Coherent intermolecular proton transfer in the acid-base reaction of excited state pyranine

Cited 12 time in webofscience Cited 0 time in scopus
  • Hit : 249
  • Download : 0
Detailed molecular dynamics simulations of an acid-base reaction have been the subject of extensive investigations. Here we report the excited state proton transfer dynamics of pyranine (8-hydroxypyrene1,3,6- trisulfonic acid, HPTS) in acetate buffer by time-resolved fluorescence (TF) and quantum mechanical/ effective fragment potential molecular dynamics (QM/ EFP-MD) simulations. High time resolution in TF and TF spectra measurements allows the acquisition of accurate reaction kinetics. Upon the photoexcitation of HPTS, the proton (deuterium) is transferred coherently to acetate in 60 fs (80 fs) for a contact pair of HPTS (DPTS) and acetate by a hydrogen bond, which comprises approximately 28% of the population. ESPT proceeds slowly on a picosecond time scale for the remaining HPTS as reported previously. Coherent wave packet motions of the reactant (acid) and the product (conjugate base) enable the acquisition of the vibrational spectra of excited states via TF (VETF). A comparison of the VETFs of the reactant and the product and the calculation of the Huang-Rhys factors (vibrational reorganization energies) identify the vibrational modes that actively participate in the coherent proton transfer. In particular, the 246 cm(-1) vibrational mode, which consists of in-plane skeletal stretching motion, promotes the ESPT by transferring the donor oxygen towards the acceptor oxygen in acetate. QM/EFP MD simulations corroborate the experiment and provide molecular details of the ESPT.
Publisher
ROYAL SOC CHEMISTRY
Issue Date
2017-07
Language
English
Article Type
Article
Keywords

STIMULATED RAMAN-SPECTROSCOPY; DENSITY-FUNCTIONAL THEORY; REAL-TIME OBSERVATION; SPIN-FLIP APPROACH; TRANSFER DYNAMICS; ORGANIC-PHOTOCHEMISTRY; GEMINATE RECOMBINATION; AQUEOUS-SOLUTION; PH JUMP; WATER

Citation

PHYSICAL CHEMISTRY CHEMICAL PHYSICS, v.19, no.28, pp.18243 - 18251

ISSN
1463-9076
DOI
10.1039/c7cp01944k
URI
http://hdl.handle.net/10203/227223
Appears in Collection
CH-Journal Papers(저널논문)
Files in This Item
There are no files associated with this item.
This item is cited by other documents in WoS
⊙ Detail Information in WoSⓡ Click to see webofscience_button
⊙ Cited 12 items in WoS Click to see citing articles in records_button

qr_code

  • mendeley

    citeulike


rss_1.0 rss_2.0 atom_1.0