Selective transformation pathways between crystalline forms of an organic material established from powder X-ray...

Area of Science:

• Solid-state chemistry
• Crystallography
• Materials science

Background:

• Benzene-1,2,4,5-tetracarboxylic acid exhibits distinct crystalline phases.
• Solvate phases can transform into other crystalline forms based on environmental conditions.

Purpose of the Study:

• To investigate the solid-state transformation of the methanol solvate crystalline phase (M) of benzene-1,2,4,5-tetracarboxylic acid.
• To elucidate the structural basis for selective phase transitions to hydrate (H) or non-solvate (N) phases.

Main Methods:

• Single-crystal X-ray diffraction was used to determine the crystal structure of the methanol solvate phase (M).
• Powder X-ray diffraction was employed to determine the crystal structure of the non-solvate phase (N).

Main Results:

• The crystal structures of the methanol solvate (M) and non-solvate (N) phases were successfully determined.
• The study provides structural insights correlating with the observed selective transformations to hydrate (H) or non-solvate (N) phases.

Conclusions:

• Understanding the crystal structures of M and N is crucial for comprehending the mechanistic aspects of solid-state transformations.
• The presence of atmospheric water vapor is a key factor influencing the selective phase transition.