RotaxaneEncapsulation Enhances the Stability of an Azo Dye, in Solution and when Bonded to Cellulose

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Rotaxane-Encapsulation Enhances the Stability of
an Azo Dye, in Solution and when Bonded to
Cellulose.
Michael R. Craig, Michael G. Hutchings, Tim D. W.
Claridge and Harry L. Anderson.
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• Introduction.
• The reactive ? system of an azo dye can be
  stabilised by encapsulating it inside the cavity
  of a rotaxane macrocycle.
• The rotaxane is hoped to enhance stability
  towards reductive bleaching, oxidative bleaching
  and photo-bleaching.
• This may have applications in areas where
  chromophore degradation needs to be prevented.

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• The paper addresses two questions
• Does encapsulation improve the longevity of the
  azo chromophore?
• Does encapsulation detrimentally prevent the dye
  from binding to surfaces?

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Synthesis of Chlorotriazine-functionalised Azo
Dye Rotaxane.


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Attachment of Rotaxane to Cellulose Surface.

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Space Filling Model of Rotaxane.
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Graph to Show Reactivity of Rotaxane and Free Dye
Towards Reductive Bleaching.
1 Rotaxane
3 Free Dye
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Conclusion

• Encapsulation of the azo dye rotaxane
  dramatically
• increases stability towards bleaching with sodium
  
• dithionite, illustrated below.

• Encapsulation does not prevent it from being
  covalently
• attached to cotton cloth (cellulose).