The synthesis and characterization of two 18-crown-6 functionalized analogues of an extensively studied gadolinium texaphyrin derivative, motexafin gadolinium (1, MGd), are reported. These are the monomeric and dimeric species, compounds 2 and 3, respectively. Both crown ether functionalized species proved to be stable at physiological pH and revealed distinct shifts in the UV spectrum when treated with sodium-, potassium-, ammonium- or zinc(II)-salts. Zinc(II) is believed to play a major role regulating apoptosis mechanisms in cancerous cells. Therefore, cytotoxicity studies of 2 and 3 were carried out using the Ramos cell line in the presence and absence of zinc(II).

中文翻译：

---

冠醚功能化泰克萨菲瑞单体和二聚体

报道了广泛研究的钆特沙菲林衍生物莫泰沙芬钆 (1, MGd) 的两种 18-crown-6 功能化类似物的合成和表征。它们分别是单体和二聚体，即化合物 2 和 3。两种冠醚官能化物质均被证明在生理 pH 下稳定，并且在用钠盐、钾盐、铵盐或锌 (II) 盐处理时，紫外光谱显示出明显的变化。锌(II)被认为在调节癌细胞的凋亡机制中发挥着重要作用。因此，在存在和不存在锌(II)的情况下使用Ramos细胞系进行2和3的细胞毒性研究。