Quantitative analysis of solid-state diversity in trifluoromethylated phenylhydrazones

Area of Science:

• Crystal Engineering
• Supramolecular Chemistry
• Organic Solid-State Chemistry

Background:

• Understanding intermolecular interactions is crucial for designing molecular crystals.
• Trifluoromethylated phenylhydrazones offer a versatile scaffold for studying crystal packing.
• Polymorphism can significantly influence material properties.

Purpose of the Study:

• To investigate the role of structural motifs and intermolecular interactions in the formation of molecular crystals.
• To analyze the cooperative effects of various interactions in trifluoromethylated phenylhydrazones.
• To characterize the supramolecular constructs and their stability.

Main Methods:

• Single-crystal and powder X-ray diffraction.
• Differential scanning calorimetry.
• Quantum theory of atoms in molecules (QTAIM) for topological analysis.

Main Results:

• Two compounds showed 3D structural similarities with equivalent building blocks.
• One compound exhibited polymorphism, with different crystal forms at low and room temperatures.
• Dispersion forces and C-H...π interactions were primary stabilizers, with weak interactions (N-H...F, C-H...F, F...F, etc.) providing additional stability.
• Interaction energies ranged from -29 to -43 kJ/mol for stabilizing blocks.

Conclusions:

• Supramolecular assemblies in these phenylhydrazones are mainly driven by dispersion energy and C-H...π interactions, rather than strong hydrogen bonding.
• Weak interactions play a significant role in stabilizing the overall crystal packing.
• QTAIM analysis confirmed the nature and stability of atomic interactions in the solid state.