Ultrafast excited-state proton transfer to the solvent occurs on a hundred-femtosecond time-scale

Ron Simkovitch; Naama Karton-Lifshin; Shay Shomer; Doron Shabat; Dan Huppert

doi:10.1021/jp4014724

Ultrafast excited-state proton transfer to the solvent occurs on a hundred-femtosecond time-scale

Ron Simkovitch, Naama Karton-Lifshin, Shay Shomer, Doron Shabat, Dan Huppert

School of Chemistry

Tel Aviv University

Research output: Contribution to journal › Article › peer-review

Abstract

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, k_PT ≈ 1 × 10 ¹³ s^-1, the fastest rate reported up to now. On the basis of the Förster-cycle, the pK_a* 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.

Original language	English
Pages (from-to)	3405-3413
Number of pages	9
Journal	Journal of Physical Chemistry A
Volume	117
Issue number	16
DOIs	https://doi.org/10.1021/jp4014724
State	Published - 25 Apr 2013

All Science Journal Classification (ASJC) codes

Physical and Theoretical Chemistry

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10.1021/jp4014724

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title = "Ultrafast excited-state proton transfer to the solvent occurs on a hundred-femtosecond time-scale",

abstract = "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 F{\"o}rster-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.",

author = "Ron Simkovitch and Naama Karton-Lifshin and Shay Shomer and Doron Shabat and Dan Huppert",

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doi = "10.1021/jp4014724",

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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.

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U2 - 10.1021/jp4014724

DO - 10.1021/jp4014724

M3 - مقالة

C2 - 23550613

SN - 1089-5639

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SP - 3405

EP - 3413

JO - Journal of Physical Chemistry A

JF - Journal of Physical Chemistry A

IS - 16

ER -

Ultrafast excited-state proton transfer to the solvent occurs on a hundred-femtosecond time-scale

Abstract

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