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Ultrafast excited-state proton transfer from hydroxycoumarin-dipicolinium cyanine dyes

Paper ID Volume ID Publish Year Pages File Format Full-Text
26882 43984 2013 9 PDF Available
Title
Ultrafast excited-state proton transfer from hydroxycoumarin-dipicolinium cyanine dyes
Abstract

The photoprotolytic properties of a recently synthesized photoacid, hydroxycoumarin-dipicolinium salt (HCD) were studied by means of time-resolved emission techniques. We found that HCD is a super-photoacid with pKa*<−2 and with an excited-state proton transfer to water with a rate constant of kPT=1.4×1011 s−1kPT=1.4×1011 s−1. We also found that HCD undergoes ESPT in a large number of protic solvents. The kinetic isotope effect is about two for water, methanol and ethanol.

► We show a process of ESPT from HCD to different solvents upon photo-excitation. ► In water, the ESPT rate is high and the rate constant is ∼1.4 × 1011 s−1. ► We show ESPT processes in linear alcohols at a high rate, exceeding 3 × 1010 s−1. ► The kinetic isotope effect (KIE) is significant in water, methanol and ethanol.

Keywords
Excited-state proton transfer; Photoacid; Near infrared cyanine dye; Geminate recombination; Ultrafast phenomena; Laser induced processes
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Ultrafast excited-state proton transfer from hydroxycoumarin-dipicolinium cyanine dyes
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Publisher
Database: Elsevier - ScienceDirect
Journal: Journal of Photochemistry and Photobiology A: Chemistry - Volume 254, 15 February 2013, Pages 45–53
Authors
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Subjects
Physical Sciences and Engineering Chemical Engineering Bioengineering
Get Full-Text Now
Don't Miss Today's Special Offer
Price was $35.95
You save - $31
Price after discount Only $4.95
100% Money Back Guarantee
Full-text PDF Download
Online Support
Any Questions? feel free to contact us