Unraveling the Self-Assembly Modes in Multicomponent Supramolecular Gels Using Single-Crystal X-ray Diffraction

Abstract

The control and prediction of the self-assembly process in multicomponent supramolecular gels are challenging because the structure and properties rely mostly on the geometry and spatial arrangement of the building blocks. The understanding of noncovalent interactions between the individual gelators at the molecular level will enable us to tune the gelation properties of multicomponent gels. We have studied the self-assembly process of multicomponent gel based on enantiomers and herin we report the first crystallographic evidence of specific co-assembly in mixed enantiomeric gel, which is supported by scanning electron microscopy and atomic force microscopy images. The mode of interactions between the individual gelators from the molecular to macroscopic level, which are responsible for co-assembled fibers, was identified by single-crystal X-ray diffraction. We have proved that specific co-assembly leads to enhanced mechanical and thermal stability in the mixed gel compared to the meso and individual enantiomeric gels.

Varying the hydrophobic spacer to influence multicomponent gelation

“…[12][13][14][15] Moreover, selective modulation of individual components can be used to modify the gel properties. 13 In short, multicomponent gels are more complex materials than single component gels with enhanced morphogenesis 12,16 and tuneable material properties. 14 Here, we investigate the effect of hydrophobic spacer on gel properties in a multicomponent system.…”

Role of N–Oxide Moieties in Tuning Supramolecular Gel-State Properties

“…We have been successful in identifying the role of various nonbonding interactions in gel formation by comparing the molecular assembly in crystalline and gel/dried gel states [ 30 , 43 , 44 , 45 ]. Although, the xerogel does not represent the exact structure of the gel state since the drying process can lead to a morphological change or phase transition [ 46 ], this approach is still recognized as the most useful strategy to unravel the self-assembly of a gelator [ 3 , 7 , 29 , 30 , 43 , 44 , 45 ]. The self-assembly of L 1 and L 2 in the gel state was correlated with respective crystal structures by comparing the powder X-ray pattern of the bulk crystals and dried gels with the crystal structure.…”

“…The gel to solution transition temperature ( T gel ) was evaluated in different solvent systems using ball-drop method [ 7 , 30 , 44 , 45 ]. The required amount of the gelator was dissolved in the solvent or solvent mixtures by heating the mixture in a sealed vial to obtain a clear solution.…”

Enantioselective Gel Phase Synthesis of Metal–Organic Materials

“…The application of gel phase synthesis in MOMs was analyzed using different gelators and we have chosen the next analogue in the amino acid series, namely valine, and the terephthalic/trimesic amide of valine derivatives [11b, 12a] were synthesized. The reactions performed in the enantiomeric terephthalic amide of valine methyl ester gels ( RR ‐ and SS ‐ValTA) [12a] resulted in MOMs with a similar enantiomeric ratio as RR ‐ and SS ‐AlaTA, respectively (Table S2,S3 and Figure S12,S13).…”