title: Structurally Flexible C₃-Symmetric Receptors for Molecular Recognition and Their Self-Assembly Properties.
abstract: The bioinspired design and synthesis of building blocks and their assemblies by the supramolecular approach has ever fascinated scientists to utilize such artificial systems for numerous purposes. Flexibility is a basic feature of natural systems. However, in artificial systems this is difficult to control, especially if there is no preorganization of the component(s) of a system. We have designed and synthesized a series of C3 -symmetric N-bridged flexible receptors and successfully utilized them to selectively entrap the notorious and toxic nitrate anion in aqueous medium. This was the first report of highest binding affinity for the nitrate anion in aqueous medium. An impressive self-sorting phenomenon of reversibly formed hydrogen-bonded capsules, which self-assembled from flexible tripodal receptors having branches of similar size and bearing the same amide functionality, has been disclosed. Encapsulated nitrate anion has been further utilized for the photochemical [2+2] cycloaddition reaction for the synthesis of strained four-membered ring structures through dynamic self-assembly. In this Personal Account, we summarize these results showing the utility of naturally inspired flexibility in artificial systems.
authors.affiliation: School of Chemical Sciences, National Institute of Science Education and Research (NISER), Institute of Physics Campus, Sachivalaya Marg, Near Sainik School, Bhubaneswar, 751005, India.
authors.forename: Ashutosh S
authors.initials: AS
authors.lastname: Singh
authors.affiliation: Institute of Chemistry, Academia Sinica, 115 Nankang, Taipei, Taiwan. sssun@chem.sinica.edu.tw.
authors.forename: Shih-Sheng
authors.initials: SS
authors.lastname: Sun
mesh_terms: D000838:Anions; D061565:Cycloaddition Reaction; D006860:Hydrogen Bonding; D008958:Models, Molecular; D015394:Molecular Structure; D009566:Nitrates / Q000737:chemistry*; D010472:Perchlorates / Q000737:chemistry; D055668:Photochemical Processes; D062165:Receptors, Artificial / Q000138:chemical synthesis / Q000737:chemistry*; D012997:Solvents; D014867:Water
chemical_list: D000838:Anions; D009566:Nitrates; D010472:Perchlorates; D062165:Receptors, Artificial; D012997:Solvents; D014867:Water
keywords: nitrate anion; photochemistry; receptors; self-assembly; supramolecular chemistry