Exploring the full range of N⋯I⋯X halogen-bonding interactions within a single compound using pressure

Area of Science:

• Solid-state chemistry
• Materials science
• Crystallography

Background:

• Trimethylammonium-iodinechloride (TMA-ICl) and diiodide (TMA-I2) are molecular complexes.
• Understanding their structural response to external stimuli is crucial for materials design.

Purpose of the Study:

• To investigate the high-pressure behavior of TMA-ICl and TMA-I2 crystal structures.
• To elucidate the factors contributing to the observed structural flexibility in TMA-ICl.

Main Methods:

• Neutron powder diffraction was employed to analyze crystal structures under high pressure.
• Structural data was compared with existing records in the Cambridge Structural Database.

Main Results:

• TMA-ICl demonstrated significant pressure-induced electronic flexibility.
• N⋯I-Cl interactions in TMA-ICl adapted to encompass a wide range of distances.
• Comparison with TMA-I2 highlighted the role of chlorine's electronegativity in distorting the iodine electron cloud.

Conclusions:

• The electronic flexibility of TMA-ICl is attributed to the influence of the chlorine atom.
• This structural adaptability suggests potential applications in designing novel functional molecular materials.