Gas phase basicities of polyfunctional molecules. Part 5: Non-aromatic sp² nitrogen containing compounds

Area of Science:

• Physical Chemistry
• Computational Chemistry
• Organic Chemistry

Background:

• This study is the fifth in a series reviewing gas-phase protonation thermochemistry of polyfunctional molecules.
• Focuses on non-aromatic molecules with lone pairs on sp2 hybridized nitrogen atoms.

Purpose of the Study:

• To review and analyze the gas-phase protonation thermochemistry of various nitrogen-containing functional groups.
• To present experimental data re-evaluated on a consistent basicity scale and provide computational insights.

Main Methods:

• Review and re-evaluation of experimental data on protonation energetics.
• Utilized G4MP2 quantum chemistry computations for structural and energetic analysis.
• Organized findings into five major chapters based on functional groups.

Main Results:

• Comprehensive data on the protonation of imines, amidines, guanidines, diazenes, hydrazines, oximes, and phosphazenes.
• Re-evaluated experimental data using a standardized basicity scale (PA(NH3) = 853.6 kJ/mol, GB(NH3) = 819 kJ/mol).
• Presented structural and energetic information from G4MP2 computations.

Conclusions:

• Provides a valuable resource for understanding the protonation behavior of diverse nitrogen-containing functional groups.
• Highlights the importance of computational methods in elucidating thermochemical properties.
• Establishes a consistent dataset for gas-phase protonation of non-aromatic sp2 nitrogen compounds.