Ethyl acetate: X-ray, solvent and computed structures.

Area of Science:

• Crystallography
• Solid-state chemistry
• Computational chemistry

Background:

• Ethyl acetate (ethyl ethanoate) is a common organic solvent.
• Understanding its solid-state structure and isomer preferences is crucial for various chemical applications.
• Previous studies have not fully characterized the solid-state conformation and disorder of ethyl acetate.

Purpose of the Study:

• To determine the in situ crystal structure of ethyl acetate.
• To statistically analyze the geometric details and isomer preferences of ethyl acetate as a solvate using the Cambridge Structural Database.
• To compare experimental findings with ab initio calculations.

Main Methods:

• In situ crystallization and X-ray diffraction for crystal structure determination.
• Statistical analysis of ethyl acetate solvates from the Cambridge Structural Database.
• Ab initio calculations (DFT-D2 methods) for molecular and solid-state properties.

Main Results:

• The crystal structure of ethyl acetate reveals a flat molecule in a trans conformation.
• Statistical analysis of solvates indicates a strong preference for the trans isomer over gauche and cis isomers, despite considerable hidden disorder.
• Ab initio calculations for molecular structures align with observed isomer preferences, but solid-state calculations show significant deviations from experimental data.

Conclusions:

• Ethyl acetate predominantly adopts a trans conformation in the solid state, with disorder present.
• Computational methods accurately predict molecular isomer preferences but struggle with solid-state properties of ethyl acetate.
• Further refinement of computational methods is needed for accurate solid-state predictions in such systems.