Charge-assisted hydrogen bonding in three diaminobenzene salts

Area of Science:

• Crystal Engineering and Materials Science
• Supramolecular Chemistry
• Solid-State Chemistry

Background:

• Hydrogen-bonding interactions are crucial for designing crystal systems with specific architectures.
• Understanding intermolecular forces is key to controlling the properties of crystalline materials.
• Previous studies have explored related crystalline modifications, highlighting the importance of polymorphism.

Purpose of the Study:

• To report and analyze the crystal structures of benzene-1,2-diaminium sulfate sesquihydrate, benzene-1,3-diaminium tetrachloridozincate(II), and 3-aminoanilinium perchlorate.
• To investigate the role of hydrogen bonding in forming extended structures, including chains and rings.
• To compare intermolecular interactions, such as C...C contacts and hydrogen bonds, using experimental and computational methods.

Main Methods:

• Single-crystal X-ray diffraction was used to determine the crystal structures of the reported salts.
• Hirshfeld surface analysis was employed to quantify and compare intermolecular interactions.
• Density Functional Theory (DFT) calculations were performed to determine interaction energies in 3-aminoanilinium perchlorate.

Main Results:

• The crystal structure of benzene-1,2-diaminium sulfate sesquihydrate was determined as a polymorph of a previously reported salt.
• Extended structures featuring hydrogen-bonded chains and rings (R4^4(8) motif) were observed in multiple compounds.
• Hirshfeld analysis revealed differences in C...C interactions between polymorphs, while DFT indicated stronger aminium-perchlorate interactions in 3-aminoanilinium perchlorate.

Conclusions:

• The study elucidates the diverse hydrogen-bonding networks and intermolecular interactions governing the crystal structures of the investigated organic salts.
• Polymorphism significantly influences crystal packing and intermolecular contacts, as demonstrated by the comparison of two benzene-1,2-diaminium sulfate modifications.
• The findings contribute to the understanding of crystal engineering principles, particularly the role of hydrogen bonding and π-π interactions in directing supramolecular assembly.