Time-Resolved Resonance Raman and Density Functional Theory Investigation of the Aryl Azo Dimmer Formation

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Time-Resolved Resonance Raman and Density
Functional Theory Investigation of the Aryl Azo
Dimmer Formation
By Xue Jiadan Department of Chemistry The
University of Hong Kong
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Photochemistry of arylazide
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Different reaction pathways to form the azo
dimmer compounds
2-Fluorenyl azide
?
Meta-nitrophenyl azide Para-acetylphenyl azide
Azo dimmer compound
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Time-resolved resonance Raman detection of the
azo dimmer compound

• 341.5 nm TR3 spectra after 266 nm
• photolysis of m-nitrophenyl azide
• in 50MeCN 50H2O

341.5 nm TR3 spectra after 266 nm photolysis of
p-acetylphenyl azide in 50MeCN 50H2O
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Optimized geometry obtained by DFT calculation
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Vibrational frequencies obtained by DFT
calculation
Comparison of DFT calculation results and
experimental Raman spectra Azo dimmer formed from
m-nitrophenyl nitrene (left), and p-acetylphenyl
nitrene (right)
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Different reaction pathways to form the azo
dimmer compounds
2-Fluorenyl azide
Meta-nitrophenyl azide Para-acetylphenyl azide
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The second reaction pathway to form the azo
dimmer compoundTime-resolved Resonance Raman
spectra of different concentrations of
2-fluorneyl azide
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The second reaction pathway to form the azo
dimmer compoundThe nitrenium ion reaction with
the azide precursor
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The second reaction pathway to form the azo
dimmer compoundThree species produced during the
reation
Nitrenium Ion J.Am.Chem.Soc.2001,123,2645-2649
Need to be found by calculation
Azo dimmer confirmed by comparison of DFT
calculation result and experiment Raman spectrum
Raman spectra of three species
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Proposed possible reaction pathwayCalculating
Now!
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Thanks!!

• HKUHPCPOWER Cluster provide us a fast and
  convenient way to carry the Density Functional
  Theory calculation for the examined arylazide
  compounds in our research. This helps to give
  information of structure and bonding properties
  of key chemical reaction intermediates and lead
  to an improved understanding of mechanisms for
  azo dimmer and other kinds of compounds.

The End