4-Aryl-3,5-bis(arylethynyl)aryl-4H-1,2,4-triazoles: multitasking skeleton as a self-assembling unit

Area of Science:

• Organic Chemistry
• Materials Science
• Supramolecular Chemistry

Background:

• 1,2,4-triazoles are versatile molecular scaffolds.
• Controlling the self-assembly and macroscopic properties of organic molecules is crucial for materials design.
• Peripheral substitution is a key strategy for tuning molecular behavior.

Purpose of the Study:

• To synthesize novel 4-aryl-3,5-bis(arylethynyl)aryl-4H-1,2,4-triazoles derivatives.
• To investigate the impact of peripheral substitution on the aggregation morphology of these triazoles.
• To explore the structure-property relationships, including optical and mesomorphic behavior.

Main Methods:

• Synthesis of 4-aryl-3,5-bis(arylethynyl)aryl-4H-1,2,4-triazoles.
• Scanning Electron Microscopy (SEM) imaging to analyze aggregate morphology.
• Crystallographic analysis to understand intermolecular interactions.
• Investigation of optical and liquid crystalline properties.

Main Results:

• Paraffinic side chains lead to long fibrillar supramolecular structures.
• Unsubstituted triazoles form thinner ribbons and needle-like aggregates.
• Methoxy-substituted triazoles facilitated a model involving C-H⋅⋅⋅π interactions.
• Triazoles without long side chains showed optical waveguiding.
• Triazoles with peripheral paraffinic side chains exhibited hexagonal columnar mesomorphism.

Conclusions:

• Peripheral substitution dictates the self-assembly behavior and macroscopic properties of 1,2,4-triazoles.
• These molecules act as multitasking scaffolds, exhibiting distinct properties based on their substituents.
• The findings provide insights into designing organic materials with tunable optical and mesomorphic characteristics.