ABSTRACT

The well-known lanthanide-binding motif, 2,6-pyridinedicarboxamide, has been functionalised with peripheral substituents using copper-catalysed azide alkyne coupling (CuAAC) to develop new symmetrical ‘clicked’ N₂,N₆-bis((1-(X)-1H-1,2,3,-triazol-4-yl)methyl)pyridine- 2,6-dicarboxamide (where X = ethyl (1) benzyl (2) and 2-naphthyl (3)). These ligands have been successfully coordinated with trivalent lanthanide ions (europium, terbium, and lanthanum) forming [Ln(L)₃](CF₃SO₃)₃ complexes. The ligands act as effective antennae for Eu³⁺ and Tb³⁺ complexes, which exhibit the characteristic sensitised emission profiles. The ability of 1–3 to assemble into 1:3 M:L systems in solution was investigated using UV-Vis, fluorescence, and NMR. Finally, density functional calculations of the ground state La³⁺ complexes have been carried out and show similar geometry and coordination parameters to those with available crystallographic data. The facile and modular synthesis of these ‘clicked’ PDC-based ligands makes these compounds excellent candidates for luminescent supramolecular materials development.

摘要

众所周知的镧系元素结合基序 2,6-吡啶二甲酰胺已使用铜催化叠氮化物炔烃偶联 (CuAAC) 与外围取代基官能化，以开发新的对称“点击”N ₂ ,N ₆ -bis((1-( X)-1H-1,2,3,-三唑-4-基)甲基)吡啶-2,6-二甲酰胺(其中X=乙基( 1 )苄基( 2 )和2-萘基( 3 ))。这些配体已成功地与三价镧系离子（铕、铽和镧）配位，形成[Ln( L ) ₃ ](CF ₃ SO ₃ ) ₃配合物。配体作为 Eu ³⁺和 Tb ^{3+的有效触角}配合物，表现出特征性的敏化发射曲线。使用 UV-Vis、荧光和 NMR 研究了 1-3 在溶液中组装成 1:3 M:L系统的能力。^{最后，对基态 La 3+}配合物进行了密度泛函计算，并显示出与可用晶体学数据相似的几何形状和配位参数。这些“点击”的基于 PDC 的配体的简便和模块化合成使这些化合物成为发光超分子材料开发的优秀候选者。