followed by oxidation with alkaline peroxide to form an enol that rapidly converts into an aldehyde or a ketone. Terminal alkynes form aldehydes, whereas internal alkynes give ketones as the final product.
One of the convenient methods for the preparation of aldehydes and ketones is via hydration of alkynes. Hydroboration-oxidation of alkynes is an indirect hydration reaction in which an alkyne is treated with borane followed by oxidation with alkaline peroxide to form an enol that rapidly converts into an aldehyde or a ketone. Terminal alkynes form aldehydes, whereas internal alkynes give ketones as the final product.
20.5K
01:10Radical Reactivity: Steric Effects
2.3K
The presence of electron-donating, electron-withdrawing, or conjugating groups adjacent to a radical center, imparts electronic stabilization to the radicals. Examples of such electronically-stabilized radicals are triphenylmethyl, tetramethylpiperidine‐N‐oxide, and 2,2‐diphenyl‐1‐picrylhydrazyl. These radicals are remarkably stable and are known as persistent radicals. Some of the persistent radicals can even be isolated and purified.
Along with electronic...
Along with electronic...
2.3K
01:14Nucleophilic Aromatic Substitution of Aryldiazonium Salts: Aromatic SN1
2.6K
Treating arylamines with nitrous acid gives aryldiazonium salts that are effective substrates in nucleophilic aromatic substitution reactions. The diazonio group in these salts can be easily displaced by different nucleophiles, yielding a wide variety of substituted benzenes. The leaving group departs as nitrogen gas, and this easy elimination is the driving force for the substitution reaction.
In the Sandmeyer reaction, for example, the diazonio group is replaced by a chloro, bromo,...
In the Sandmeyer reaction, for example, the diazonio group is replaced by a chloro, bromo,...
2.6K
01:19Aldehydes and Ketones to Alkenes: Wittig Reaction Overview
9.5K
The Wittig reaction is the conversion of carbonyl compounds-aldehydes and ketones-to alkenes using phosphorus ylides, or the Wittig reagent. The reaction was pioneered by Prof. Georg Wittig, for which he was awarded the Nobel Prize in Chemistry.
9.5K
01:19Types of Enols and Enolates
3.4K
Aldehydes and ketones form enols, although only about 1% of the enol is present at the equilibrium for simple monocarbonyl compounds. The enol form is undetectable for acetaldehyde, present as only 1.5 × 10−4 % of acetone, and present as only 1.2% of cyclohexanone. Two kinds of regioisomeric enols are possible for unsymmetrical ketones, and their net composition is 1% at equilibrium. This instability is due to the lower bond energy of C=C than the C=O group. The additional...
3.4K
01:11Aryldiazonium Salts to Azo Dyes: Diazo Coupling
3.5K
The reaction of weakly electrophilic aryldiazonium (also called arenediazonium) salts with highly activated aromatic compounds leads to the formation of products with an —N=N— link, called an azo linkage. This reaction, presented in Figure 1, is known as diazo coupling and occurs without the loss of the nitrogen atoms of the aryldiazonium salt. Highly activated aromatic compounds such as phenols or arylamines favor the diazo coupling reaction. The coupling generally occurs at the para...
3.5K