title: Molecular pockets derived from cholic acid as chemosensors for metal ions.
abstract: Molecular pockets in the form of a tripod made of cholic acid were found to be able to solubilize pyrene in polar media as a result of the facial amphiphilicity of bile acids. The trimer containing 1,2,3-triazole groups can complex with heavy metal ions, as clearly shown by electron paramagnetic resonance spectroscopy. Both the metal cation and the pyrene molecule can be brought close together in the cavity formed by the cholic acid trimer, resulting in significantly improved efficiency for fluorescence quenching of pyrene. The decrease of fluorescence intensity can be used for the detection of heavy metal ions, and the detection limit is about 1 microM in water, suggesting the usefulness of such molecules as chemosensors for such metal ions. A different trimer without the coordinating triazole groups is shown to shield pyrene away from metal ions, causing a much reduced fluorescence quenching.
authors.affiliation: Département de Chimie, Université de Montréal, C. P. 6128, Succursale Centre-Ville, Montréal, QC, H3C 3J7, Canada.
authors.forename: Jiawei
authors.initials: J
authors.lastname: Zhang
authors.forename: Juntao
authors.initials: J
authors.lastname: Luo
authors.forename: X X
authors.initials: XX
authors.lastname: Zhu
authors.forename: Matthias J N
authors.initials: MJ
authors.lastname: Junk
authors.forename: Dariush
authors.initials: D
authors.lastname: Hinderberger
mesh_terms: D002623:Chemistry Techniques, Analytical / Q000379:methods*; D019826:Cholic Acid / Q000737:chemistry*; D003300:Copper / Q000737:chemistry; D005456:Fluorescent Dyes / Q000737:chemistry*; D057927:Hydrophobic and Hydrophilic Interactions; D007477:Ions / Q000032:analysis; D019216:Metals, Heavy / Q000032:analysis*; D011721:Pyrenes / Q000737:chemistry*; D012996:Solutions; D013499:Surface Properties; D014867:Water / Q000737:chemistry
chemical_list: D005456:Fluorescent Dyes; D007477:Ions; D019216:Metals, Heavy; D011721:Pyrenes; D012996:Solutions; D014867:Water; D003300:Copper; C030984:pyrene; D019826:Cholic Acid