Dataset Information

2 + 2 Can Make Nearly a Thousand! Comparison of Di- and Tetra-Meso-Alkyl-Substituted Porphycenes.

ABSTRACT: Two porphycenes, substituted at the meso positions with two and four methyl groups, respectively, reveal similar absorption spectra, but their photophysical properties are completely different. 9,20-dimethylporphycene emits fluorescence with about 20% quantum yield, independent of the solvent. In contrast, fluorescence of 9,10,19,20-tetramethylporphycene is extremely weak in nonviscous solvents, but it can be recovered by placing the chromophore in a rigid environment. We propose a model that explains these differences, based on calculations and structural analogies with other extremely weakly emitting derivatives, dibenzo[cde,mno]porphycenes. The efficient S1 deactivation involves delocalization of two inner cavity protons coupled with proton translocation toward a high-energy cis tautomer. The latter process leads to distortion from planarity. The probability of deactivation increases with the strength of the intramolecular NH···N hydrogen bonds. The model also explains the observation of biexponential fluorescence decay in weakly emitting porphycenes. It can be extended to other derivatives, in particular, the asymmetrically substituted ones. We also point to the possibility of using specific porphycenes as viscosity sensors, in particular, when working in single molecule regime.

SUBMITTER: Kijak M

PROVIDER: S-EPMC7590974 | biostudies-literature | 2020 Jun

REPOSITORIES: biostudies-literature

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2 + 2 Can Make Nearly a Thousand! Comparison of Di- and Tetra-<i>Meso</i>-Alkyl-Substituted Porphycenes.

Kijak Michał M Nawara Krzysztof K Listkowski Arkadiusz A Masiera Natalia N Buczyńska Joanna J Urbańska Natalia N Orzanowska Grażyna G Pietraszkiewicz Marek M Waluk Jacek J

The journal of physical chemistry. A 20200528 23

Two porphycenes, substituted at the <i>meso</i> positions with two and four methyl groups, respectively, reveal similar absorption spectra, but their photophysical properties are completely different. 9,20-dimethylporphycene emits fluorescence with about 20% quantum yield, independent of the solvent. In contrast, fluorescence of 9,10,19,20-tetramethylporphycene is extremely weak in nonviscous solvents, but it can be recovered by placing the chromophore in a rigid environment. We propose a model ...[more]

PMID: 32423205

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Dataset Information

2 + 2 Can Make Nearly a Thousand! Comparison of Di- and Tetra-Meso-Alkyl-Substituted Porphycenes.

Publications

2 + 2 Can Make Nearly a Thousand! Comparison of Di- and Tetra-<i>Meso</i>-Alkyl-Substituted Porphycenes.

Similar Datasets

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