Imidazolidin-2-one: pseudosymmetry and twinning

Area of Science:

• Crystallography
• Solid-state chemistry
• Molecular structure determination

Background:

• Understanding the precise three-dimensional arrangement of atoms in crystalline solids is fundamental to materials science.
• Previous structural reports for this compound may have been inaccurate, necessitating a definitive analysis.

Purpose of the Study:

• To elucidate the crystal structure of the title compound (C3H6N2O).
• To determine the molecular conformation and intermolecular interactions within the crystal lattice.
• To clarify the correct crystallographic space group and symmetry of the compound.

Main Methods:

• Single-crystal X-ray diffraction analysis was employed.
• The crystal structure was solved and refined.
• Analysis of intermolecular interactions, including hydrogen bonding, was performed.

Main Results:

• The compound C3H6N2O crystallizes in space group I4(1)/a with imposed twofold symmetry.
• The five-membered ring adopts a half-chair conformation.
• N-H···O hydrogen bonds form R2(2)(8) rings and ribbons, with further intersections forming O2H2 rings.
• The crystal was identified as merohedrally twinned.
• The proposed higher symmetry space group I4(1)/amd and the previously reported Fdd2 were shown to be incorrect.

Conclusions:

• The definitive crystal structure of C3H6N2O has been established.
• The molecular conformation and hydrogen bonding network provide insights into its solid-state behavior.
• This work corrects and refines previous structural data for the title compound.