Interesting Solvatochromogenic Behaviors of 8Aminoquinoline Derivative

1
Interesting Solvatochromogenic Behaviors of
8-Aminoquinoline Derivative

• Young-Hee Kim, Jin-Soo Yuk, and Suk-Kyu Chang
• Department of Chemistry, Chung-Ang University

2
Introduction
3
Synthesis of 8-Aminoquinoline Benzothiazole
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UV Spectra of 3 with Various Metal ions
3 and 3 with other metal ions
Absorbance
3 Hg2
Wavelength (nm)
Figure 1. UV spectra of 3 in Dioxane-H2O (95 5,
v/v) with various metal ions. 3 1 ? 10-5 M
M2 1 ? 10-3 M
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Fluorescence Spectra of 3 with Various Metal ions
3 and 3 with other metal ions
3 Hg2
Relative Intensity
3 Cu2
Wavelength (nm)
Figure 2. Fluorescence spectra of 3 in
Dioxane-H2O (91, v/v) with various metal ions.
3 1 ? 10-5 M M2 1 ? 10-3 M
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Fluorescence Intensity ratio (I/Io) of 3 for
Metal ions in Various Solvent Systema

• I and Io denote fluorescence intensity of 3 (?ex
  310 nm) in the presence of 100 equiv metal ions
  and in the absence of metal ions, respectively.
  3 1.0 x 10-5, M2 1.0 x 10-3

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1H NMR Spectral Changes of 3 by the Addition of
Hg2 ions
Figure 3. 1H NMR spectral changes of 3 by the
addition of Hg(ClO4)2 at 300 MHz in CD3CN. 3
6.7 x 10-3 M.
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Solvent Polarity of 3 in Aprotic Solvent-H2O
Mixtures
Increasing H2O
Relative Intensity
Df
Wavelength (nm)
Figure 6. Fluorescence emission spectra of 3 in
1,4-dioxane (10-5 M) to which H2O was added.
Figure 7. Effects of solvents composition on the
fluorescence emission maximum of 3
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Solvent Polarity of 3 in Various Solvents
Dn (10-3cm-1)
?em
Figure 4. Plot of fluorescence emission maximum
?em against Dimroths ET(30) for 3 in tested
solvents (From the left, n-Hexane, Ether,
Acetone, THF, Dioxane, MeOH, EtOH, H2O)
Figure 5. Stokes shift of 3 in various solvents
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Conclusion

• Newly synthesized 8-Aminoquinoline benzothiazole
  acts as a highly selective Hg2 ion probe.
• ? A Hypsochromic Shift by Hg2 ion Complexation
  
• ? A Large Ka value (2.9 x 104 M-1) and a Lower
  Detection limit (6.0 X 10-5 M)
• ? Quantitative 12 complexation with Hg2 ion
  from Jobs plot
• Solvatochromogenic behaviors which can be applied
  for a solvent polarity probe
• ? The emission maximum ?em shifts from 489 nm in
  n-hexane to 598 nm in methanol
• The sensibility of ?em with small amount of water
  can be also applied for the detection of water in
  polar organic solvents.