Adsorption and emission enhancement behavior of 4,4′-bipyridine on dispersed montmorillonite nano-sheets under aqueous conditions

• Published in: Tetrahedron letters 2018-06, Vol.59 (25), p.2459-2462
• Main Authors: Nakazato, Ryosuke, Shimada, Tetsuya, Ohtani, Yuta, Ishida, Tamao, Takagi, Shinsuke
• Format: Article
• Language: English
• Subjects: Bipyridine; Clay nano-sheet; Montmorillonite; Protonation; Surface-Fixation Induced Emission (S-FIE)
• ISSN: 0040-4039; 1873-3581
• DOI: 10.1016/j.tetlet.2018.05.036

[Display omitted] •4,4′-Bipyridine (BPy) was adsorbed on an exfoliated montmorillonite nanosheet (MtNS).•BPy exhibited a relatively large red shift by 30 nm in the absorption spectrum.•BPy showed significant emission enhancement in the fluorescence spectrum.•A wide variety of molecules could be used as a guest of MtNS host material. The adsorption and photochemical behavior of 4,4′-bipyridine (BPy) on an exfoliated single montmorillonite nano-sheet (MtNS) was investigated in water. Under the appropriate conditions, BPy was adsorbed on the MtNS as a monomer state. BPy exhibited a relatively large red shift by 30 nm in the absorption spectrum, and showed significant emission enhancement in the fluorescence spectrum, contrary to the non-fluorescent property of BPy in water without MtNS. From the investigation using protonated BPy (BPyH22+) under acidic conditions, it was turned out that BPy was adsorbed as BPyH22+ on MtNS even under neutral conditions. From the analysis based on the Langmuir adsorption isotherm, the saturated adsorption amount of BPy on MtNS was calculated to be 3.2 × 10−2 molecule nm−2.