Breaking Parallel Orientation of Rods via a Dendritic Architecture toward Diverse Supramolecular Structures

Spherical Supramolecular Structures Constructed via Chemically Symmetric Perylene Bisimides: Beyond Columnar Assembly

Like other discotic molecules, self-assembled supramolecular structures of perylene bisimides (PBIs) are commonly limited to columnar or lamellar structures due to their distinct π-conjugated scaffolds and unique rectangular shape of perylene cores. The discovery of PBIs with supramolecular structures beyond layers and columns may expand the scope of PBI-based materials. A series of unconventional spherical packing phases in PBIs, including A15 phase, σ phase, dodecagonal quasicrystalline (DQC) phase, and body-centered cubic (BCC) phase, is reported. A strategy involving functionalization of perylene core with several polyhedral oligomeric silsesquioxane (POSS) cages achieved spherical assemblies of PBIs, instead of columnar assemblies, due to the significantly increased steric hindrance at the periphery. This strategy may also be employed for the discovery of unconventional spherical assemblies in other related discotic molecules by the introduction of similar bulky functional groups at their periphery. An unusual inverse phase transition sequence from a BCC phase to a σ phase was observed by increasing annealing temperature.

Continuous Curvature Change into Controllable and Responsive Onion-like Vesicles by Rigid Sphere-Rod Amphiphiles

We observe the formation of highly controllable and responsive onion-like vesicles by using rigid sphere-rod amphiphilic hybrid macromolecules, composed of charged, hydrophilic Keggin-type clusters (spheres) and hydrophobic rod-like oligofluorenes (OFs). Unlike the commonly used approach, which mainly relies on chain bending of flexible molecules to satisfy different curvatures in onion-like vesicles, the rigid hybrids form flexible interdigitations by tuning the angles between OFs, leading to the formation of bilayers with different sizes. The self-assembled vesicles possess complete onion-like structures from most inner to outer layers, and their size (layer number) can be accurately manipulated by different solution conditions including solvent polarity, ionic strength, temperature, and hybrid concentration, with fixed interbilayer distance under all conditions. Moreover, the vesicle size (layer number) shows excellent reversibility to the change of temperature. The charged feature of spheres, rod length, and overall hybrid architecture shows significant effects on the formation of such onion-like vesicles.

Magnifying the Structural Components of Biomembranes: A Prototype for the Study of the Self-Assembly of Giant Lipids

How biomembranes are self-organized to perform their functions remains a pivotal issue in biological and chemical science. Understanding the self-assembly principles of lipid-like molecules hence becomes crucial. Herein, we report the mesostructural evolution of amphiphilic sphere-rod conjugates (giant lipids), and study the roles of geometric parameters (head-tail ratio and cross-sectional area) during this course. As a prototype system, giant lipids resemble natural lipidic molecules by capturing their essential features. The self-assembly behavior of two categories of giant lipids (I-shape and T-shape, a total of 8 molecules) is demonstrated. A rich variety of mesostructures is constructed in solution state and their molecular packing models are rationally understood. Giant lipids recast the phase behavior of natural lipids to a certain degree and the abundant self-assembled morphologies reveal distinct physiochemical behaviors when geometric parameters deviate from natural analogues.