1. Excited-State Dynamics of a DNA Duplex in a Deep Eutectic Solvent Probed by Femtosecond Time-Resolved IR Spectroscopy
- Author
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Kimberly de La Harpe, Yuyuan Zhang, Forrest R. Kohl, and Bern Kohler
- Subjects
Models, Molecular ,Aqueous solution ,Time Factors ,Spectrophotometry, Infrared ,Analytical chemistry ,Infrared spectroscopy ,02 engineering and technology ,DNA ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Excimer ,01 natural sciences ,0104 chemical sciences ,Deep eutectic solvent ,Solvent ,chemistry.chemical_compound ,chemistry ,Excited state ,Ionic liquid ,Solvents ,Nucleic Acid Conformation ,Quantum Theory ,Physical and Theoretical Chemistry ,0210 nano-technology ,Choline chloride - Abstract
To better understand how the solvent influences excited-state deactivation in DNA strands, femtosecond time-resolved IR (fs-TRIR) pump–probe measurements were performed on a d(AT)9·d(AT)9 duplex dissolved in a deep eutectic solvent (DES) made from choline chloride and ethylene glycol in a 1:2 mol ratio. This solvent, known as ethaline, is a member of a class of ionic liquids capable of solubilizing DNA with minimal disruption to its secondary structure. UV melting analysis reveals that the duplex studied here melts at 18 °C in ethaline compared to 50 °C in aqueous solution. Ethaline has an excellent transparency window that facilitates TRIR measurements in the double-bond stretching region. Transient spectra recorded in deuterated ethaline at room temperature indicate that photoinduced intrastrand charge transfer occurs from A to T, yielding the same exciplex state previously detected in aqueous solution. This state decays via charge recombination with a lifetime of 380 ± 10 ps compared to the 300 ± 10 ps...
- Published
- 2018