title: Inclusion complexes between amphiphilic phenyleneethynylene fluorophores and cyclodextrins in aqueous media.
abstract: Binding events of cyclodextrins (CyD's) in aqueous media are important for designing and explaining the host-guest chemistry applied in sensing and controlled release systems. A water-soluble tricationic compound (3N(+)) with three branches of phenyleneethynylene fluorescent moieties and its related amphiphilic compounds (3C(-), N(0)N(+), N(+), and 2N(+)) are employed as molecular probes in the systematic characterization of the supramolecular interactions with CyD's (α, β, and γ). The strong fluorescence enhancement, combined with induced circular dichroism (CD) signals and (1)H NMR data, is evidence of 1:1 static inclusion complexes of 3N(+)/γ-CyD and 2N(+)/γ-CyD. 3N(+) presents a structural design which can form inclusion complexation with γ-CyD with one of the highest binding constants of 3.0 × 10(4). The relatively moderate fluorescence enhancement, shift of (1)H NMR signals, and weak induced CD signals indicate fast exchange complexation of β-CyD with the amphiphilic guest molecules. The interaction with α-CyD is perceived only for N(0)N(+), the only nonbranched fluorescent guest model, via its strong fluorescence enhancement. However, the lack of (1)H NMR signal splitting and the lack of induced CD signals suggest the noninclusion mode of binding between N(0)N(+) and α-CyD.
authors.affiliation: Department of Chemistry, Faculty of Science, Chulalongkorn University, Bangkok 10330, Thailand.
authors.forename: Warathip
authors.initials: W
authors.lastname: Siripornnoppakhun
authors.forename: Nakorn
authors.initials: N
authors.lastname: Niamnont
authors.forename: Akachai
authors.initials: A
authors.lastname: Krumsri
authors.forename: Gamolwan
authors.initials: G
authors.lastname: Tumcharern
authors.forename: Tirayut
authors.initials: T
authors.lastname: Vilaivan
authors.forename: Paitoon
authors.initials: P
authors.lastname: Rashatasakhon
authors.forename: S
authors.initials: S
authors.lastname: Thayumanavan
authors.forename: Mongkol
authors.initials: M
authors.lastname: Sukwattanasinitt
mesh_terms: D000480:Alkynes / Q000737:chemistry*; D002942:Circular Dichroism; D003505:Cyclodextrins / Q000737:chemistry*; D004987:Ethers / Q000737:chemistry*; D005456:Fluorescent Dyes / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D015335:Molecular Probes / Q000737:chemistry; D015394:Molecular Structure; D011522:Protons; D013501:Surface-Active Agents / Q000737:chemistry*; D014867:Water / Q000737:chemistry
chemical_list: D000480:Alkynes; D003505:Cyclodextrins; D004987:Ethers; D005456:Fluorescent Dyes; D015335:Molecular Probes; D011522:Protons; D013501:Surface-Active Agents; C436384:phenyleneethynylene; D014867:Water