1,2,3-Triazole lamellar liquid crystal and its non-covalent palladium complex dimer: structure, mesomorphism and self-assembly properties

ABSTRACT

1,4-disubstituted 1H-1,2,3-triazoles L was successfully synthesised using a catalyst-free click reaction between an internal alkyne and an azide compound. Refluxing click product L and palladium chloride in a homogeneous mixed solvent led to the formation of the non-covalent palladium chloride complex PdCl₂-L₂, which was characterised by X-ray crystallographic analysis of the template compound, indicating that the complex adopts predominant trans-trans isomeric orientations. The two compounds showed a typical fan-shaped texture of the lamellar mesophase. Because of weak Pd-N coordination bond connections, PdCl₂-L₂ is a monotropic liquid crystal with a narrower mesomorphic temperature range and relatively poorer thermal stability than ligand L. Furthermore, both L and the complex dimer can self-assemble into strip-shaped nanostructures on the oriented graphite substrate surface.

Graphical abstract

KEYWORDS:

• 1,2,3-Triazole
• lamellar liquid crystal
• metallomesogens
• click chemistry
• self-assembly

Acknowledgments

The support of this research by the National Natural Science Foundation of China (Fund numbers 51773140 and 51973143) and the Scientific Research Fund of Sichuan Provincial Education Department (Fund numbers 16ZB0059 and 17ZA0346) is gratefully acknowledged.

Disclosure statement

No potential conflict of interest was reported by the author(s).

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Funding

This work was supported by the National Natural Science Foundation of China [51773140, 51973143]; the Scientific Research Fund of Sichuan Provincial Education Department [16ZB0059,17ZA0346].