Ferrocene-substituted nitrogen-rich ring systems as multichannel molecular chemosensors for anions in aqueous environment.
The synthesis, electrochemical, optical, and anion sensing properties of ferrocene-fused imidazole dyads are presented. Ferrocene-benzobisimidazole dyad 1 behaves as a highly selective redox, chromogenic and fluorescent chemosensor molecule for AcO(-) anion in DMSO/H(2)O: the oxidation redox peak is cathodically shifted (DeltaE(1/2) = -170 mV), perturbation of the UV-vis spectrum, and the emission band is both red-shifted (Delta lambda = 13 nm) and increased (Chelation Enhanced Fluorescence, CHEF = 133) upon complexation with this anion. The related ferrocene-bisbenzimidazole dyad 2 has shown the ability for sensing both H(2)PO(4)(-) and HP(2)O(7)(3-) anions in the same medium. Upon complexation, it also displays a cathodic shift of the redox potential (DeltaE(1/2) = -90 to 80 mV), as well as a clear perturbation of the UV-vis spectrum and an increase in the intensity of the emission band (CHEF = 97-37). However, such magnitudes are smaller than those exhibited by 1. (1)H NMR studies have been carried out to obtain information about the molecular sites which are involved in the binding process.
Zapata
Fabiola
F
Departamento de Química Orgánica, Facultad de Química, Campus de Espinardo, Universidad de Murcia, E-30100 Murcia, Spain.
Caballero
Antonio
A
Tárraga
Alberto
A
Molina
Pedro
P
D000838:Anions / Q000737:chemistry*; D004563:Electrochemistry; D005296:Ferrous Compounds / Q000737:chemistry*; D005456:Fluorescent Dyes / Q000737:chemistry*; D007093:Imidazoles / Q000138:chemical synthesis / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D000075163:Metallocenes; D008958:Models, Molecular; D009584:Nitrogen / Q000737:chemistry*; D010084:Oxidation-Reduction; D013050:Spectrometry, Fluorescence; D013056:Spectrophotometry, Ultraviolet; D014867:Water
D000838:Anions; D005296:Ferrous Compounds; D005456:Fluorescent Dyes; D007093:Imidazoles; D000075163:Metallocenes; D014867:Water; D009584:Nitrogen; C004998:ferrocene