title: Cyclam-methylbenzimidazole: a selective OFF-ON fluorescent sensor for zinc.
abstract: The coordination properties and the photophysical response of a new cyclam fluorescent probe for Zn(II), [L1H: 1-(benzimidazol-2-ylmethyl]-1,4, 8,11-tetraazacyclotetradecane] toward Cu(II), Zn(II), and Cd(II) are reported. The stability constants of the corresponding complexes were determined by means of potentiometric measurements in aqueous solution. The fluorescence of L1H was quenched by the presence of Cu(II), and L1H behaves as an OFF-ON sensor for Zn(II) even in the presence of a wide range of biological divalent cations. Furthermore, on addition of successive amounts of Zn(II), the fluorescence emission of L1H increases linearly by a factor of 12. This can be correlated to the efficient Zn(II) binding of L1H and to the participation of all the amine functions in the metal coordination which prevents the photoinduced electron transfer (PET) effect and promotes a good chelation-enhanced fluorescence (CHEF) effect; this confers to the cyclam probe better sensing properties than the cyclen ionophore.
authors.affiliation: Groupe Chimie de Coordination, Institut de Chimie Moléculaire de Reims, Université Reims-Champagne-Ardenne, UMR 6229, C2POM, Bât. 18, BP 1039, 51687 Reims Cedex 2, France.
authors.forename: Abir
authors.initials: A
authors.lastname: El Majzoub
authors.forename: Cyril
authors.initials: C
authors.lastname: Cadiou
authors.forename: Isabelle
authors.initials: I
authors.lastname: Déchamps-Olivier
authors.forename: Bernard
authors.initials: B
authors.lastname: Tinant
authors.forename: Françoise
authors.initials: F
authors.lastname: Chuburu
mesh_terms: D001372:Aza Compounds / Q000737:chemistry*; D001562:Benzimidazoles / Q000737:chemistry*; D002623:Chemistry Techniques, Analytical / Q000295:instrumentation*; D005456:Fluorescent Dyes / Q000737:chemistry*; D006571:Heterocyclic Compounds / Q000737:chemistry*; D008958:Models, Molecular; D008968:Molecular Conformation; D055620:Optical Phenomena; D055668:Photochemical Processes; D011199:Potentiometry; D013050:Spectrometry, Fluorescence; D013816:Thermodynamics; D015032:Zinc / Q000032:analysis* / Q000737:chemistry
chemical_list: C560521:1-(benzimidazol-2-ylmethyl)-1,4, 8,11-tetraazacyclotetradecane; D001372:Aza Compounds; D001562:Benzimidazoles; D005456:Fluorescent Dyes; D006571:Heterocyclic Compounds; C024560:cyclam; D015032:Zinc