2,4-dimethoxybenzoic acid and 2,5-dimethoxybenzoic acid.

Area of Science:

• Organic Chemistry
• Crystallography
• Molecular Structure

Background:

• Benzoic acid derivatives are fundamental organic compounds with diverse applications.
• Understanding their crystal structures and intermolecular interactions is crucial for materials science and drug design.
• Steric and electronic factors significantly influence molecular conformation and hydrogen bonding.

Purpose of the Study:

• To elucidate the crystal structures and hydrogen bonding patterns of 2,5-Dimethoxybenzoic acid (2,5-DMBA) and 2,4-Dimethoxybenzoic acid (2,4-DMBA).
• To investigate the impact of substituent positions on molecular planarity and intermolecular interactions.
• To compare the solid-state behavior of isomers with different methoxy group placements.

Main Methods:

• Single-crystal X-ray diffraction was employed to determine the three-dimensional structures.
• Analysis of hydrogen bonding networks, including bond lengths and angles.
• Comparison of molecular geometries and packing arrangements.

Main Results:

• Both 2,5-DMBA and 2,4-DMBA (C(9)H(10)O(4)) possess nearly planar structures, with substituents deviating from the molecular plane due to steric hindrance.
• 2,5-DMBA uniquely forms an intramolecular hydrogen bond between its carboxylic acid and the adjacent methoxy group (O---O distance: 2.547 Å, angle: 154°).
• 2,4-DMBA exhibits typical intermolecular hydrogen bonding, forming dimers with neighboring molecules.

Conclusions:

• The position of methoxy groups dictates the hydrogen bonding strategy in dimethoxybenzoic acids.
• Intramolecular hydrogen bonding in 2,5-DMBA influences its crystal packing and molecular conformation.
• Isomeric differences lead to distinct solid-state architectures and intermolecular interactions.