Phenanthroline based rotaxanes: recent developments in syntheses and applications

Abstract

The advancements in the field of mechanically interlocked molecular systems (MIMs) has concurrently restructured the material chemistry frontiers and provided ample scope to explore new dimensions for applications and diversity creation.

Metal and Proton Relay-Controlled Hierarchical Multistep Switching Cascade

“…This biologically relevant process and the proton relay it enables were later used by us in designing synthetic systems that exhibit intermolecular communication, catalysis-based amplification, and negative feedback loop function . These examples of intermolecular communication are some of the most complicated, molecular switch-based , synthetic reaction cascades reported, which have recently been supplemented by systems where a combination of metal redox, exchange, and relay are used to communicate between up to three species. − These latter systems, while beautiful, rely on well-established, and sometimes structurally intricate, metal coordination motifs. − Considering the importance of metal exchange and relays (including of protons) in biological systems and the limited structural space of synthetic systems that can mimic such processes, there is a critical need to explore and develop alternative systems that can accomplish similar goals. Here, we report on a hydrazone-based hierarchical multistep switching cascade that combines metal exchange and CCD-induced proton relay (Figure ).…”

Fluorinated [2]rotaxanes with spirofluorene motifs: a non-symmetric distribution of the ring component along the axle component

“…This restricted positioning of dissimilar molecules eventually led to the development of mechanically interlocked molecules (MIMs) like rotaxanes, catenanes, knots, etc. 1,2 The potential applications of these MIMs in general and rotaxanes in particular in various fields like nanoelectronics, polymer chemistry, catalysis and medical science are continuously increasing their traction. 3–7 Accordingly, many synthetic methodologies like template synthesis, self-assembly, or metal mediated coupling reactions were developed to access these attractive targets through efficient ways.…”

“…1a). 1,2 Alternatively, introduction of a bulky substituent in the axle component that acts as a kinetic barrier resulted in the restricted movement of the ring component (Fig. 1b).…”

Controlling the Molecular Shuttling of pH‐Responsive [2]Rotaxanes with Two Different Stations

“…A rotaxane is a supramolecular structure formed by the threading of an axle molecule through the cavity of a macrocyclic molecule that is then sealed at both ends using bulky substituents. [1][2][3] Since the macrocycle of a rotaxane has a high degree of freedom of movement, its molecular motion can be controlled by providing recognition sites on the axle molecule to realize artificial molecular machines. [4][5][6] An example of this type of molecular dynamic is a [2]rotaxane-based molecular shuttle that consists of an axle with two recognition sites and one macrocycle.…”