Remote Control of the Synthesis of a [2]Rotaxane and its Shuttling via Metal-Ion Translocation.

ABSTRACT: Remote control in an eight-component network commanded both the synthesis and shuttling of a [2]rotaxane via metal-ion translocation, the latter being easily monitored by distinct colorimetric and fluorimetric signals. Addition of zinc(II) ions to the red colored copper-ion relay station rapidly liberated copper(I) ions and afforded the corresponding zinc complex that was visualized by a bright sky blue fluorescence at 460?nm. In a mixture of all eight components of the network, the liberated copper(I) ions were translocated to a macrocycle that catalyzed formation of a rotaxane by a double-click reaction of acetylenic and diazide compounds. The shuttling frequency in the copper-loaded [2]rotaxane was determined to k ₂₉₈=30?kHz (?H ^?=62.3±0.6?kJ?mol^-1, ?S ^?=50.1±5.1?J?mol^-1?K^-1, ?G ^? ₂₉₈=47.4?kJ?mol^-1). Removal of zinc(II) ions from the mixture reversed the system back generating the metal-free rotaxane. Further alternate addition and removal of Zn²⁺ reversibly controlled the shuttling mode of the rotaxane in this eight-component network where the ion translocation status was monitored by the naked eye.

SUBMITTER: Paul I 

PROVIDER: S-EPMC6863578 | biostudies-literature | 2019 Nov

REPOSITORIES: biostudies-literature