TY - JOUR
T1 - Ultrafast excited-state proton transfer to the solvent occurs on a hundred-femtosecond time-scale
AU - Simkovitch, Ron
AU - Karton-Lifshin, Naama
AU - Shomer, Shay
AU - Shabat, Doron
AU - Huppert, Dan
PY - 2013/4/25
Y1 - 2013/4/25
N2 - Steady-state and ultrafast time-resolved techniques were used to study a newly synthesized photoacid, phenol-carboxyether dipicolinium cyanine dye, QCy9. We found that the excited-state proton transfer (ESPT) to water occurs at the remarkably short time of about 100 fs, kPT ≈ 1 × 10 13 s-1, the fastest rate reported up to now. On the basis of the Förster-cycle, the pKa* value is estimated to be -8.5 ± 0.4. In previous studies, we reported the photoacidity of another superphotoacid, the QCy7 for which we found an ESPT rate constant of ∼1.25 × 1012 s-1, one-eighth that of the QCy9 compound. We found a kinetic isotope effect of the ESPT of about two.
AB - Steady-state and ultrafast time-resolved techniques were used to study a newly synthesized photoacid, phenol-carboxyether dipicolinium cyanine dye, QCy9. We found that the excited-state proton transfer (ESPT) to water occurs at the remarkably short time of about 100 fs, kPT ≈ 1 × 10 13 s-1, the fastest rate reported up to now. On the basis of the Förster-cycle, the pKa* value is estimated to be -8.5 ± 0.4. In previous studies, we reported the photoacidity of another superphotoacid, the QCy7 for which we found an ESPT rate constant of ∼1.25 × 1012 s-1, one-eighth that of the QCy9 compound. We found a kinetic isotope effect of the ESPT of about two.
UR - http://www.scopus.com/inward/record.url?scp=84876860844&partnerID=8YFLogxK
U2 - 10.1021/jp4014724
DO - 10.1021/jp4014724
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C2 - 23550613
AN - SCOPUS:84876860844
SN - 1089-5639
VL - 117
SP - 3405
EP - 3413
JO - Journal of Physical Chemistry A
JF - Journal of Physical Chemistry A
IS - 16
ER -