Supramolecular Depolymerization in the Mixture of Two Poor Solvents: Mechanistic Insights and Modulation of Supramolecular Polymerization of Ionic π‐Systems

Synthesis and Self-assembly of Benzoperylene Benzimidazoles: Tunable Morphology with Aggregation Induced Enhanced Emission

Benzoperylene benzimidazoles ( BPBIs ) based π-systems are synthesized and their self-assembly in both non-polar and polar solvents is investigated. Due to the presence of donor and acceptor functional groups,  BPBIs  absorb light up to 600 nm and display red fluorescence (575-800 nm). Depending on the solvent and side chain,  BPBIs  self-assemble into various nanostructures such as nanoribbons, nanorods, nanofibers and nanoparticles. Notably, these ordered nanostructures are formed by  BPBIs  in both polar and non-polar solvents   without the aid of hydrogen bonding and amphiphilic interactions due to the presence of a large rigid π-system. Interestingly,  BPBIs  follow a weakly cooperative mechanism during the self-assembly. Moreover,  BPBIs  show aggregation induced enhanced emission (AIEE) in all the self-assembled nanostructures which is not common for rigid π-systems.

Controlling the length of porphyrin supramolecular polymers via coupled equilibria and dilution-induced supramolecular polymerization

Multi-component systems often display convoluted behavior, pathway complexity and coupled equilibria. In recent years, several ways to control complex systems by manipulating the subtle balances of interaction energies between the individual components have been explored and thereby shifting the equilibrium between different aggregate states. Here we show the enantioselective chain-capping and dilution-induced supramolecular polymerization with a Zn²⁺-porphyrin-based supramolecular system when going from long, highly cooperative supramolecular polymers to short, disordered aggregates by adding a monotopic Mn³⁺-porphyrin monomer. When mixing the zinc and manganese centered monomers, the Mn³⁺-porphyrins act as chain-cappers for Zn²⁺-porphyrin supramolecular polymers, effectively hindering growth of the copolymer and reducing the length. Upon dilution, the interaction between chain-capper and monomers weakens as the equilibria shift and long supramolecular polymers form again. This dynamic modulation of aggregate morphology and length is achieved through enantioselectivity in the aggregation pathways and concentration-sensitive equilibria. All-atom and coarse-grained molecular simulations provide further insights into the mixing of the species and their exchange dynamics. Our combined experimental and theoretical approach allows for precise control of molecular self-assembly and chiral discrimination in complex systems.

Sidechain engineering of N-annulated perylene diimide molecules

Six new N-annulated perylene diimide molecules are reported with varied pyrrolic N-atom sidechains. Impact on optoelectronic and physical properties is investigated.