Sterics and Hydrogen Bonding Control Stereochemistry and Self-Sorting in BINOL-Based Assemblies

Abstract

Here we demonstrate how the hydrogen-bonding ability of a BINOL-based dialdehyde subcomponent dictated the stereochemical outcome of its subsequent self-assembly into one diastereomeric helicate form when bearing free hydroxy groups, and another in the case of its methylated congener. The presence of methyl groups also altered the self-sorting behavior when mixed with another, short linear dialdehyde subcomponent, switching the outcome of the system from narcissistic to integrative self-sorting. In all cases, the axial chirality of the BINOL building block also dictated helicate metal center handedness during stereospecific selfassembly. A new family of stereochemically pure heteroleptic helicates were thus prepared using the new knowledge gained. We also found that switching from Fe II to Zn II , or the incorporation of a longer linear ligand, favored heteroleptic structure formation.

Engineering Homochiral Dinuclear Ir(III)-Metallohelix-Based Porous Molecular Crystals for Atropisomer Enantioseparation

“…The helicity that control and improve the robustness of targeted helicates is key for the development of advanced chiral materials. Typically, the introduction of chiral organic backbones to dictate the stereochemical configurations of stereolabile metal centers could successfully obtain enantiopure helicates. − However, the intrinsic dynamics of the metal–ligand interactions often lead to numbers of possible stereoisomers during the solution coordination process and to the occurrence of unwanted racemization phenomena. , …”

Reversible Co-Self-Assembly and Self-Sorting Systems of Polymer Micelles in Water: Polymers Switch Association Partners in Response to Salts

“…In contrast, all of the PEGMA/DMA random copolymers (P-D10-Np−P-D50-Np) formed fused micelles with C-D50-Py. The yield of a fused micelle increased with the increasing DMA content in their PEG copolymers from 10 to 30 Np (Figure 5b) because P-D10-Np inevitably included quite hydrophilic copolymer chains. These results indicate that the co-self-assembly of C-D50-Py and PEG copolymers is promoted by the increasing hydrophobicity.…”

“…In living organisms, nano- and micro-structured self-assemblies with different structures and functions are simultaneously formed via the precise and dynamic association of amphiphilic biomolecules in complex media. , Those natural self-assemblies are often responsive to environments and external stimuli such as pH and ionic strength to perform functions via the dynamic or reversible transformation of their association structures and partners: gene expression from DNA, transportation of phospholipids between organelles, polymerization of tubulin into microtuble and depolymerization, among many others. − Such a selective multicomponent self-assembly is called “self-sorting”, high-fidelity recognition of self from nonself. − Inspired by nature, chemists have developed artificial self-sorting systems with synthetic molecules such as well-defined supramolecular compounds, in which those molecules are precisely designed to afford specific intra- or intermolecular interactions (e.g., hydrophobic, hydrogen bonding, Π–Π stacking) and recognition by molecular size and shape, steric effects, and chirality. − …”

Unlocking the computational design of metal–organic cages

“…A new level of complexity comes into play when considering the self-sorting 116 of configurational isomers 14 or stereoisomers. 117,118 While design rules can guide structural predictions, unexpected behaviour often occurs, resulting in fascinating MOCs. 12 Therefore, direct structure prediction, without the bias of predetermined outcomes, is necessary for future property prediction and design processes.…”