Self-Assembly of Double-Helical Metallopolymers

Abstract

Conspectus Metal-containing polymers, or metallopolymers, have diverse applications in the fields of sensors, catalysis, information storage, optoelectronics, and neuromorphic computing, among other areas. The approach of metal-templated subcomponent self-assembly using dynamic covalent linkages allows complex architectures to be formed with relative synthetic ease. The dynamic nature of the linkages between subunits in these systems facilitates error checking during the assembly process and also provides a route to disassemble the structure, rendering these materials recyclable. This Account summarizes a class of double-helical metallopolymers. These metallopolymers are formed via subcomponent self-assembly and consist of two conjugated helical strands wrapping a linear array of CuI centers. Starting from discrete model helicates, we discuss how, through the judicious design of subcomponents, long helical metallopolymers can be obtained and detail their subsequent assembly into nanometer-scale aggregates. Two approaches to generate these helical metallopolymers are compared. We describe methods to govern (i) the length of the metallopolymers, (ii) the relative orientations (head-to-head vs head-to-tail) of the two organic strands, and (iii) the screw-sense of the double helix. Achieving structural control allowed the growth behavior of these systems to be probed. The structure influenced properties in ways that are relevant to specific applications; for example, the length of the metallopolymer determines the color of the light it emits in solution. In the solid state, the ionic nature of these helices renders them useful as both emitters and ionic additives in light-emitting electrochemical cells. Moreover, recent experimental work has clarified the role of the linear array of Cu ions in the transport of charge through these materials. The conductivity displayed by a film of metallopolymer depends upon its history of applied voltage and current, behavior characteristic of a memristor. In addition to the prospective applications already identified, others may be on the horizon, potentially combing stimuli-responsive electronic behavior with the chirality of the helical twist.

Synthesis and characterization of novel Al(III)‐metallopolymer and its application as a non‐volatile resistive memristive material

“…Metallopolymers made by coordinating mono/multi‐dentate organic ditopic ligand with transition metal ion have recently expanded interest in material and supramolecular chemistry 1,2 . In these polymers, the organic structure is bonded to a metal ion with coordination bonds as well as a covalent bond through the complexation process 3,4 .…”

“…Metallopolymers made by coordinating mono/multidentate organic ditopic ligand with transition metal ion have recently expanded interest in material and supramolecular chemistry. 1,2 In these polymers, the organic structure is bonded to a metal ion with coordination bonds as well as a covalent bond through the complexation process. 3,4 So, the properties of the metallopolymers can be tuned by tuning the functional group in the organic structure and the change in metal ion in the inorganic part, which changes the electronic, magnetic, and optical properties of functional materials.…”

Solid-State Self-Assembly of Heteroditopic Copillar[5]arenes

“…Owing to the specific, definite, and directional host−guest interactions, heteroditopic monomers has become one of the classic models as building blocks in self-assembly investigation. Driven by the unique multiple CH•••π interactions between the pillar [5]arene cavity and the linear n-alkyl group, copillar [5]arenes have become one of the simplest and optimal models for the construction of heteroditopic monomers in recent years. Here, by comparison of the reported crystal structures of heteroditopic copillar [5]arenes with six new ones (P6Br, P8Br, P6Im, P10Im, P4 ⊃ acetonnitrile, and P8Br ⊃ succinonitrile), we found that their self-assembly manner in the solid state was primarily decided by the competition of the pillar [5]arene cavity between the threading guest moiety and the solvent molecules (or external competitors).…”

“…Since we have already known that P10Br (Figure S7) could spontaneously self-assemble as [c2]daisy chains in the solid state. 50 We first focused on the crystal structures of (P8Br, P6Br, and P4Br) to find out the influence of the linker length on the self-assembly manner of a heteroditopic copillar [5]arene with the same terminal group. After hundreds of attempts, we successfully got the single crystal structures of P8Br and P6Br.…”

“…Just like the solid-state self-assembly of P10Br, 50 two heteroditopic P8Br molecules (Figure 2) formed a cyclic dimer or a [c2]daisy chain, in which the linear n-octyl group of one molecule threaded simultaneously through the electron-rich cavity of the other one. There are five hydrogen atoms on the included octyl group with C−H•••π−plane distances between 2.82 and 2.93 Å, implying the existence of CH•••π interactions between the n-octyl part and the copillar [5]arene cavities (see the red dotted lines in Figure 2). 37,49,50 Similar to the crystal structure of P10Br, the pillar [5]arene cavities are also located on methylenes next to the terminal bromide atoms, leaving the two methylenes next to the oxygen atoms outside, which should be originated from the dispersion forces of the highly polarizable bromide atoms as illustrated by Li and co-workers.…”