Effect of Hydrogen Bonding on Ultrafast Intersystem Crossing in 7-Diethylaminothiocoumarin DOI
Abhijit Dutta, Suman Bhowmik, Sujit Kumar Ghosh

et al.

The Journal of Physical Chemistry A, Journal Year: 2025, Volume and Issue: unknown

Published: May 13, 2025

Thiocarbonyls exhibit unique photophysical properties, characterized by rapid intersystem crossing (ISC) due to favorable singlet-triplet energetics and enhanced spin-orbit coupling. However, the role of hydrogen bonding in modulating ISC remains underexplored. This study investigates effect solvent-solute on dynamics 7-(diethylamino)-4-methyl-2-sulfanylidene-2H-chromen-2-one (thiocoumarin 1, TC1) using steady-state time-resolved spectroscopy, complemented theoretical calculations. Experimental data reveal that methanol, leads increased fluorescence quantum yield, prolonged singlet-state lifetime, reduced triplet yield compared aprotic acetonitrile. Time-resolved spectroscopy identifies an additional long-lived emissive singlet state attributed a hydrogen-bonded state, which slows ISC. Theoretical calculations demonstrate alters electronic structure constrains along key nuclear coordinates, including C═S bond vibration dihedral angles, leading decreased formation. These findings provide mechanistic insights into hydrogen-bonding-mediated control thiocoumarins, with implications for designing functional materials tunable properties.

Language: Английский

Effect of Hydrogen Bonding on Ultrafast Intersystem Crossing in 7-Diethylaminothiocoumarin DOI
Abhijit Dutta, Suman Bhowmik, Sujit Kumar Ghosh

et al.

The Journal of Physical Chemistry A, Journal Year: 2025, Volume and Issue: unknown

Published: May 13, 2025

Thiocarbonyls exhibit unique photophysical properties, characterized by rapid intersystem crossing (ISC) due to favorable singlet-triplet energetics and enhanced spin-orbit coupling. However, the role of hydrogen bonding in modulating ISC remains underexplored. This study investigates effect solvent-solute on dynamics 7-(diethylamino)-4-methyl-2-sulfanylidene-2H-chromen-2-one (thiocoumarin 1, TC1) using steady-state time-resolved spectroscopy, complemented theoretical calculations. Experimental data reveal that methanol, leads increased fluorescence quantum yield, prolonged singlet-state lifetime, reduced triplet yield compared aprotic acetonitrile. Time-resolved spectroscopy identifies an additional long-lived emissive singlet state attributed a hydrogen-bonded state, which slows ISC. Theoretical calculations demonstrate alters electronic structure constrains along key nuclear coordinates, including C═S bond vibration dihedral angles, leading decreased formation. These findings provide mechanistic insights into hydrogen-bonding-mediated control thiocoumarins, with implications for designing functional materials tunable properties.

Language: Английский

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