2,3,6,7-Tetra-meth-oxy-9,10-anthra-quinone.

Area of Science:

• Crystallography
• Molecular structure analysis
• Supramolecular chemistry

Background:

• Understanding molecular conformation and crystal packing is crucial for predicting material properties.
• Intermolecular forces, such as pi-pi stacking and hydrogen bonding, dictate crystal lattice formation.
• Detailed structural analysis provides insights into chemical bonding and reactivity.

Purpose of the Study:

• To elucidate the precise three-dimensional molecular structure of the title compound, C18H16O6.
• To investigate the intermolecular interactions and packing arrangements within the crystal lattice.
• To characterize the conformational preferences and symmetry elements of the molecule.

Main Methods:

• Single-crystal X-ray diffraction was employed to determine the molecular and crystal structure.
• Analysis of bond lengths, bond angles, and torsion angles defined the molecular conformation.
• Intermolecular interactions, including pi-pi stacking and C-H...O bonds, were identified and quantified.

Main Results:

• The C18H16O6 molecules exhibit near-planarity with a maximum deviation of 0.096 Å.
• Molecules possess crystallographic centers of inversion and adopt a conformation with specific C-C-O-C torsion angles (-175.3° and 178.2°).
• A slipped-parallel arrangement with pi-pi stacking (inter-planar distance of 3.392 Å) and weak C-H...O interactions forming sheets parallel to (10-2) was observed.

Conclusions:

• The title compound crystallizes with molecules adopting a specific near-planar conformation and inversion symmetry.
• The crystal packing is governed by significant pi-pi stacking interactions and weaker C-H...O hydrogen bonds.
• These structural findings contribute to the understanding of molecular assembly in organic solids.