A Molecular Capsule with Revolving Doors Partitioning Its Inner Space.

Covalent capsule 1 was designed to include two molecular baskets linked with three mobile pyridines tucked into its inner space. On the basis of both theory (DFT) and experiments (NMR and X‐ray crystallography), we found that the pyridine "doors" split the chamber (380 Å3) of 1 so that two equally sizeable compartments (190 Å3) became joined through a conformationally flexible aromatic barrier. The compartments of such unique host could be populated with CCl4 (88 Å3; PC=46 %), CBr4 (106 Å3; 56 %) or their combination CCl4/CBr4 (PC=51 %), with thermodynamic stabilities ΔG° tracking the values of packing coefficients (PC). Halogen (C−X⋅⋅⋅π) and hydrogen bonding (C−H⋅⋅⋅X) contacts held the haloalkane guests in the cavities of 1. The consecutive complexations were found to occur in a negative allosteric manner, which we propose to result from the induced‐fit mode of complexation. Newly designed 1 opens a way for probing the effects of inner conformational dynamics on noncovalent interactions, reactivity and intramolecular translation in confined spaces of hollow molecules. [ABSTRACT FROM AUTHOR]