Synthesis of an Adaptable Molecular Barrel and Guest Mediated Stabilization of Its Metastable Higher Homologue

Structural and functional modulation of three-dimensional artificial macromolecular systems is immense importance. Designing supramolecular cages that can show stimuli mediated reversible switching between higher-order structures quite challenging. We report here construction a Pd6 trifacial barrel (1) by coordination self-assembly. Surprisingly, 1 was found to exhibit guest-responsive behavior. In presence fullerenes C60 C70, unprecedentedly transformed its metastable higher homologue Pd8 tetrafacial (2), forming stable host–guest complexes (C60)3⊂2 (C70)2⊂2, respectively. Again, encapsulated could be extracted from the cavity 2 using 1,2-dichlorobenzene, leading facile conversion parent 1. Such structural interconversion an adaptable molecular guest stabilized uncommon observation.