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Supramolecular Pathway Complexity of a Host-Guest System Revealed in the Single-Crystal Structural Snapshots
Kateryna Kravets1, Mykola Kravets1, Oksana Danylyuk1
1Institute of Physical Chemistry Polish Academy of Sciences, Warsaw, Poland.
None:
The host-guest aqueous complexation gives rise to a library of crystal structures of distinct inclusion modes and solvation states, all assembled from p-sulfonato-calix[4]arene as a host and p-amino-benzamidine as a guest. Benefitting from single-crystal X-ray diffraction analysis and microscopic observation, we show that these host-guest structures emerge progressively from kinetically trapped highly solvated assemblies to thermodynamically favored inclusion complexes as a function of time and concentration. The host-guest system is also highly sensitive to solvent composition, as reflected in the alteration of 1H NMR spectra and crystallization behavior between water-alcohol and purely aqueous solutions. The work illustrates how crystallization can serve as a structural probe of pathway-dependent supramolecular maturation, enabling direct observation of kinetically and thermodynamically accessible assembly states in aqueous host-guest systems.
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