A Molecular Capsule with Revolving Doors Partitioning Its Inner Space

Abstract

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"s plit the chamber(380 3)o f1 so that two equally sizeable compartments (190 3)b ecame joined throughac onformationallyf lexible aromatic barrier.T he compartmentso fs uch unique host could be populatedw ith CCl 4 (88 3 ;P C= 46 %), CBr 4 (106 3 ;5 6%)o rt heir combination CCl 4 /CBr 4 (PC = 51 %), with thermodynamic stabilities DG8 tracking the values of packing coefficients (PC). Halogen (CÀX•••p)a nd hydrogen bonding (CÀH•••X) contacts held the haloalkane guests in the cavities of 1.T he consecutivec omplexations were found to occur in an egative allosteric manner,w hich we propose to result from the induced-fit modeo fc omplexation. Newly designed 1 opens aw ay for probingt he effectso fi nner conformational dynamics on noncovalent interactions,r eactivity andi ntramolecular translation in confined spacesofh ollow molecules.