Halogenated Diazabutadiene Dyes: Synthesis, Structures, Supramolecular Features, and Theoretical Studies

Area of Science:

• Organic Chemistry
• Materials Science
• Supramolecular Chemistry

Background:

• Azo-dyes are important chromophores with diverse applications.
• Halogenated aromatic compounds offer unique electronic and structural properties.
• Understanding non-covalent interactions is key to designing functional materials.

Purpose of the Study:

• To synthesize novel halogenated aromatic dichlorodiazadienes.
• To investigate the role of non-covalent halogen···halogen interactions in their solid-state structure.
• To explore the potential for tuning dye properties through halogen bonding.

Main Methods:

• Copper-mediated oxidative coupling of hydrazones with carbon tetrachloride (CCl4).
• Characterization using Nuclear Magnetic Resonance (NMR) spectroscopy (1H and 13C) and X-ray diffraction.
• Theoretical studies including Density Functional Theory (DFT) calculations and Quantum Theory of Atoms in Molecules (QTAIM) analysis.

Main Results:

• Successful synthesis of novel halogenated aromatic dichlorodiazadienes.
• Detection and characterization of multiple non-covalent halogen···halogen interactions in the solid state.
• DFT calculations confirmed the significant role of these interactions in the self-assembly of the dyes.

Conclusions:

• Non-covalent halogen···halogen interactions are crucial for the self-assembly and solid-state packing of these dichlorodiazadienes.
• Halogen bonding serves as a valuable tool for fine-tuning the properties of this new class of azo-dyes.
• The findings contribute to the rational design of functional organic materials.