Contacts:
Supervisor(s):
Prof. Giovanni Granucci
Title of the PhD project:
Photochemistry of molecular switches based on spiropyrans
Abstract of the PhD project:
Spiropyrans are a broad class of compounds whose use is widely found in materials science. Due to their photochromic characteristics, the spiropyrans can be used in a variety of applications, such as photoswitches, memory devices and biological imaging tools, attracting research interest towards their synthesis and characterization. Among the family of spiropyranic compounds, the 1′,3′-Dihydro-1′,3′,3′-trimethyl-6-nitrospiro[2H-1-benzopyran-2,2′-[2H]-indole] (nitroBIPS) deserves particular attention: as a matter of fact the presence of the nitro group at the 6-position of the benzopyran subunit shifts the equilibrium spiropyran-merocyanine toward the open form merocyanine. Furthermore the presence of the nitro group strongly enhances the quantum yield of intersystem crossing in the nitroBIPS. However, despite numerous experimental studies involving spiropyrans, the exact mechanism of the photoisomerization reaction has not been fully understood yet.
The main aim of this research project is to elucidate the photoisomerization mechanism of nitroBIPS and the role of triplet states in this process. Therefore I will investigate the photochemistry of nitroBIPS under several conditions: as a free molecule, in solution and under extremely high pressures. Besides I will simulate the phenomenon of the aggregation-induced (enhanced) emission (AIEE) in merocyanine J-type aggregates of nitroBIPS.
Publications:
• D. Frassi, G. Padula, and G. Granucci. “Photoisomerization of Spiropyran in Solution: A Surface Hopping Investigation”. In: The Journal of Physical Chemistry B 128.21 (2024), pp. 5246–5253. https://doi.org/10.1021/acs.jpcb.4c00778.
Oral communications at conferences:
• D. Frassi, G.Granucci. The interplay between nitro-substitutions and solvent effects in the photoisomerization of spiropyrans. Oral contribution at “CFF 2024, Chemistry for the Future” - International Conference, Jul 2024, Pisa, Italy
• D. Frassi, G.Granucci. Photoisomerization Dynamics of Spiropyrans. Oral contribution at “VIII Congresso nazionale della divisione di chimica teorica e computazionale della società chimica italiana” - Congress, Sep 2023, Scuola Normale Superiore, Pisa, Italy
• D. Frassi, G.Granucci. Photoisomerization Dynamics of Spiropyrans. Flash presentation at “Quantum Dynamics and Spectroscopy of Functional Molecular Materials and Biological Photosystems ” - Training school, Aug 2023, Les Houches, France
Poster communications at conferences:
• D. Frassi, G.Granucci. Photoisomerization Dynamics of Spiropyrans. “CFF 2023, Chemistry for the Future” - International Conference, Jun 2023, Pisa, Italy .
Other achievements:
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