Department of Chemistry, Life Sciences and Environmental Sustainability, University of Parma, Parco Area delle Scienze 17/a, 43124 Parma, Italy.
Molecules. 2023 Jun 12;28(12):4704. doi: 10.3390/molecules28124704.
Azocalixarenes functionalized with cation binding sites are popular chromoionophores due to the ease of synthesis and the large complexation-induced shifts of their absorption band that originate from an azo-phenol-quinone-hydrazone tautomerism. Despite their extensive use, however, a thorough investigation of the structure of their metal complexes has not been reported. We describe herein the synthesis of a new azocalixarene ligand () and the study of its complexation properties with the Ca cation. Through a combination of solution (H NMR and UV-vis spectroscopies) and solid-state (X-ray diffractometry) techniques, we demonstrate that metal complexation induces a shift of the tautomeric equilibration towards the quinone-hydrazone form, while deprotonation of the complex results in the reversion to the azo-phenol tautomer.
由于合成容易且吸收带的大的配位诱导位移，带有阳离子结合位点的杯[4]芳烃是很受欢迎的变色团，这种位移源于偶氮-苯酚-醌-腙互变异构。然而，尽管它们被广泛使用，但尚未报道对其金属配合物结构的彻底研究。本文描述了一种新的杯[4]芳烃配体（）的合成及其与 Ca 阳离子的络合性质研究。通过溶液（H NMR 和 UV-vis 光谱学）和固态（X 射线衍射法）技术的结合，我们证明金属络合诱导互变异构平衡向醌-腙形式移动，而配合物的去质子化导致回复到偶氮-苯酚互变异构。
