A synchrotron diffraction study of two polymorphic forms of 2, 5-bis

Area of Science:

• Crystallography
• Solid-state chemistry
• Materials science

Background:

• Polymorphism, the ability of a solid material to exist in more than one crystal form, is crucial in determining material properties.
• Understanding the crystal structures of different polymorphs aids in predicting and controlling material behavior.

Purpose of the Study:

• To characterize the crystal structures of the alpha and gamma polymorphs of C(22)H(20)N(2)O(2).
• To investigate the intermolecular interactions governing the packing arrangements in each polymorph.

Main Methods:

• Single-crystal synchrotron X-ray diffraction was employed to determine the precise atomic arrangements.
• Analysis of intermolecular interactions, including hydrogen bonding and van der Waals forces, was performed.

Main Results:

• The alpha polymorph exhibits a herring-bone packing arrangement stabilized by C-H…N interactions.
• The gamma polymorph features molecules arranged in planar sheets connected by C-H…O and C-H…N hydrogen bonds.
• A stacking distance of 3.40 Å was observed between the sheets in the gamma polymorph.

Conclusions:

• The study successfully elucidated the distinct crystal structures and intermolecular interactions of the alpha and gamma polymorphs.
• The findings provide insights into structure-property relationships for C(22)H(20)N(2)O(2), relevant for materials design.