Narcissistic self-sorting and enhanced luminescence via catenation in water

Q Chen,Y Lei,H Wang,G Wu,W Xu,T Jiao,Y Pan,Q Zhang,Y.-M Zhang,Y Liu,H Li

doi:10.1016/j.mtchem.2021.100679

Abstract

Narcissistic self-sorting, namely that components are able to distinguish ‘self’ from ‘non-self’ during self-assembly, was accomplished via catenation by condensing multiple hydrazides and an aldehyde, or a hydrazide and multiple aldehydes in water. The underneath mechanism of this behavior relies on the corresponding homo [2]catenanes which are thermodynamically more favored than their hetero counterparts because the former containing two identical macrocyclic components are able to maximize the inter-component non-covalent forces. One of these catenanes contains four 4-phenylpyridinium units, which are often considered barely luminescent because of intramolecular rotations and vibrations that lead to non-radiative annihilation of their excited states. These intramolecular motions, however, are restricted upon integrating 4-phenylpyridiniums within the catenane architecture. As a consequence, compared to its non-interlocked counterparts, this catenane exhibits enhanced fluorescence, which represents a novel conceptual model for developing luminescent materials.

Highlights

Nature employs self-assembly to obtain many functional molecular architectures, such as DNA double strands, and the protein shells of viruses, by gathering many subcomponents together, without the need of performing compound purification or reacting group protection/deprotection
Given that Nature chooses water as the life medium, approaches to accomplish self-sorting in aqueous media must be developed, which helps to fully unravel the underneath mechanisms of the biological events
Different from aggregation-induced emission13 (AIE) materials that often function in solid state, the luminescence enhanced via catenation occurs in a homogeneous solution, where the catenane molecules are homogeneously dispersed

Summary

Introduction

Nature employs self-assembly to obtain many functional molecular architectures, such as DNA double strands, and the protein shells of viruses, by gathering many subcomponents together, without the need of performing compound purification or reacting group protection/deprotection. Combining a 1:1:1 mixture of 1a2+·2Cl─, 2b and 2c in water selectively produced (1a2+·2c)2 as the predominant product, as indicated by the 1H NMR spectrum (Figure S52), leaving 2b unreacted in the solution. Such self-assembly preference did not occur when a 1:1:1 mixture of 1a2+·2Cl─, 2a and 2b was combined in water, which produced both (1a2+·2a)2 and (1a2+·2b)2, as well as their hybridized catenane (1a2+·2a)(1a2+·2b) (Figures S62B and S64).

Results

Conclusion