ABSTRACT The new macrocyclic ligand L (28,29-dimethoxy-27-oxa-8,11,14,17,25,26-hexaazatetracyclo[22.2.1.1(2,6).1(19,23)]nonacosa-2,4,6(28),19,21,23(29),24,26(1)-octaene) has been synthesised. It contains a tetramine chain and the 2,5-bis(2-methoxy-3-metyl-phenyl)-1,3,4-oxadiazole (PPD-OMe) chromophore, acting as coordinating and sensing units, respectively. The fluorescent emission of L depends on the pH being highly fluorescent at pH = 2 and not emitting from pH >10. The studies highlighted that L is a PET mediated emitting chemosensor, being the PET effect regulated by the degree of the tetraamine protonation. L coordinates metal ions (Cu(II), Zn(II) and Cd(II)) in water giving rise to an OFF-ON fluorescent response for the presence of Zn(II) ion thus signalling its presence in the medium. This response is particularly notable at pH = 9 allowing to extend the Zn(II) sensing also in the alkaline pH field. Graphical abstract

中文翻译：

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用于在碱性 pH 值下检测 Zn(II) 的荧光大环化学传感器

摘要 新的大环配体 L (28,29-dimethoxy-27-oxa-8,11,14,17,25,26-hexaazatetracyclo[22.2.1.1(2,6).1(19,23)]nonacosa-2 ,4,6(28),19,21,23(29),24,26(1)-辛烯）已合成。它包含四胺链和 2,5-双(2-甲氧基-3-甲基-苯基)-1,3,4-恶二唑 (PPD-OMe) 发色团，分别作为配位和传感单元。L 的荧光发射取决于在 pH = 2 时高度荧光的 pH 值，并且在 pH > 10 时不发射。研究强调，L 是一种 PET 介导的发射化学传感器，是由四胺质子化程度调节的 PET 效应。L 与水中的金属离子（Cu(II)、Zn(II) 和 Cd(II)）配位，从而对 Zn(II) 离子的存在产生 OFF-ON 荧光响应，从而表明其在介质中的存在。这种响应在 pH = 9 时特别显着，允许在碱性 pH 场中扩展 Zn(II) 传感。图形概要