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Determination of Thermodynamic Properties of Alkaline Earth-liquid Metal Alloys Using the Electromotive Force Technique
Published on: November 3, 2017
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Highly Lewis acidic cationic alkaline earth metal complexes.
Jürgen Pahl1, Steffen Brand1, Holger Elsen1
1Inorganic and Organometallic Chemistry, University Erlangen-Nürnberg, Egerlandstrasse 1, 91058 Erlangen, Germany. sjoerd.harder@fau.de.
Chemical Communications (Cambridge, England)
|June 13, 2018
Summary
New cationic magnesium (Mg) and calcium (Ca) complexes featuring β-diketiminate (BDI) ligands exhibit exceptionally strong Lewis acidity. These Lewis acid-free compounds demonstrate reactivity comparable to established strong Lewis acids.
Area of Science:
- Organometallic Chemistry
- Main Group Chemistry
- Lewis Acidity Studies
Background:
- Traditional Lewis acids often involve electron-deficient metal centers.
- β-diketiminate (BDI) ligands are known for stabilizing metal complexes.
- Cationic main group complexes offer unique reactivity profiles.
Purpose of the Study:
- To synthesize and characterize novel cationic Lewis base-free β-diketiminate (BDI) complexes of magnesium (Mg) and calcium (Ca).
- To evaluate the Lewis acidity of the synthesized cationic Mg complex.
- To explore the reactivity of these novel complexes with unsaturated substrates.
Main Methods:
- Synthesis of cationic (BDI)Mg+ and (BDI)Ca+ complexes as B(C6F5)4- salts.
- Spectroscopic characterization (NMR, X-ray crystallography).
- Lewis acidity assessment through adduct formation studies.
Main Results:
- Isolation of Lewis base-free cationic Mg and Ca BDI complexes.
- The (BDI)Mg+ cation displays exceptionally strong Lewis acidity, rivaling known strong Lewis acids like B(C6F5)3.
- Characterization of a 3-hexyne adduct, demonstrating the electrophilic nature of the (BDI)Mg+ cation.
Conclusions:
- Cationic BDI complexes of Mg and Ca can be successfully synthesized.
- The (BDI)Mg+ cation represents a potent new Lewis acid with significant electrophilicity.
- These findings open avenues for exploring new reactivity in main group chemistry.
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