Single electron pnicogen bonded complexes.

Area of Science:

• Computational Chemistry
• Quantum Chemistry
• Chemical Physics

Background:

• Monosubstituted phosphines (XH2P) are versatile molecules in chemistry.
• Methyl radical (CH3) is a key reactive intermediate.
• Understanding their interactions is crucial for reaction mechanisms.

Purpose of the Study:

• To theoretically investigate the complexes formed between monosubstituted phosphines and the methyl radical.
• To characterize the different stable configurations and transition states.
• To elucidate the nature of the bonding interactions.

Main Methods:

• Ab initio computational methods, specifically MP2 and CCSD(T) levels of theory.
• Geometry optimization to locate minima and transition states.
• Analysis of interaction energies and electronic structure.

Main Results:

• Two distinct minima configurations were identified for each XH2P:CH3 complex.
• The first minimum, with short P-C distances, is generally more stable, except for H3P:CH3.
• The second minimum exhibits weak pnicogen bonding, with charge transfer from CH3 to the P-X σ* orbital.

Conclusions:

• The study successfully characterized the complexes, revealing diverse interaction types.
• The findings provide insights into the bonding nature and stability of phosphine-methyl radical adducts.
• Transition states connecting the minima were identified, completing the reaction pathway analysis.