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Photoluminescence emission enhancement and coordination-driven isomer-locking effects of Cr(III) on azobenzene-bearing tweezer anchored to binaphthdiaza-crown macrocycles

Ghanbari, B ; Sharif University of Technology | 2018

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  1. Type of Document: Article
  2. DOI: 10.1016/j.jlumin.2018.04.065
  3. Publisher: Elsevier B.V , 2018
  4. Abstract:
  5. In this report, the synthesis of a new bi-macrocycle tweezer linked through an azobenzene moiety, L was undertaken. The characterization of the tweezer was accomplished by employing IR, 1H and 13C NMR, UV–vis, fluorescence spectroscopy and CHN microanalysis while the UV–visible spectroscopy illustrated a trans ⇆ cis photo-isomerization for L. According to our preliminary fluorescence observations, a metal-ion chemosensing behavior was established for trans-L isomer towards Cr(III) ion among the library metal ions. The quenching of the respective trans ⇆ cis isomerization in the presence of Cr(III) ion suggested the preference of a strong interaction between Cr(III) ion with L, leading to isomer-locking of the trans-L isomer. Since the Job plots for L in the presence of Cr(III) metal ion suggested a 1:2 ratios for the interaction of Cr(III) with L, an electronic effect of Cr(III) ion with the phenolic groups on L was suggested as the main factor for the observed isomer-locking process in trans-L. The binding constant and the detection limit for Cr(III) ion by L were also assessed as 1.55 × 108 M−1 and 10−8 M, respectively, suggesting L as a new chemosensor for Cr(III) metal ion. © 2018 Elsevier B.V
  6. Keywords:
  7. Azobenzene ; Fluorescence ; Isomer-locking macrocycle ; Naphthdiaza-crown ; Tweezer ; Azobenzene ; Fluorescence spectroscopy ; Isomerization ; Isomers ; Locks (fasteners) ; Metal ions ; Metals ; Coordination-driven ; Electronic effects ; Macrocycles ; Photoluminescence emission ; Strong interaction ; Visible spectroscopy ; Chromium compounds
  8. Source: Journal of Luminescence ; Volume 201 , 2018 , Pages 329-337 ; 00222313 (ISSN)
  9. URL: https://www.sciencedirect.com/science/article/pii/S0022231317319592