In this work, the direct macrocyclization of a prism[6]arene macrocycle bearing branched alkyl chains on the rims is reported. Isopropoxyprism[6]arene adopts in solution and in the solid state a cuboid D2-conformation in which four isopropyl groups are folded inside the cavity, to give C−H⋅⋅⋅π interactions and filling the internal void. The conformational features of isopropoxyprism[6]arene have been studied by dynamic 1H NMR experiments. The presence of branched isopropyl chains on the prism[6]arene rims, stabilizes the cuboid D2-conformation to a greater extent than ethyl or propyl groups in PrS[6]Et and PrS[6]nPr. The higher resistance of PrS[6]iPr to open its cuboid D2 conformation, with respect to PrS[6]Et and PrS[6]nPr, also affected its binding abilities. In fact, alkylammonium-based endo-cavity complexes of PrS[6]iPr show lower binding constant values than the analogous propoxy/ethoxy-prism[6]arene complexes.

Insights into the Self-Filling Effects of Branched Isopropyl Groups on the Conformational and Supramolecular Properties of Isopropoxyprism[6]arene

Rocco Del Regno
;
Paolo Della Sala;Carmen Talotta;Placido Neri;Carmine Gaeta
2023-01-01

Abstract

In this work, the direct macrocyclization of a prism[6]arene macrocycle bearing branched alkyl chains on the rims is reported. Isopropoxyprism[6]arene adopts in solution and in the solid state a cuboid D2-conformation in which four isopropyl groups are folded inside the cavity, to give C−H⋅⋅⋅π interactions and filling the internal void. The conformational features of isopropoxyprism[6]arene have been studied by dynamic 1H NMR experiments. The presence of branched isopropyl chains on the prism[6]arene rims, stabilizes the cuboid D2-conformation to a greater extent than ethyl or propyl groups in PrS[6]Et and PrS[6]nPr. The higher resistance of PrS[6]iPr to open its cuboid D2 conformation, with respect to PrS[6]Et and PrS[6]nPr, also affected its binding abilities. In fact, alkylammonium-based endo-cavity complexes of PrS[6]iPr show lower binding constant values than the analogous propoxy/ethoxy-prism[6]arene complexes.
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11386/4844874
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