Pathway Control in Cooperative vs. Anti‐Cooperative Supramolecular Polymers

Abstract

Controlling the nanoscale morphology in assemblies of π‐conjugated molecules is key to developing supramolecular functional materials. Here, we report an unsymmetrically substituted amphiphilic PtII complex 1 that shows unique self‐assembly behavior in nonpolar media, providing two competing anti‐cooperative and cooperative pathways with distinct molecular arrangement (long‐ vs. medium‐slipped, respectively) and nanoscale morphology (discs vs. fibers, respectively). With a thermodynamic model, we unravel the competition between the anti‐cooperative and cooperative pathways: buffering of monomers into small‐sized, anti‐cooperative species affects the formation of elongated assemblies, which might open up new strategies for pathway control in self‐assembly. Our findings reveal that side‐chain immiscibility is an efficient method to control anti‐cooperative assemblies and pathway complexity in general.

Quantification of energy of activation to supramolecular nanofibre formation reveals enthalpic and entropic effects and morphological consequence

“…Importantly, we determine the activation thermodynamics in a mixture that evolves rapidly to a metastable state, rather than the nal thermodynamic states that are oen determined in systems such as supramolecular polymers where equilibria are usually implicit. [31][32][33][34] The direct link between thermodynamics of activation of bre formation and the interlinking bre morphology is a result of the solvent composition and temperature, and understanding this threeway relationship can guide material preparation. The implications of the observations are that the formation of materials under conditions far from equilibrium can be controlled through thermodynamic variation achieved through small changes in medium composition and temperature.…”

Kinetically controlled Ag+-coordinated chiral supramolecular polymerization accompanying a helical inversion

“…35,36 In particular, recent advances in kinetic control over the dynamic structural and functional state of the metastable state (i.e., the out-of-equilibrium state) in supramolecular systems has allowed the development of supramolecular polymers with unprecedented structural complexity and sophisticated functionality. [15][16][17][37][38][39][40][41][42][43] Such metastable states, in which spontaneous self-assembly is kinetically suppressed owing to competing aggregation and intramolecular hydrogen bonding, have been utilized to control the self-assembly behavior of supramolecular polymers. 16,40,41 Furthermore, understanding articial supramolecular systems from kinetic perspectives has improved in terms of pathway complexity.…”

Controlled Supramolecular Polymerization of d8 Metal Complexes through Pathway Complexity and Seeded Growth

“…a) Chemical structure of 14; b) schematic depiction of the self-assembly pathways leading to aggregate species A and B. Reproduced from ref[45] with permission. Copyright 2019, Wiley VCH.…”