Complex Arrangement of Orthogonal Nanoscale Columns via a Supramolecular Orientational Memory Effect

Abstract

Memory effects, including shape, chiral and liquid crystalline, have enabled macroscopic materials with novel functions. However, the generation of complex supramolecular nanosystems via memory effects has not yet been investigated. Here we report a cyclotriveratrylene-crown (CTV) compound that self-assembles into supramolecular columns and spheres forming respectively hexagonal and cubic mesophases. Upon transition from one phase to the other an epitaxial relationship holds, via an unprecedented supramolecular orientational memory effect. Specifically, the molecular orientation and columnar character of supramolecular packing is preserved in the cubic phase, providing an otherwise inaccessible structure comprising orthogonally oriented domains of supramolecular columns. The continuous columnar character of tetrahedrally distorted supramolecular spheres self-organized from the CTV derivative in the faces of the Pm3̅n lattice is the basis of this supramolecular orientational memory, which holds throughout cycling in temperature between the two phases. This concept is expected to be general for other combinations of periodic and quasiperiodic arrays generated from supramolecular spheres upon transition to supramolecular columns.

An Exceptionally Stable and Scalable Sugar–Polyolefin Frank–Kasper A15 Phase

“…[2] Although this reversible thermotropic C$A15 transition has been proposed to proceed in epitaxial fashion, specific mechanistic details are lacking other than to recognize that large structural reorganization of spherical particles within the bulk is not likely to be occurring. [23] Similar transformations of cylinders into stacks of spherical particles have been proposed for block copolymers undergoing an order-order transition between C and body-centered cubic (BCC) phases. [19,24,25] Accordingly,i ti sr easonable to assume as imilar first step in the C!A15 transition pathway for 1, which is further supported by the significant reduction in inter-cylinder spacing that is observed as these domains are presumed to narrow in diameter and elongate prior to "pinching off" to form stacks of spheres.N ext, since ad irect transition between hexagonal and cubic structures is not formally allowed on the basis of symmetry restrictions,small inter-a nd intra-layer displacements can convert an initial hexagonal co-facial layered AAA stacking of spheres into ar hombohedral ABC stacking arrangement.…”

Sequence‐Mandated, Distinct Assembly of Giant Molecules

“…[2] Although the synthesis of sequence-controlled polymers at asimilar level of precision to natural polymers is an enormous endeavor by itself, [3] it remains to be demonstrated how sequence could dictate molecular topology and assembly toward different structures and functions in synthetic polymers. [9] More specifically,t hese giant molecules here refer to precise macromolecules build-up by molecular nanoparticle building blocks.W eh ave previously investigated the effects of composition and topology on the self-assembly of giant molecules. [6] In this case,o ligomers/polymers with nanosized macromonomers [7] is an effective approach to build phase-separated nanostructures with the most significant impact of sequence.…”

“…[6] In this case,o ligomers/polymers with nanosized macromonomers [7] is an effective approach to build phase-separated nanostructures with the most significant impact of sequence.Thei mposing challenge that we are facing is not only to achieve am acromolecule with precisely defined sequences and sizes,b ut also to design and control their self-assembled structures and develop desired properties.Recent advances of click chemistry and other efficient transformations allow scientists to achieve macromolecules with high structural precision and controlled heterogeneity.O nt he other hand, the supramolecular structures are modularly assembled from aset of building blocks and thus the topology and interaction of each building block are critically important to the final assembled structures.T hey,i nt urn, must be accurately determined by the composition and sequence of the macromolecule.A iming at such an enormous task, we begin by rationally designing as eries of model amphiphilic giant molecules (so-called "giant" relative to their small-molecule counterparts) [8] forthe study of sequence-phase relationships and the role of sequences in the formation unconventional phases in soft matters. [9] More specifically,t hese giant molecules here refer to precise macromolecules build-up by molecular nanoparticle building blocks.W eh ave previously investigated the effects of composition and topology on the self-assembly of giant molecules. [4b, 6c, 9d, 10] However,t he importance of sequence has not been systematically explored in terms of their impact on phase formation.Herein, the rational design of model compounds was based on linearly-like configured, monodisperse giant molecules with consecutively connected polyhedral oligomeric…”

Merging Macromolecular and Supramolecular Chemistry into Bioinspired Synthesis of Complex Systems

“…Recently an orientational memory effect was discovered at the transition from A15 and BCC assemblies generated from spherical supramolecular dendrimers or polymers upon cooling into a columnar hexagonal assembly –…”