Three 46-membered [2 + 2] pendant-armed Schiff-base macrocyclic dinuclear Cd^II and Cu^II complexes (2a, 2b, and 3b) and one 23-membered [1 + 1] Cu^II macrocycle 4a were prepared from the template-directed condensation reactions between 1,2-bis(2-aminoethoxy)-ethane and extended Cl-dialdehyde in the presence of CdX₂ and CuX₂ (X = Cl and Br), in which halide effects play important roles in the organization of final macrocyclic complexes in addition to the dominant influence of metal cations. Transmetalation was intensively studied among these Cd^II and Cu^II complexes with large and flexible macrocyclic ligands, including two previously synthesized dinuclear Zn^II macrocycles (1a and 1b). Our results indicate that Zn^II → Cu^II and Cd^II → Cu^II transmetalation proceeds more quickly than that from Cd^II to Zn^II, and all the processes are found to be irreversible. It is noted that a [2 + 2] heterodinuclear Cd^IIZn^II macrocyclic intermediate could be detected by ESI-MS together with [2 + 2] homodinuclear Cd^II and Zn^II macrocyclic complexes. Furthermore, distinct halide behavior was observed in the in situ Cd^II → Cu^II and Zn^II → Cu^II metal-ion exchange. That is to say, [2 + 2] macrocycles (1a and 2a) could be converted to [1 + 1] macrocycles 4a and 4b under the reflux condition in the case of CuCl₂, accompanied by the configurational transformation from half-folded dinuclear Zn^II and Cd^II to unfolded Cu^II macrocyclic skeleton. In contrast, CuBr₂ leads to a highly efficient transmetalation to corresponding [2 + 2] dinuclear Cu^II complex 3b from both 1b and 2b no matter the experimental condition used.

中文翻译：

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受卤化物影响的柔性链坠席夫基大环配合物的重金属化

从模板中制备了三个46元[2 + 2]悬臂臂席夫碱大环双核Cd ^II和Cu ^II配合物（2a，2b和3b）和一个23元[1 + 1] Cu ^II大环化合物4a。在CdX ₂和CuX ₂（X = Cl和Br）存在下，1,2-双（2-氨基乙氧基）-乙烷与扩展的Cl-二醛之间的直接缩合反应，其中卤化物效应在CdX ₂的组织中起重要作用最终的大环配合物以及金属阳离子的主要影响。在这些Cd ^II和Cu ^II中对重金属化进行了深入研究配合物具有大而灵活的大环配体，包括两个先前合成的双核Zn ^II大环（1a和1b）。我们的结果表明，Zn ^II →Cu ^II和Cd ^II →Cu ^II的重金属化过程比从Cd ^II到Zn ^II的过程更快，并且发现所有过程都是不可逆的。值得注意的是，ESI-MS可以与[2 + 2]同核Cd ^II和Zn ^II一起检测到[2 + 2]异双核Cd ^II Zn ^II大环中间体。大环配合物。此外，在原位Cd ^II →Cu ^II和Zn ^II →Cu ^II金属离子交换中观察到明显的卤化物行为。也就是说，在CuCl ₂的情况下，在回流条件下，[2 + 2]个大环（1a和2a）可以转化为[1 +1]个大环4a和4b，并伴随着半折叠双核的构型转化Zn ^II和Cd ^II形成未折叠的Cu ^II大环骨架。相反，CuBr ₂无论使用何种实验条件，都可从1b和2b高效转化为相应的[2 + 2]双核Cu ^II配合物3b。