Non-Aqueous Binary and Ternary nHF·Base Fluoride Reagents: Characterization of Structure, Properties, and Reactivity

Area of Science:

• Organic Chemistry
• Fluorination Chemistry
• Physical Chemistry

Background:

• Binary and ternary hydrogen fluoride (HF)·base mixtures are vital nucleophilic fluorinating reagents.
• Their solubility in organic media and tunable reactivity make them valuable in synthesis.
• Ternary mixtures, particularly those involving amines, are frequently used, with composition significantly impacting outcomes.

Purpose of the Study:

• To experimentally and theoretically characterize binary and ternary HF·base mixtures.
• To understand how the ratio of HF to base influences mixture properties and reactivity.
• To provide a quantitative understanding for improved use of these fluorinating agents.

Main Methods:

• Experimental measurements of component concentrations, Hammett acidity (H₀), nucleophilicity, and basicity.
• Theoretical calculations to determine lowest energy cluster structures and sizes.
• Analysis of noncovalent interactions within the HF·base mixtures.

Main Results:

• Detailed characterization of binary and ternary HF·base mixtures across various compositions.
• Correlation between mixture composition (n) and properties like acidity and nucleophilicity.
• Identification of key structural features and noncovalent interactions governing reactivity.

Conclusions:

• The study provides a comprehensive understanding of HF·base mixture properties.
• Quantified data facilitates the rational design and optimization of fluorination reactions.
• Enhanced knowledge supports the broader application of these important reagents in organic synthesis.