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Measurement of Ultrafast Vibrational Coherences in Polyatomic Radical Cations with Strong-Field Adiabatic Ionization
Published on: August 6, 2018
Site-selective bimodal absorption and emission of distonic radical cation
Sachiko Tojo1, Mamoru Fujitsuka, Tetsuro Majima
1The Institute of Scientific and Industrial Research (SANKEN), Osaka University Mihogaoka 8-1, Ibaraki, Osaka 567-0047, Japan.
The Journal of Organic Chemistry
|May 11, 2010
Summary
A novel dimeric radical cation, 1,1-bis(4-methoxyphenyl)ethylene dimer radical cation (DAE(2)(*+)), was synthesized. This molecule exhibits distinct radical and cation sites, with localized spin and charge, influencing its spectral and excited-state properties.
Area of Science:
- Organic Chemistry
- Photochemistry
- Spectroscopy
Background:
- Dimerization of radical cations can lead to unique electronic structures.
- Understanding charge and spin localization is crucial for molecular electronics.
Purpose of the Study:
- To synthesize and characterize a novel acyclic 1,4-distonic dimer radical cation.
- To investigate the electronic and photophysical properties of this dimer.
- To elucidate the interaction between radical and cation sites.
Main Methods:
- Solution-phase generation of the dimer radical cation.
- UV-Vis absorption spectroscopy.
- Site-selective excitation and emission spectroscopy at 77 K.
- Transient absorption measurements.
- Theoretical calculations.
Main Results:
- Successful generation of the 1,1-bis(4-methoxyphenyl)ethylene dimer radical cation (DAE(2)(*+)).
- DAE(2)(*+) exhibits bimodal absorption bands at 350 and 500 nm, indicating localized radical and cation sites.
- Excitation energy was observed to be localized on either the radical or cation site in the excited state.
- Ground and excited state interactions were analyzed.
Conclusions:
- DAE(2)(*+) possesses a unique 1,4-distonic structure with localized spin and charge.
- The dimer exhibits distinct spectral and photophysical behaviors due to site-specific electronic localization.
- Spectroscopic and computational data provide insights into radical-cation interactions.
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