Synthesis of an Adaptable Molecular Barrel and Guest Mediated Stabilization of Its Metastable Higher Homologue
Ranit Banerjee, Soumalya Bhattacharyya, Partha Sarathi Mukherjee
Abstract
High Resolution Image Download MS PowerPoint Slide Structural and functional modulation of three-dimensional artificial macromolecular systems is of immense importance. Designing supramolecular cages that can show stimuli mediated reversible switching between higher-order structures is quite challenging. We report here construction of a Pd 6 trifacial barrel ( 1 ) by coordination self-assembly. Surprisingly, barrel 1 was found to exhibit guest-responsive behavior. In presence of fullerenes C 60 and C 70, 1 unprecedentedly transformed to its metastable higher homologue Pd 8 tetrafacial barrel ( 2 ), forming stable host–guest complexes (C 60 ) 3 ⊂ 2 and (C 70 ) 2 ⊂ 2, respectively. Again, encapsulated fullerenes could be extracted from the cavity of 2 using 1,2-dichlorobenzene, leading to its facile conversion to the parent trifacial barrel 1 . Such reversible structural interconversion between an adaptable molecular barrel and its guest stabilized higher homologue is an uncommon observation.