Soni Raveena, Bardhan Devjanee, Krishnaswamy Shobhana, Chand Dillip Kumar
IoE Center of Molecular Architecture, Department of Chemistry, Indian Institute of Technology Madras, Chennai, 600036, India.
Chemistry. 2025 Feb 3;31(7):e202403837. doi: 10.1002/chem.202403837. Epub 2024 Dec 10.
A pair of comparable sized C-shaped bis-monodentate ligands (L1 and L2) and a linear bis-monodentate ligand (L3) complementing to the terminal-lengths of the C-shaped ligands have been identified. One-pot combination of cis-Pd(tmeda), L1 and L3 (2 : 1 : 1 ratio) in water resulted an octa-cationic 2-catenane, [Pd(tmeda)(L1)(L3)] in which two identical tetra-cationic macromonocyclic coordination rings are interlocked; however, a guest bound coordination ring was formed in presence of a selected di-anionic guest. Complexation of cis-Pd(tmeda) with a mixture of L2 and L3 (2 : 1 : 1 ratio) in water resulted the hexa-cationic macromonocyclic coordination ring, [Pd(tmeda)(L2)(L3)] whereas a guest bound coordination ring was formed in the presence of the di-anionic guest. Addition of the guest to the preformed octa-cationic catenane caused ring separation to favour the guest-bound ring. This guest bound ring could be reverted to the 2-catenane by sequestering the bound guest using the relatively electron deficient hexa-cationic coordination ring. Thus, a design principle for reversible switching between a 2-catenane and the constituent macromonocyclic-rings using anion-binding/-sequestering as the core concept has been established.
已经鉴定出一对尺寸相当的C形双单齿配体（L1和L2）以及一种与C形配体末端长度互补的线性双单齿配体（L3）。在水中将顺式-Pd（tmeda）、L1和L3以2∶1∶1的比例进行一锅组合，得到一种八阳离子双环烷，[Pd（tmeda）（L1）（L3）]，其中两个相同的四阳离子大环配位环相互锁定；然而，在存在选定的双阴离子客体的情况下会形成客体结合的配位环。在水中将顺式-Pd（tmeda）与L2和L3的混合物以2∶1∶1的比例进行络合，得到六阳离子大环配位环，[Pd（tmeda）（L2）（L3）]，而在双阴离子客体存在的情况下会形成客体结合的配位环。将客体添加到预先形成的八阳离子双环烷中会导致环分离，有利于形成客体结合的环。通过使用相对缺电子的六阳离子配位环螯合结合的客体，可以将这种客体结合的环恢复为双环烷。因此，已经确立了一种以阴离子结合/螯合为核心概念，在双环烷和组成的大环之间进行可逆切换的设计原则。
