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Spanning and Expanding the Basicity Scale with Simple Ammonia Derivatives
1Departamento de Química Física Aplicada, Universidad Autónoma de Madrid, Cantoblanco, E-28049 Madrid, Spain.
The Journal of Organic Chemistry
|October 25, 2001
Summary
This study expands the known range of intrinsic basicity by introducing new ammonia derivatives. These compounds, including nitrogen trifluoride and lithium nitride, exhibit significant basicity differences, enabling new chemical reactions.
Area of Science:
- Physical Chemistry
- Computational Chemistry
Background:
- The intrinsic basicity scale quantifies the gas-phase basicity of compounds.
- Existing scales have a defined range, limiting the study of extremely basic or acidic substances.
Purpose of the Study:
- To explore and expand the known range of intrinsic basicity using novel ammonia derivatives.
- To investigate the relationship between substituent electronegativity and the basicity of ammonia derivatives.
- To identify compounds that can bridge the gap between existing acidity and basicity scales.
Main Methods:
- Computational chemistry methods were employed to calculate the intrinsic basicity (DeltaG degrees) of various ammonia derivatives.
- Analysis of the electronic structure and energies of neutral and charged forms of the studied compounds.
Main Results:
- The intrinsic basicity difference between nitrogen trifluoride (F(3)N) and lithium nitride (Li(3)N) was found to be 182 kcal/mol, exceeding the previously known range.
- A series of ammonia derivatives with single-atom substituents of varying electronegativity were shown to span this expanded basicity range.
- The study identified compounds with basicities exceeding that of lithium nitride, classifying it as a superbase.
Conclusions:
- The intrinsic basicity scale can be significantly expanded using carefully designed ammonia derivatives.
- Electronegativity of substituents plays a crucial role in tuning the basicity of ammonia derivatives.
- The newly identified highly basic compounds can be used to bridge the gap between acidity and basicity scales, enabling new gas-phase acid-base reactions.
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