title: Preferential molecular encapsulation of an ICT fluorescence probe in the supramolecular cage of cucurbit[7]uril and β-cyclodextrin: an experimental and theoretical approach.
abstract: Supramolecular interaction between an intramolecular charge transfer (ICT) probe, N,N-dimethylaminonaphthyl-(acrylo)-nitrile (DMANAN), and two well-recognized macrocyclic hosts, cucurbit[7]uril (CB7) and β-cyclodextrin (β-CD), has been studied in aqueous medium by absorption, emission, time-resolved measurements, and (1)H NMR spectroscopic methods. The changes in the profiles of the fluorescence spectra illustrate significant modifications in fluorescence intensity, decay time, and quantum yield upon confinement of probe within the hydrophobic cavity of the hosts. Using the Benesi-Hildebrand relationship, the stoichiometric ratio as well as the binding constant of the host-guest complexation has been estimated. The stable inclusion complexes of the probe with different hosts have been supported by DFT and ONIOM based quantum chemical calculations. These methods of measurement establish that the acceptor group of the probe resides inside the hydrophobic cavity of the macrocycle. The competitive binding of metal ions and cationic surfactants to CB7 has been excellently mapped with this guest fluorosensor.
authors.affiliation: Department of Chemistry, Jadavpur University , Raja S. C. Mallick Road, Kolkata 700 032, India.
authors.forename: Anuva
authors.initials: A
authors.lastname: Samanta
authors.forename: Nikhil
authors.initials: N
authors.lastname: Guchhait
authors.forename: Subhash Chandra
authors.initials: SC
authors.lastname: Bhattacharya
mesh_terms: D015057:1-Naphthylamine / Q000031:analogs & derivatives / Q000737:chemistry; D001952:Bridged-Ring Compounds / Q000737:chemistry*; D005456:Fluorescent Dyes / Q000737:chemistry*; D007093:Imidazoles / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D008958:Models, Molecular; D009570:Nitriles / Q000737:chemistry; D013050:Spectrometry, Fluorescence; D014867:Water / Q000737:chemistry; D047392:beta-Cyclodextrins / Q000737:chemistry*; D047028:Macrocyclic Compounds; D000099246:Cucurbit(n)urils
chemical_list: D015057:1-Naphthylamine; D001952:Bridged-Ring Compounds; D005456:Fluorescent Dyes; D007093:Imidazoles; D009570:Nitriles; D014867:Water; D047392:beta-Cyclodextrins; C559461:N,N-dimethylaminonapthyl-(acrylo)-nitrile; C456276:cucurbit(7)uril; D047028:Macrocyclic Compounds; D000099246:Cucurbit(n)urils; C031215:betadex