Side Group of Hydrophobic Amino Acids Controls Chiral Discrimination among Chiral Counterions and Metal-Organic Cages.

The self-assembly of chiral PdL metal-organic cages (MOCs) based on hydrophobic amino acids, including alanine (Ala), valine (Val), and leucine (Leu), into single-layered hollow spherical blackberry-type structures is triggered by nitrates through counterion-mediated attraction. In addition to nitrates, anionic -(-butoxycarbonyl) (Boc)-protected Ala, Val, and Leu were used as chiral counterions during the self-assembly of d-MOCs. Previously, we showed that l-Ala suppresses the self-assembly process of d-PdAla but has no effect on l-PdAla, i.

Abnormal Association between Metal-Organic Cages and Counterions Regulated by the Hydration Shells.

A unique trend in the binding affinity between cationic metal-organic cages (MOCs) and external counteranions in aqueous media was observed. Similar to many macroions, two MOCs, sharing similar structures but carrying different number of charges, self-assembled into hollow spherical single-layered blackberry-type structures through counterion-mediated attraction. Dynamic and static light scattering and isothermal titration calorimetry measurements confirm the stronger interactions among less charged MOCs and counteranions than that of highly charged MOCs, leading to larger assembly sizes.

Screw dislocation-induced pyramidal crystallization of dendron-like macromolecules featuring asymmetric geometry.

We report herein that dendron-shaped macromolecules AB crystallize into well-ordered pyramid-like structures from mixed solvents, instead of spherical motifs with curved structures, as found in the bulk. The design of the asymmetric molecular architecture and the choice of mixed solvents are applied as strategies to manipulate the crystallization process. In mixed solvents, the solvent selection for the Janus macromolecule and the existence of dominant crystalline clusters contribute to the formation of flat nanosheets.

Strong Enantiomeric Preference on the Macroion-Counterion Interaction Induced by Weakly Associated Chiral Counterions.

The role of chiral counterions on the attraction and self-assembly of chiral PdL metal organic cages (MOCs) with NO being the original counterion is studied by laser light scattering and isothermal titration calorimetry. Nitrates can trigger the self-assembly of macrocationic PdL into hollow spherical blackberry-type supramolecular structures counterion-mediated attraction. Although chiral counteranions, such as -(-butoxycarbonyl)-alanine (Boc-Ala), have weaker interaction with the MOCs compared to NO, they can induce different assembly behaviors between two enantiomeric MOCs by inhibiting the MOC-nitrate binding and weakening the interaction between them.

Unraveling Chiral Selection in the Self-assembly of Chiral Fullerene Macroions: Effects of Small Chiral Components Including Counterions, Co-ions, or Neutral Molecules.

Lactic acid-functionalized chiral fullerene (C) molecules are used as models to understand chiral selection in macroionic solutions involving chiral macroions, chiral counterions, and/or chiral co-ions. With the addition of Zn cations, the C macroions exhibit slow self-assembly behavior into hollow, spherical, blackberry-type structures, as confirmed by laser light scattering (LLS), transmission electron microscopy (TEM), and atomic force microscopy (AFM) techniques. Chiral counterions with high charge density show no selection to the chirality of AC macroions (LAC and DAC) during their self-assembly process, while obvious chiral discrimination between the assemblies of LAC and DAC is observed when chiral counterions with low charge density are present.