Photoregulated Living Supramolecular Polymerization Established by Combining Energy Landscapes of Photoisomerization and Nucleation–Elongation Processes

Abstract

The significant contribution of conventional living polymerization to polymer science assures that living supramolecular polymerization will also lead to a variety of novel phenomena and applications. However, the monomer scope still remains limited in terms of the self-assembly energy landscape; a kinetic trap that retards spontaneous nucleation has to be coupled with a supramolecular polymerization pathway, which is challenging to achieve by molecular design. Herein, we report a rational approach to addressing this issue. We combined the supramolecular polymerization and photoisomerization processes to build the energy landscape, wherein the monomer can be activated/deactivated by light irradiation. In this way, the supramolecular polymerization and kinetic trap can be independently designed in the energy landscape. When the "dormant" monomer was activated by light in the presence of the seed of the supramolecular polymer, the "activated" free monomer was polymerized at the termini of the seed in a chain-growth manner. As a result, we achieved supramolecular polymers with controlled lengths and a narrow polydispersity. Although photoisomerization has been extensively employed in supramolecular polymer chemistry, most studies have focused on the stimuli responsiveness. In this respect, the present study would provoke supramolecular chemists to revisit stimuli-responsive supramolecular polymer systems as potential candidates for devising living supramolecular polymerization.

Tunable Energy Landscapes to Control Pathway Complexity in Self‐Assembled N‐Heterotriangulenes: Living and Seeded Supramolecular Polymerization

“…In good correlation with the examples reported in literature, the controlled pathway complexity observed for the reported CBTs 1 – 3 can be utilized to realize living supramolecular polymerization in which the thermodynamically controlled J‐aggregates act as active seeds upon the addition of successive aliquots of kinetically controlled species. To experimentally develop the living supramolecular polymerization of achiral 1 and chiral ( S )‐ 2 , we have followed the methodology described by Takeuchi and co‐workers, evaluating the kinetic evolution of the transformation of the on‐pathway aggregate, in different cycles, upon successive additions of the off‐pathway aggregates (Figure S14, Supporting Information).…”

Direct Observation and Manipulation of Supramolecular Polymerization by High‐Speed Atomic Force Microscopy

“…18 nm) with 2NF to produce ab lock supramolecular copolymer (i.e., 1NF-2NF-1NF,F igure 4a,b). [12][13][14][15][16][17][18][19][20] In fact, two-dimensional seeded supramolecular polymerization, which we reported recently, [9] could also be visualized and manipulated (see Figures S14 and S15). The photochemical "etching" did not occur in the absence of POSS-SH, or if the gap had been repaired with 1NP (see Figures S10 and S11).…”

“…[3,4] In general, such synthetic supramolecular assembly occurs spontaneously and reversibly under thermodynamic control, thereby yielding the most stable structure in terms of free energy.T he resultant nanostructures are usually symmetrical, simple,a nd too small and fragile to manipulate through atop-down approach, which limits the complexity and sophistication of the obtainable materials.One strategy for enhancing the designability of supramolecular assembly is to establish systems under kinetic control. [5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20] We recently identified ak inetically controlled supramolecular assembly consisting of ap orphyrin derivative 1 (Figure 1a). [8][9][10] Porphyrin 1 self-assembles into nanoparticles (1NP), which after several hours of lag time transform into one-dimensional nanofibers (1NF).…”

Photo‐Powered Collapse of Supramolecular Polymers Based on an Overcrowded Alkene Switch

“…Light‐responsive supramolecular polymers are of great importance owing to the clean, fast, non‐invasive and handy character of light stimulus –––. Light‐driven overcrowded alkene switches (OAS) can be designed into a class of well‐known molecular motors which can perform molecular‐scale rotation driven by light and heat, which have been proved reliable in many potential applications, such as asymmetric catalysis, amphiphilic system, ion recognition, and chirality switching .…”