1. Paper Presentation
3rd Feb 2012
Rijeesh K

2. Photo induced Memory Effect in a Redox Controllable Bistable Mechanical Molecular Switch
Tommaso Avellini, Hao Li, Ali Coskun, Gokhan Barin, Ali Trabolsi, Ashish N. Basuray,Sanjeev K. Dey, Alberto Credi,* Serena Silvi, J. Fraser Stoddart,* and Margherita Venturi
Angew. Chem. 2012, 124, 1 – Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim

3. Rotaxane:

4. Lifetime of Metastable state:
Chem. Eur. J. 2011, 17, 6076 – 6087
Angew. Chem. Int. Ed. 2011, 50, 9866 –9870

5. Photo induced Memory Effect in a Redox Controllable Bistable Mechanical Molecular Switch

6. Photo induced Memory Effect in a Redox Controllable Bistable Mechanical Molecular Switch
oxidation with up to 1 equiv of Fe(ClO4)3 to obtain trans-15+
reduction with 1 equiv of Me10Fc to obtain cis-14+

7. Photo induced Memory Effect in a Redox Controllable Bistable Mechanical Molecular Switch
Changes in the absorption spectrum observed in MeCN at 295 K for a 19 mm solution of trans-14+ (black trace) resulting from the following sequence of operations:
a) oxidation with up to 1 equiv of Fe(ClO4)3 to obtain trans-15+(blue trace).
b) exhaustive irradiation at 365 nm to obtain cis-15+ (red trace).
c) reduction with 1 equiv of Me10Fc to obtain cis-14+ (green trace).
d) Equilibration in the dark to obtain trans-14+(grey trace).

8. Photo induced Memory Effect in a Redox Controllable Bistable Mechanical Molecular Switch

9. Photo induced Memory Effect in a Redox Controllable Bistable Mechanical Molecular Switch

10. Photo induced Memory Effect in a Redox Controllable Bistable Mechanical Molecular Switch
Synthetic procedures :

11. Photo induced Memory Effect in a Redox Controllable Bistable Mechanical Molecular Switch
Synthetic procedures :

12. Photo induced Memory Effect in a Redox Controllable Bistable Mechanical Molecular Switch
Synthetic procedures :

13. Photo induced Memory Effect in a Redox Controllable Bistable Mechanical Molecular Switch
Synthetic procedures :

14. Synthetic procedures :
Photo induced Memory Effect in a Redox Controllable Bistable Mechanical Molecular Switch
Synthetic procedures :

15. Photo induced Memory Effect in a Redox Controllable Bistable Mechanical Molecular Switch

16. Photo induced Memory Effect in a Redox Controllable Bistable Mechanical Molecular Switch
Conclusion:
A rotaxane can operate as a bistable memory element under kinetic control. The data can be written on the rotaxane by an oxidation stimulus, and locked by UV light irradiation. After the writing session, the oxidized species can be reduced back to the original form without losing the written data for a remarkably longer time. Light irradiation, not only locks the data previously recorded by oxidation, but also protects the no oxidized rotaxanes from accidental writing.

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18. THANK YOU