Abstract The present work introduces thiacalix[4]arene adopting 1,3-alternate conformation with alkyl-malonate terminal substituents as ligands for Gd(III) ions. pH-dependent complex formation of Gd(III) ions via alkyl-malonate substituents in aqueous DMSO solutions results in a precipitation. The precipitated complexes were converted into hydrophilic colloids of “plum-pudding” morphology, where the Gd(III) complexes form hard small (1.5–4 nm) cores included into larger (about 180 nm) soft PSS shells. The precipitate-to-colloid transformation is facilitated by polystyrolsulfonate (PSS) for Gd(III) complexes with thiacalix[4]arene bearing propyl-malonate groups, while the presence of PSS triggers a dissolution of the precipitated complexes for thiacalix[4]arenes with pentyl-malonate substituents. To a lesser extent the similar tendency disturbs the formation of PSS-stabilized colloids on the basis of butyl-malonate substituted thiacalix[4]arene. The PSS-stabilized colloids exhibit high longitudinal and transverse relaxivities ( r 1 = 23.8 and r 2 = 29.4 mM −1 s −1 at 0.47 T, respectively), while the recoating of the PSS-stabilized colloids with polyethyleneimine is accompanied by the dissolution of the hard cores. High relaxivity along with low cytotoxicity of PSS-stabilized colloids indicates their applicability as contrast agents in MRI.

中文翻译：

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烷基丙二酸酯取代的硫杯[4]芳烃作为自下而上设计的低细胞毒性含顺磁性含钆(III)胶体的配体

摘要 本工作介绍了硫杯[4]芳烃，其采用1,3-交替构象和烷基丙二酸末端取代基作为Gd(III)离子的配体。Gd(III) 离子通过烷基丙二酸酯取代基在 DMSO 水溶液中形成依赖于 pH 值的复合物导致沉淀。沉淀的复合物被转化为“李子布丁”形态的亲水胶体，其中 Gd(III) 复合物形成坚硬的小 (1.5-4 nm) 核，包含在更大 (约 180 nm) 的软 PSS 壳中。聚苯乙烯磺酸盐 (PSS) 促进了 Gd(III) 与带有丙二酸丙二酸丙酯基团的硫代杯 [4] 芳烃的复合物向胶体的转化，而 PSS 的存在触发了沉淀的硫代杯 [4] 芳烃复合物的溶解带有戊基丙二酸酯取代基。在较小程度上，类似的趋势干扰了基于丙二酸丁酯取代的硫代杯[4]芳烃的 PSS 稳定胶体的形成。PSS 稳定的胶体表现出高纵向和横向弛豫（r 1 = 23.8 和 r 2 = 29.4 mM -1 s -1 在 0.47 T 下），而 PSS 稳定胶体与聚乙烯亚胺的重涂伴随着溶解的硬核。PSS 稳定胶体的高弛豫率和低细胞毒性表明它们可用作 MRI 中的造影剂。而用聚乙烯亚胺重新涂覆 PSS 稳定的胶体伴随着硬核的溶解。PSS 稳定胶体的高弛豫率和低细胞毒性表明它们可用作 MRI 中的造影剂。而用聚乙烯亚胺重新涂覆 PSS 稳定的胶体伴随着硬核的溶解。PSS 稳定胶体的高弛豫率和低细胞毒性表明它们可用作 MRI 中的造影剂。