In search of excited-state proton transfer in the lumichrome dimer in the solid state: theoretical and experimental approach.

Authors:
Ewa Sikorska
Ewa Sikorska
Poznań University of Economics
Poland
Dr. Igor Khmelinskii, PhD, Prof. Agregado
Dr. Igor Khmelinskii, PhD, Prof. Agregado
University of the Algarve
PhD, Prof. Agregado
physcal chemistry; spectroscopy; climate science
Faro, Algarve | Portugal
Maciej Kubicki
Maciej Kubicki
Adam Mickiewicz University
Marcin Hoffmann
Marcin Hoffmann
A. Mickiewicz University
Jerzy Karolczak
Jerzy Karolczak
Adam Mickiewicz University
Poland

J Phys Chem A 2006 Apr;110(14):4638-48

Faculty of Commodity Science, Poznań University of Economics, al. Niepodleglości 10, 60-967 Poznań, Poland.

Quantum chemical density functional theory (DFT) calculations and spectral data were employed to investigate the possibility of the excited-state double proton transfer (ESDPT) in lumichrome crystals. The calculations in a lumichrome dimer predict a transfer of a proton in the first excited state, leading to a cation-anion pair. The presently reported X-ray structure of 1,3-dimethyllumichrome and its complex solid-state luminescence indicate that also in this molecule intermolecular hydrogen bonds might be involved in the photophysics. The long-wavelength emission in lumichrome crystals peaked at 530 nm is attributed to excited-state proton transfer, whereas a wider emission band in methylated lumichrome derivatives peaked at 560 nm is attributed to ions formed upon photoexcitation of the crystals.

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http://dx.doi.org/10.1021/jp060072yDOI Listing
April 2006
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