Supramolecular Chiral Assembly of Symmetric Molecules with an Extended Conjugated Core

Responsive Chirality: Tailoring Supramolecular Assemblies with External Stimuli as Future Platforms for Electronic/Spintronic Materials

Supramolecular chirality is the major branch of supramolecular chemistry, which not only plays important roles in biological processes but also in synthetically designed aggregated systems. To understand the complex processing of biological systems, the only way is to design supramolecular chiral ensembles that mimic natural biomolecules such as Deoxyribonucleic acid (DNA), Ribonucleic acid (RNA), amino acids, etc. In addition, chiral systems and self-assemblies as molecular motifs with breaking spatial inversion symmetry have been regarded as key substances in electronics and spintronics as well as in fundamental chemistry and physics. Here, in this review, our major concern is understanding modulation in spatial arrangements and packing modes under the impact of any external stimuli, which results in tailoring the handedness of resulted supramolecular chiral superstructures. We, in this review, highlighted the role of external stimuli such as solvent, chemical additives, photo exposure, etc. in altering the supramolecular chirality for their future utility as "active switches" in optoelectronic and spintronic devices and applications.

Macrocyclic Diacetylene / Sulfonate Fluorophore Hierarchical Multifunctional Nanotoroids

Functional supramolecular materials exhibit important features including structural versatility and versatile applications. Here, this study reports the construction of unique hierarchically organized nanotoroids exhibiting fluorescence, photocatalytic, and sensing properties. The nanotoroids comprise of macrocyclic diacetylenes (MCDA) and 8-anilino-1-naphthalene sulfonate (ANS), a negatively charged aromatic fluorescent dye. This study shows that the hierarchical structure of the nanotoroids consist of MCDA nanofibers formed by stacked diacetylene monomers as the basic units, which are further bent and aligned into toroidal organization by electrostatic and hydrophobic interactions with the ANS molecules. The amine moieties on the nanotoroids surface are employed for deposition of gold nanostructures - Au nanoparticles or Au nanosheets - which constitute effective platforms for photocatalysis and surface enhanced Raman scattering (SERS)-based sensing.

Remarkable White Circularly Polarized Electroluminescence Based on Chiral Co-assembled Helix Nanofiber Emitters

White circularly polarized organic light-emitting diodes (CP-WOLEDs) are of great significance in potential lighting sources and full-color 3D displays. However, High-performance white CP-EL sources are almost unexplored. We have constructed full-color CP-EL devices based on chiral co-assemblies by using three achiral conjugated pyrene-based dyes (BP, w-WP and c-WP) doped with chiral binaphthyl-based enantiomers (S-/R-M) as the EMLs through an intermolecular chirality induction mechanism. (S-/R-M)_0.2 -(c-WP)_0.8 films exhibit regular helix nanofibers under annealing treatment and emit strong white CPL. Significantly, remarkable CP-WOLEDs based on (S-/R-M)_0.2 -(c-WP)_0.8 were achieved with |g_EL | values as high as 6.2×10^-2 and an excellent CRI of 98 at the CIE coordinates of (0.33, 0.33). These are the highest g_EL and CRI values of reported CP-WOLEDs to date. This is the first achievement of CP-WOLEDs based on chiral co-assembled helix nanofiber emitters, and provides a valuable strategy with which to develop white CP-EL for future practical applications.