Coassembly of Complementary Polyhedral Metal-Organic Framework Particles into Binary Ordered Superstructures.

Here we report the formation of a 3D NaCl-type binary porous superstructure via coassembly of two colloidal polyhedral metal-organic framework (MOF) particles having complementary sizes, shapes, and charges. We employed a polymeric-attenuated Coulombic self-assembly approach, which also facilitated the coassembly of these MOF particles with spherical polystyrene particles to form 2D binary superstructures. Our results pave the way for using MOFs to create sophisticated superstructures comprising particles of various sizes, shapes, porosities, and chemical compositions.

Impact of Molecular Size and Shape on the Supramolecular Co-Assembly of Chiral Tricarboxamides: A Comparative Study.

A comparative investigation of the chiral amplification features of a series of three families of C3 -symmetric tricarboxamides, 1,3,5-triphenylbenzenetricarboxamides (TPBAs), benzenetricarboxamides (BTAs) and oligo(phenylene ethynylene) tricarboxamides (OPE-TAs), is here reported. As previously observed for BTAs and OPE-TAs, a similar dichroic response is obtained for TPBAs decorated with one, two or three chiral side chains bearing stereogenic centers, thus confirming the efficient transfer of point chirality to the supramolecular helical aggregates. Unlike BTAs and OPE-TAs, the chiral amplification ability of TPBAs in majority rules experiments shows a negligible dependence on the number of chiral centers per monomeric unit, and stands the largest among the series of tricarboxamides. Detailed experimental and theoretical studies demonstrate that the rotation angle between the TPBA units in the helical stack is intermediate to that observed for BTAs and OPE-TAs. This feature strongly conditions the steric interactions between vicinal molecules in the stack and the final chiral amplification outcome. Furthermore, theoretical calculations show that achiral side chains favor the interdigitation of the helical aggregates and thereby the formation of bundle superstructures.

Solvent-Directed Helical Stereomutation Discloses Pathway Complexity on N-Heterotriangulene-Based Organogelators.

The chiroptical features of supramolecular polymers formed from N-heterotriangulenes 1-3 have been investigated by circular dichroism (ECD) and vibrational circular dichroism (VCD) techniques. In solution, the CD spectra demonstrate that the helicity of the aggregates depends on only the stereogenic centres located at the peripheral chains. In the gel state, the chiroptical features are conditioned by the point chirality of the stereogenic centres and by the achiral solvent utilised. Sonication of the gels formed in CCl4 reveals both kinetic and thermodynamic phases. These findings reveal the presence of pathway complexity in the gel state triggered by sonication. The described solvent-induced helical stereomutation demonstrates that the gel state can be utilised as an outstanding benchmark for investigating uncommon chiroptical effects and to explore the rules of chirality transmission.