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

1,4-disubstituted 1H-1,2,3-triazoles <b>L</b> was successfully synthesised using a catalyst-free click reaction between an internal alkyne and an azide compound. Refluxing click product <b>L</b> and palladium chloride in a homogeneous mixed solvent led to the formation of the non-covalent palladium chloride complex <b>PdCl₂-L₂</b>, 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, <b>PdCl₂-L₂</b> is a monotropic liquid crystal with a narrower mesomorphic temperature range and relatively poorer thermal stability than ligand <b>L</b>. Furthermore, both <b>L</b> and the complex dimer can self-assemble into strip-shaped nanostructures on the oriented graphite substrate surface.

1,4-二取代-1H-1,2,3-三唑（1,4-disubstituted 1H-1,2,3-triazoles）类化合物<b>L</b>通过内炔与叠氮化合物间的无催化剂点击反应成功合成。将点击反应产物<b>L</b>与氯化钯在均相混合溶剂中回流，得到非共价型氯化钯配合物<b>PdCl₂-L₂</b>；通过对模板化合物进行X射线晶体衍射分析表征该配合物，结果显示该配合物主要以反式-反式异构构型存在。两种化合物均展现出层状介晶相的典型扇形织构。由于存在较弱的Pd-N配位键相互作用，配合物<b>PdCl₂-L₂</b>属于单变液晶，其介晶温度范围较配体<b>L</b>更窄，热稳定性也相对更差。此外，配体<b>L</b>与该配合物二聚体均可在定向石墨基底表面自组装形成条状纳米结构。