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Unusual effects in single molecule tautomerization: hemiporphycene
Victoriya Kim1, Lukasz Piatkowski2, Maria Pszona2
1Institute of Physical and Theoretical Chemistry and LISA+, University of Tübingen, Auf der Morgenstelle 18, D-72076 Tübingen, Germany. alfred.meixner@uni-tuebingen.de.
Physical Chemistry Chemical Physics : PCCP
|October 13, 2018
Summary
Single hemiporphycene molecules in PMMA films show slower tautomerization and shorter fluorescence lifetimes than bulk samples. This suggests multidimensional tautomerization and polymer interactions influence molecular behavior.
Area of Science:
- Photochemistry
- Polymer Science
- Spectroscopy
Background:
- Hemiporphycene, a porphyrin isomer, exists as two trans tautomers.
- Tautomerization occurs via double hydrogen transfer in solutions and polymer matrices.
- Confocal fluorescence microscopy allows single-molecule analysis.
Purpose of the Study:
- To monitor tautomerization in single hemiporphycene molecules within a PMMA film.
- To investigate the influence of the polymer environment on molecular dynamics.
- To compare single-molecule behavior with bulk ensemble studies.
Main Methods:
- Confocal fluorescence microscopy was used to study single hemiporphycene molecules.
- Spectral and temporal evolution of fluorescence spectra were monitored.
- Ensemble studies on bulk PMMA films were performed for comparison.
Main Results:
- Single-molecule studies revealed slower tautomerization rates for some molecules.
- Fluorescence lifetimes of single molecules were significantly shorter than bulk measurements.
- Observed effects were attributed to multidimensional tautomerization and polymer relaxation coupling.
Conclusions:
- The polymer matrix significantly influences hemiporphycene tautomerization dynamics.
- Environment-induced molecular distortion in thin films affects excited-state dynamics.
- Single-molecule spectroscopy provides insights into molecular behavior not observable in bulk studies.
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