Functionalized supramolecular assemblies: platform for unlimited opportunities

Design and demonstration of stimuli responsive functional materials through molecular assemblies have seen an upsurge in recent years as the custom made non-covalent host-guest assemblies have found direct relevance in drug delivery/therapeutics, on-off sensors, catalysis, molecular architectures, cooperative and responsive phenomena particularly in biological systems. The presentation will touch upon some of the non-covalent assemblies established by our group using several macrocyclic and macromolecular hosts along with hand-picked organic dyes/inorganic molecules/drugs as guests which have prospects in different utilities such as metal ion separation, sensor applications, chemical intervention of biological functions relevant to therapeutics etc. In this context, photoinduced emissive naphthalene diimide radical anion in the confinement of cucurbituril nanocavity has been demonstrated for in situ generation of gold nanoparticles, having several applications. Using perylene diimide (PDI) derivatives, we demonstrated a large and stable negative differential resistance (NDR) behavior at ambient conditions. The feeble non-covalent interactions are found fascinating when we constructed a novel non-covalently held cucurbit(7)uril-heptamolybdate hybrid material as a generator bed for the facile and efficient separation of ^99mTc radiotracer, which is in demand for theranostic applications. Further, we demonstrated a metal-free supramolecular strategy to increase the hydrolysis rate and yield of hydrogen from ammonia borane by using cucurbit(5/8)uril (CB5/CB8) nanocavitands as catalysts at room temperature. The host-guest interactions were directed to accomplish the inhibition and/or disintegration of amyloid fibrils produced from human insulin and lysozyme proteins. The cavitization strategy has also been used for the cooperative enhancement of antibacterial activity of sanguinarine drug through p-sulfonatocalix(6)arene-functionalized silver nanoparticles. (author)