1
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Jang T, Lee S, Pang Y. Anomalous proton transfer of a photoacid HPTS in nonaqueous reverse micelles. Phys Chem Chem Phys 2024; 26:11283-11294. [PMID: 38456549 DOI: 10.1039/d3cp05710k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/09/2024]
Abstract
The proton transfer reaction is one of the fundamental chemical reactions where the reaction dynamics strongly depend on solvent properties such as acidity or basicity. A photoacid 8-hydroxypyrene-1,3,6-trisulfonic acid (HPTS) shows a sharp decrease of pKa (7.7 → 0.5) upon photoexcitation, and the excited-state proton transfer (ESPT) occurs with ultrafast time constants of 2.5 and 89 ps in bulk aqueous solution. However, the two-step proton transfers via the contact ion pair formation and the proton diffusion are strongly limited inside the nanopools of reverse micelles (RMs). The confinement in small RMs strongly impeded the proton transfer reactions. In this work, we report the ESPT of HPTS confined in methanol-in-oil RMs by steady-state and time-resolved electronic spectroscopy. Interestingly, HPTS shows substantial deprotonation in the excited state only in small RMs, while the ESPT of HPTS does not occur in bulk methanol solution due to the low basicity of aliphatic alcohols. The kinetic analysis of time-resolved fluorescence and transient absorption measurements will compare the proton transfer dynamics of HPTS in the water-in-oil and methanol-in-oil RMs. The ESPT of photoacids, especially in the nonaqueous RMs, can be crucial in understanding many important chemical reactions involving proton transfer in the confined environments of cells and membranes.
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Affiliation(s)
- Taehyung Jang
- Department of Chemistry, Gwangju Institute of Science and Technology, 123 Cheomdangwagi-ro, Buk-gu, Gwangju 61005, Republic of Korea.
| | - Sebok Lee
- Department of Chemistry, Gwangju Institute of Science and Technology, 123 Cheomdangwagi-ro, Buk-gu, Gwangju 61005, Republic of Korea.
| | - Yoonsoo Pang
- Department of Chemistry, Gwangju Institute of Science and Technology, 123 Cheomdangwagi-ro, Buk-gu, Gwangju 61005, Republic of Korea.
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2
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Wang JK, Wang CH, Wu CC, Chang KH, Wang CH, Liu YH, Chen CT, Chou PT. Hydrogen-Bonded Thiol Undergoes Unconventional Excited-State Intramolecular Proton-Transfer Reactions. J Am Chem Soc 2024; 146:3125-3135. [PMID: 38288596 PMCID: PMC10859960 DOI: 10.1021/jacs.3c10405] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2023] [Revised: 01/06/2024] [Accepted: 01/08/2024] [Indexed: 02/08/2024]
Abstract
The chapter on the thiol-related hydrogen bond (H-bond) and its excited-state intramolecular proton-transfer (ESIPT) reaction was recently opened where compound 4'-diethylamino-3-mercaptoflavone (3NTF) undergoes ESIPT in both cyclohexane solution and solid, giving a 710 nm tautomer emission with an anomalously large Stokes shift of 12,230 cm-1. Considering the thiol H-bond to be unconventional compared to the conventional Pauling-type -OH or -NH H-bond, it is thus essential and timely to probe its fundamental difference between their ESIPT. However, thiol-associated ESIPT tends to be nonemissive due to the dominant nπ* character of the tautomeric lowest excited state. Herein, based on the 3-mercaptoflavone scaffold and π-elongation concept, a new series of 4'-substituted-7-diethylamino-3-mercaptoflavones, NTFs, was designed and synthesized with varied H-bond strength and 690-720 nm tautomeric emission upon ultraviolet (UV) excitation in cyclohexane. The order of their H-bonding strength was experimentally determined to be N-NTF < O-NTF < H-NTF < F-NTF, while the rate of -SH ESIPT measured by fluorescence upconversion was F-NTF (398 fs)-1 < H-NTF (232 fs)-1 < O-NTF (123 fs)-1 < N-NTF (101 fs)-1 in toluene. Unexpectedly, the strongest H-bonded F-NTF gives the slowest ESIPT, which does not conform to the traditional ESIPT model. The results are rationalized by the trend of carbonyl oxygen basicity rather than -SH acidity. Namely, the thiol acidity relevant to the H-bond strength plays a minor role in the driving force of ESIPT. Instead, the proton-accepting strength governs ESIPT. That is to say, the noncanonical thiol H-bonding system undergoes an unconventional type of ESIPT.
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Affiliation(s)
- Jian-Kai Wang
- Department
of Chemistry, National Taiwan University, Taipei 10617, Taiwan, Republic of
China
| | - Chih-Hsing Wang
- Department
of Chemistry, National Taiwan University, Taipei 10617, Taiwan, Republic of
China
| | - Chi-Chi Wu
- Department
of Chemistry, National Taiwan University, Taipei 10617, Taiwan, Republic of
China
| | - Kai-Hsin Chang
- Department
of Chemistry, National Taiwan University, Taipei 10617, Taiwan, Republic of
China
| | - Chun-Hsiang Wang
- Department
of Chemistry, National Taiwan University, Taipei 10617, Taiwan, Republic of
China
| | - Yi-Hung Liu
- Department
of Chemistry, National Taiwan University, Taipei 10617, Taiwan, Republic of
China
| | - Chao-Tsen Chen
- Department
of Chemistry, National Taiwan University, Taipei 10617, Taiwan, Republic of
China
- Center
for Emerging Material and Advanced Devices, National Taiwan University, Taipei 10617, Taiwan, Republic of China
| | - Pi-Tai Chou
- Department
of Chemistry, National Taiwan University, Taipei 10617, Taiwan, Republic of
China
- Center
for Emerging Material and Advanced Devices, National Taiwan University, Taipei 10617, Taiwan, Republic of China
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3
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Bin Mohd Yusof MS, Song H, Debnath T, Lowe B, Yang M, Loh ZH. Ultrafast proton transfer of the aqueous phenol radical cation. Phys Chem Chem Phys 2022; 24:12236-12248. [PMID: 35579397 DOI: 10.1039/d2cp00505k] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Proton transfer (PT) reactions are fundamental to numerous chemical and biological processes. While sub-picosecond PT involving electronically excited states has been extensively studied, little is known about ultrafast PT triggered by photoionization. Here, we employ femtosecond optical pump-probe spectroscopy and quantum dynamics calculations to investigate the ultrafast proton transfer dynamics of the aqueous phenol radical cation (PhOH˙+). Analysis of the vibrational wave packet dynamics reveals unusually short dephasing times of 0.18 ± 0.02 ps and 0.16 ± 0.02 ps for the PhOH˙+ O-H wag and bend frequencies, respectively, suggestive of ultrafast PT occurring on the ∼0.1 ps timescale. The reduced potential energy surface obtained from ab initio calculations shows that PT is barrierless when it is coupled to the intermolecular hindered translation between PhOH˙+ and the proton-acceptor water molecule. Quantum dynamics calculations yield a lifetime of 193 fs for PhOH˙+, in good agreement with the experimental results and consistent with the PT reaction being mediated by the intermolecular O⋯O stretch. These results suggest that photoionization can be harnessed to produce photoacids that undergo ultrafast PT. In addition, they also show that PT can serve as an ultrafast deactivation channel for limiting the oxidative damage potential of radical cations.
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Affiliation(s)
- Muhammad Shafiq Bin Mohd Yusof
- Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, Singapore 637371, Singapore.
| | - Hongwei Song
- State Key Laboratory for Magnetic Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Sciences, Wuhan 430071, China
| | - Tushar Debnath
- Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, Singapore 637371, Singapore.
| | - Bethany Lowe
- Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, Singapore 637371, Singapore.
| | - Minghui Yang
- State Key Laboratory for Magnetic Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Sciences, Wuhan 430071, China.,Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology, Wuhan 430071, China
| | - Zhi-Heng Loh
- Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, Singapore 637371, Singapore.
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4
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Lee C, Seo K, Kim M, Joo T. Coherent internal conversion from high lying electronic states to S 1 in boron-dipyrromethene derivatives. Phys Chem Chem Phys 2021; 23:25200-25209. [PMID: 34730576 DOI: 10.1039/d1cp03513d] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Internal conversion is the first step after photoexcitation to high lying electronic states, and plays a central role in many photoinduced processes. In this report, we demonstrate a truly ultrafast internal conversion (IC) in large molecules by time-resolved fluorescence (TF). Following photoexcitation to the Sn (n ≥ 2) state, TF of the S1 state was recorded for two boron-dipyrromethene (BODIPY) derivatives in solution. IC to S1 takes place nearly instantaneously within 20 fs for both molecules. Abundant nuclear wave packet motions in the S1 state are manifest in the TF signals, which demonstrates that the IC in these BODIPY molecules is coherent with respect to most of the vibrational modes. Theoretical calculations assuming impulsive IC to S1 account for the wave packet dynamics accurately.
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Affiliation(s)
- Changmin Lee
- Department of Chemistry, Pohang University of Science and Technology (POSTECH), Pohang, 37673, South Korea.
| | - Kiho Seo
- Department of Chemistry, Pohang University of Science and Technology (POSTECH), Pohang, 37673, South Korea.
| | - Munnyon Kim
- Department of Chemistry, Pohang University of Science and Technology (POSTECH), Pohang, 37673, South Korea.
| | - Taiha Joo
- Department of Chemistry, Pohang University of Science and Technology (POSTECH), Pohang, 37673, South Korea.
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5
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Jeon K, Jen M, Lee S, Jang T, Pang Y. Intramolecular Charge Transfer of 1-Aminoanthraquinone and Ultrafast Solvation Dynamics of Dimethylsulfoxide. Int J Mol Sci 2021; 22:ijms222111926. [PMID: 34769357 PMCID: PMC8584543 DOI: 10.3390/ijms222111926] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2021] [Revised: 10/29/2021] [Accepted: 11/01/2021] [Indexed: 11/16/2022] Open
Abstract
The intramolecular charge transfer (ICT) of 1-aminoanthraquinone (AAQ) in the excited state strongly depends on its solvent properties, and the twisted geometry of its amino group has been recommended for the twisted ICT (TICT) state by recent theoretical works. We report the transient Raman spectra of AAQ in a dimethylsulfoxide (DMSO) solution by femtosecond stimulated Raman spectroscopy to provide clear experimental evidence for the TICT state of AAQ. The ultrafast (~110 fs) TICT dynamics of AAQ were observed from the major vibrational modes of AAQ including the νC-N + δCH and νC=O modes. The coherent oscillations in the vibrational bands of AAQ strongly coupled to the nuclear coordinate for the TICT process have been observed, which showed its anharmonic coupling to the low frequency out of the plane deformation modes. The vibrational mode of solvent DMSO, νS=O showed a decrease in intensity, especially in the hydrogen-bonded species of DMSO, which clearly shows that the solvation dynamics of DMSO, including hydrogen bonding, are crucial to understanding the reaction dynamics of AAQ with the ultrafast structural changes accompanying the TICT.
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6
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Chiariello MG, Donati G, Raucci U, Perrella F, Rega N. Structural Origin and Vibrational Fingerprints of the Ultrafast Excited State Proton Transfer of the Pyranine-Acetate Complex in Aqueous Solution. J Phys Chem B 2021; 125:10273-10281. [PMID: 34472354 DOI: 10.1021/acs.jpcb.1c05590] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The excited state proton transfer (ESPT) reaction from the photoacid 8-hydroxypyrene-1,3,6-trisulfonic acid (HPTS or pyranine) to an acetate molecule has been investigated in explicit aqueous solution via excited state ab initio molecular dynamics simulations based on hybrid quantum/molecular mechanics (QM/MM) potentials. In all the trajectories, the direct proton transfer has been observed in the excited state within 1 ps. We find that the initial structural configuration extracted from the ground state distribution strongly affects the ESPT kinetics. Indeed, the relative orientation of the proton donor-acceptor pair and the presence of a water molecule hydrogen bonded to the phenolic acid group of the pyranine are the key factors to facilitate the ESPT. Furthermore, we analyze the vibrational fingerprints of the ESPT reaction, reproducing the blue shift of the acetate CO stretching (COac), from 1666 to 1763 cm-1 testifying the transformation of acetate to acetic acid. Finally, our findings suggest that the acetate CC stretching (CCac) is also sensitive to the progress of the ESPT reaction. The CCac stretching is indeed ruled by the two vibrational modes (928 and 1426 cm-1), that in the excited state are alternately activated when the proton is shared or bound to the donor/acceptor, respectively.
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Affiliation(s)
- Maria Gabriella Chiariello
- Dipartimento di Scienze Chimiche, Università di Napoli Federico II, Complesso Universitario di M.S. Angelo, via Cintia, I-80126 Napoli, Italy
| | - Greta Donati
- Dipartimento di Scienze Chimiche, Università di Napoli Federico II, Complesso Universitario di M.S. Angelo, via Cintia, I-80126 Napoli, Italy
| | - Umberto Raucci
- Dipartimento di Scienze Chimiche, Università di Napoli Federico II, Complesso Universitario di M.S. Angelo, via Cintia, I-80126 Napoli, Italy
| | - Fulvio Perrella
- Dipartimento di Scienze Chimiche, Università di Napoli Federico II, Complesso Universitario di M.S. Angelo, via Cintia, I-80126 Napoli, Italy
| | - Nadia Rega
- Dipartimento di Scienze Chimiche, Università di Napoli Federico II, Complesso Universitario di M.S. Angelo, via Cintia, I-80126 Napoli, Italy.,CRIB Center for Advanced Biomaterials for Healthcare, Piazzale Tecchio, 80-80125 Napoli, Italy
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7
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Chiariello MG, Raucci U, Donati G, Rega N. Water-Mediated Excited State Proton Transfer of Pyranine-Acetate in Aqueous Solution: Vibrational Fingerprints from Ab Initio Molecular Dynamics. J Phys Chem A 2021; 125:3569-3578. [PMID: 33900071 PMCID: PMC8279639 DOI: 10.1021/acs.jpca.1c00692] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
![]()
In this work, we
simulate the excited state proton transfer (ESPT)
reaction involving the pyranine photoacid and an acetate molecule
as proton acceptor, connected by a bridge water molecule. We employ
ab initio molecular dynamics combined with an hybrid quantum/molecular
mechanics (QM/MM) framework. Furthermore, a time-resolved vibrational
analysis based on the wavelet-transform allows one to identify two
low frequency vibrational modes that are fingerprints of the ESPT
event: a ring wagging and ring breathing. Their composition suggests
their key role in optimizing the structure of the proton donor–acceptor
couple and promoting the ESPT event. We find that the choice of the
QM/MM partition dramatically affects the photoinduced reactivity of
the system. The QM subspace was gradually extended including the water
molecules directly interacting with the pyranine–water–acetate
system. Indeed, the ESPT reaction takes place when the hydrogen bond
network around the reactive system is taken into account at full QM
level.
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Affiliation(s)
- Maria Gabriella Chiariello
- Dipartimento di Scienze Chimiche, Università di Napoli Federico II, Complesso Universitario di M.S. Angelo, via Cintia, I-80126 Napoli, Italy
| | - Umberto Raucci
- Dipartimento di Scienze Chimiche, Università di Napoli Federico II, Complesso Universitario di M.S. Angelo, via Cintia, I-80126 Napoli, Italy
| | - Greta Donati
- Dipartimento di Scienze Chimiche, Università di Napoli Federico II, Complesso Universitario di M.S. Angelo, via Cintia, I-80126 Napoli, Italy
| | - Nadia Rega
- Dipartimento di Scienze Chimiche, Università di Napoli Federico II, Complesso Universitario di M.S. Angelo, via Cintia, I-80126 Napoli, Italy.,Centro Interdipartimentale di Ricerca sui Biomateriali (CRIB) Piazzale Tecchio, Largo Barsanti e Matteucci, I-80125 Napoli, Italy
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8
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Lee C, Chung S, Song H, Rhee YM, Lee E, Joo T. Excited State Proton Transfer of Quinone Cyanine 9: Implications on the Origin of Super‐Photoacidity. CHEMPHOTOCHEM 2020. [DOI: 10.1002/cptc.202000254] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Changmin Lee
- Department of Chemistry Pohang University of Science and Technology (POSTECH) Pohang 37673 Republic of Korea
| | - Seyoung Chung
- Department of Chemistry Pohang University of Science and Technology (POSTECH) Pohang 37673 Republic of Korea
| | - Hayoung Song
- Department of Chemistry Pohang University of Science and Technology (POSTECH) Pohang 37673 Republic of Korea
| | - Young Min Rhee
- Department of Chemistry Korea Advanced Institute of Science and Technology (KAIST) Daejeon 34141 Republic of Korea
| | - Eunsung Lee
- Department of Chemistry Pohang University of Science and Technology (POSTECH) Pohang 37673 Republic of Korea
| | - Taiha Joo
- Department of Chemistry Pohang University of Science and Technology (POSTECH) Pohang 37673 Republic of Korea
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9
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Thomaz JE, Walker AR, Van Wyck SJ, Meisner J, Martinez TJ, Fayer MD. Proton Transfer Dynamics in the Aprotic Proton Accepting Solvent 1-Methylimidazole. J Phys Chem B 2020; 124:7897-7908. [PMID: 32790382 DOI: 10.1021/acs.jpcb.0c05525] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The dynamics of proton transfer to the aprotic solvent 1-methylimidazole (MeIm, proton acceptor) from the photoacid 8-hydroxypyrene-1,3,6-trisulfonic acid trisodium salt (HPTS) was investigated using fast fluorescence measurements. The closely related molecule, 8-methoxypyrene-1,3,6-trisulfonic acid trisodium salt (MPTS), which is not a photoacid, was also studied for comparison. Following optical excitation, the wavelength-dependent population dynamics of HPTS in MeIm resulting from the deprotonation process were collected over the entire fluorescence emission window. Analysis of the time-dependent fluorescence spectra revealed four distinct fluorescence bands that appear and decay on different time scales. We label these four states as protonated (P), associated I (AI), associated II (AII), and deprotonated (D). We find that the simple kinetic scheme of P → AI → AII → D is not consistent with the data. Instead, the kinetic scheme that describes the data has P decaying into AI, which mainly goes on to deprotonation (D), but AI can also feed into AII. AII can return to AI or decay to the ground state, but does not deprotonate within experimental error. Quantum chemistry and excited state QM/MM Born-Oppenheimer molecular dynamics simulations indicate that AI and AII are two H-bonding conformations of MeIm to the HPTS hydroxyl, axial, and equatorial, respectively.
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Affiliation(s)
- Joseph E Thomaz
- Department of Chemistry, Stanford University, Stanford, California 94305, United States
| | - Alice R Walker
- Department of Chemistry, Stanford University, Stanford, California 94305, United States.,SLAC National Accelerator Laboratory, Menlo Park, California 94025, United States
| | - Stephen J Van Wyck
- Department of Chemistry, Stanford University, Stanford, California 94305, United States
| | - Jan Meisner
- Department of Chemistry, Stanford University, Stanford, California 94305, United States.,SLAC National Accelerator Laboratory, Menlo Park, California 94025, United States
| | - Todd J Martinez
- Department of Chemistry, Stanford University, Stanford, California 94305, United States.,SLAC National Accelerator Laboratory, Menlo Park, California 94025, United States
| | - Michael D Fayer
- Department of Chemistry, Stanford University, Stanford, California 94305, United States.,SLAC National Accelerator Laboratory, Menlo Park, California 94025, United States
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10
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Kim J, Kim CH, Burger C, Park M, Kling MF, Kim DE, Joo T. Non-Born-Oppenheimer Molecular Dynamics Observed by Coherent Nuclear Wave Packets. J Phys Chem Lett 2020; 11:755-761. [PMID: 31927968 DOI: 10.1021/acs.jpclett.9b03488] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
The reaction dynamics of a photochemical reaction is typically described by reaction coordinates based on the Born-Oppenheimer (BO) approximation. A strong interaction between electrons and nuclei, conventionally occurring at conical intersections, however, breaks the BO approximation and has major consequences for the efficiency of a photochemical reaction. Despite its importance, related studies into the non-BO dynamics are scarce. Here, we investigate the non-BO dynamics of excited-state intramolecular proton transfer (ESIPT) occurring in 10-hydroxybenzo[h]quinoline (HBQ). Two coherent vibrational modes at 237 and 794 cm-1 representing molecular dynamics on a diabatic surface in HBQ are identified by a wave packet analysis based on a transient absorption measurement with a time resolution of 11 fs and with a density functional theory-based model calculation. It is also revealed that the strong Coulomb field effect in HBQ leads to the completion of ESIPT within about two cycles of the OH stretching mode. The work paves the way for time-domain studies of molecular dynamics beyond the BO approximation in other photochemical reactions.
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Affiliation(s)
- JunWoo Kim
- Department of Chemistry , Pohang University of Science and Technology (POSTECH) , Pohang 37673 , Korea
| | - Chul Hoon Kim
- Center for Attosecond Science and Technology , Max Planck POSTECH/Korea Research Initiative (MPK) , Pohang 37673 , Korea
| | - Christian Burger
- Max Plank Institute of Quantum Optics , D-85748 Garching , Germany
- Physics Department , Ludwig-Maximilians-Universität Munich , D-85748 Garching , Germany
| | - Myeongkee Park
- Department of Chemistry , Pohang University of Science and Technology (POSTECH) , Pohang 37673 , Korea
| | - Matthias F Kling
- Max Plank Institute of Quantum Optics , D-85748 Garching , Germany
- Physics Department , Ludwig-Maximilians-Universität Munich , D-85748 Garching , Germany
| | - Dong Eon Kim
- Center for Attosecond Science and Technology , Max Planck POSTECH/Korea Research Initiative (MPK) , Pohang 37673 , Korea
- Department of Physics , Pohang University of Science and Technology (POSTECH) , Pohang 37673 , Korea
| | - Taiha Joo
- Department of Chemistry , Pohang University of Science and Technology (POSTECH) , Pohang 37673 , Korea
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11
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Fang C, Tang L, Chen C. Unveiling coupled electronic and vibrational motions of chromophores in condensed phases. J Chem Phys 2019; 151:200901. [PMID: 31779327 DOI: 10.1063/1.5128388] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
The quest for capturing molecular movies of functional systems has motivated scientists and engineers for decades. A fundamental understanding of electronic and nuclear motions, two principal components of the molecular Schrödinger equation, has the potential to enable the de novo rational design for targeted functionalities of molecular machines. We discuss the development and application of a relatively new structural dynamics technique, femtosecond stimulated Raman spectroscopy with broadly tunable laser pulses from the UV to near-IR region, in tracking the coupled electronic and vibrational motions of organic chromophores in solution and protein environments. Such light-sensitive moieties hold broad interest and significance in gaining fundamental knowledge about the intramolecular and intermolecular Hamiltonian and developing effective strategies to control macroscopic properties. Inspired by recent experimental and theoretical advances, we focus on the in situ characterization and spectroscopy-guided tuning of photoacidity, excited state proton transfer pathways, emission color, and internal conversion via a conical intersection.
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Affiliation(s)
- Chong Fang
- Department of Chemistry, Oregon State University, Corvallis, Oregon 97331, USA
| | - Longteng Tang
- Department of Chemistry, Oregon State University, Corvallis, Oregon 97331, USA
| | - Cheng Chen
- Department of Chemistry, Oregon State University, Corvallis, Oregon 97331, USA
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12
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Jen M, Jeon K, Lee S, Hwang S, Chung WJ, Pang Y. Ultrafast intramolecular proton transfer reactions and solvation dynamics of DMSO. STRUCTURAL DYNAMICS (MELVILLE, N.Y.) 2019; 6:064901. [PMID: 31867409 PMCID: PMC6920016 DOI: 10.1063/1.5129446] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/28/2019] [Accepted: 11/21/2019] [Indexed: 05/27/2023]
Abstract
Ultrafast intramolecular proton transfers of 1,2-dihydroxyanthraquinone (alizarin-h2) and its deuterated product (alizarin-d2) in dimethyl sulfoxide (DMSO) have been investigated by femtosecond stimulated Raman spectroscopy. The population dynamics in the solute vibrational mode of νC=O and the coherent oscillations observed in all of the skeletal vibrational modes νC=O and νC=C clearly showed the ultrafast excited-state intramolecular proton transfer dynamics of 110 and 170 fs for alizarin-h2 and alizarin-d2, respectively. Interestingly, we have observed that the solvent vibrational modes νS=O and νCSC may also represent ultrafast structural dynamics at the frequencies for its "free" or "aggregated" species. From the kinetic analysis of the νS=O and νCSC modes of DMSO, the ultrafast changes in the solvation or intermolecular interactions between DMSO molecules initiated by the structural changes of solute molecules have been thoroughly investigated. We propose that the solvent vibrational modes νS=O and νCSC of DMSO can be used as a "sensor" for ultrafast chemical reactions accompanying the structural changes and subsequent solute-solvent interactions.
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Affiliation(s)
| | | | - Sebok Lee
- Department of Chemistry, Gwangju Institute of Science and Technology, 123 Cheomdangwagi-ro, Buk-gu, Gwangju 61005, South Korea
| | - Sunjoo Hwang
- Department of Chemistry, Gwangju Institute of Science and Technology, 123 Cheomdangwagi-ro, Buk-gu, Gwangju 61005, South Korea
| | - Won-jin Chung
- Department of Chemistry, Gwangju Institute of Science and Technology, 123 Cheomdangwagi-ro, Buk-gu, Gwangju 61005, South Korea
| | - Yoonsoo Pang
- Department of Chemistry, Gwangju Institute of Science and Technology, 123 Cheomdangwagi-ro, Buk-gu, Gwangju 61005, South Korea
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13
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Amoruso G, Taylor VCA, Duchi M, Goodband E, Oliver TAA. Following Bimolecular Excited-State Proton Transfer between Hydroxycoumarin and Imidazole Derivatives. J Phys Chem B 2019; 123:4745-4756. [DOI: 10.1021/acs.jpcb.9b01475] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Affiliation(s)
- Giordano Amoruso
- School of Chemistry, Cantock’s Close, University of Bristol, Bristol BS8 1TS, United Kingdom
| | - Victoria C. A. Taylor
- School of Chemistry, Cantock’s Close, University of Bristol, Bristol BS8 1TS, United Kingdom
- Bristol Centre for Functional Nanomaterials, School of Physics, University of Bristol, Bristol BS8 1TH, United Kingdom
| | - Marta Duchi
- School of Chemistry, Cantock’s Close, University of Bristol, Bristol BS8 1TS, United Kingdom
| | - Emma Goodband
- School of Chemistry, Cantock’s Close, University of Bristol, Bristol BS8 1TS, United Kingdom
| | - Thomas A. A. Oliver
- School of Chemistry, Cantock’s Close, University of Bristol, Bristol BS8 1TS, United Kingdom
- Bristol Centre for Functional Nanomaterials, School of Physics, University of Bristol, Bristol BS8 1TH, United Kingdom
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14
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Tang L, Zhu L, Wang Y, Fang C. Uncovering the Hidden Excited State toward Fluorescence of an Intracellular pH Indicator. J Phys Chem Lett 2018; 9:4969-4975. [PMID: 30111103 DOI: 10.1021/acs.jpclett.8b02281] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Intracellular pH (pHi) imaging is of paramount importance for life sciences. In this work, we implement the ultrafast electronic and stimulated Raman spectroscopies to unravel the fluorescence mechanism of an excitation-ratiometric pHi indicator in basic aqueous solution. After photoexcitation of the pHi indicator HPTS, a hidden charge-transfer (CT) state following the locally excited (LE) state is uncovered as an essential step prior to fluorescence and this LE → CT transition is gated by ultrafast solvation dynamics. A 835 cm-1 intermolecular vibrational mode is identified to potentially facilitate the CT-state formation on the 700 fs time scale. Dynamic correlation with the other excited-state Raman marker bands suggests that the transition between transient electronic states is aided by solvation events mostly in the molecular plane of HPTS. These vivid structural dynamics insights can enable the rational design of more efficient and bright pHi indicators in an H-bonding environment with controllable properties.
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Affiliation(s)
- Longteng Tang
- Department of Chemistry , Oregon State University , Corvallis , Oregon 97331 , United States
| | - Liangdong Zhu
- Department of Chemistry , Oregon State University , Corvallis , Oregon 97331 , United States
| | - Yanli Wang
- Department of Chemistry , Oregon State University , Corvallis , Oregon 97331 , United States
| | - Chong Fang
- Department of Chemistry , Oregon State University , Corvallis , Oregon 97331 , United States
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15
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Abstract
As one of the most fundamental processes, excited-state proton transfer (ESPT) plays a major role in both chemical and biological systems. In the past several decades, experimental and theoretical studies on ESPT systems have attracted considerable attention because of their tremendous potential in fluorescent probes, biological imaging, white-light-emitting materials, and organic optoelectronic materials. ESPT is related to fluorescence properties and usually occurs on an ultrafast time scale at or below 100 fs. Consequently, steady-state and femtosecond time-resolved absorption, fluorescence, and vibrational spectra have been used to explore the mechanism of ESPT. However, based on previous experimental studies, direct information, such as transition state geometries, energy barrier, and potential energy surface (PES) of the ESPT reaction, is difficult to obtain. These data are important for unravelling the detailed mechanism of ESPT reaction and can be obtained from state-of-the-art ab initio excited-state calculations. In recent years, an increasing number of experimental and theoretical studies on the detailed mechanism of ESPT systems have led to tremendous progress. This Account presents the recent advances in theoretical studies, mainly those from our group. We focus on the cases where the theoretical studies are of great importance and indispensable, such as resolving the debate on the stepwise and concerted mechanism of excited-state double proton transfer (ESDPT), revealing the sensing mechanism of ESPT chemosensors, illustrating the effect of intermolecular hydrogen bonding on the excited-state intramolecular proton transfer (ESIPT) reaction, investigating the fluorescence quenching mechanism of ESPT systems by twisting process, and determining the size of the solute·(solvent) n cluster for the solvent-assisted ESPT reaction. Through calculation of vertical excitation energies, optimization of excited-state geometries, and construction of PES of the ESPT reactions, we provide modifications to experimentally proposed mechanisms or completely new mechanism. Our proposed new and inspirational mechanisms based on theoretical studies can successfully explain the previous experimental results; some of the mechanisms have been further confirmed by experimental studies and provided guidance for researchers to design new ESPT chemosensors. Determination of the energy barrier from an accurate PES is the key to explore the ESPT mechanism with theoretical methods. This approach becomes complicated when the charge transfer state is involved for time-dependent density functional theory (TDDFT) method and optimally tuned range-separated TDDFT provides an alternative way. To unveil the driving force of ESPT reaction, the excited-state molecular dynamics combined with the intrinsic reaction coordinate calculations can be employed. These advanced approaches should be used for further studies on ESPT systems.
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Affiliation(s)
- Panwang Zhou
- State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Science, Dalian 116023, Liaoning, China
| | - Keli Han
- State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Science, Dalian 116023, Liaoning, China
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16
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Tang L, Wang Y, Zhu L, Lee C, Fang C. Correlated Molecular Structural Motions for Photoprotection after Deep-UV Irradiation. J Phys Chem Lett 2018; 9:2311-2319. [PMID: 29672054 DOI: 10.1021/acs.jpclett.8b00999] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Exposure to ultraviolet (UV) light could cause photodamage to biomolecular systems and degrade optoelectronic devices. To mitigate such detrimental effects from the bottom up, we strategically select a photosensitive molecule pyranine and implement femtosecond electronic and Raman spectroscopies to elucidate its ultrafast photoprotection mechanisms in solution. Our results show that pyranine undergoes excited-state proton transfer in water, while this process is blocked in methanol regardless of excitation wavelengths (267, 400 nm). After 267 nm irradiation, the molecule relaxes from a higher lying electronic state into a lower lying singlet state with a <300 fs time constant, followed by solvation events. Transient Raman marker bands exhibit different patterns of intensity dynamics and frequency shift that elucidate the real-time interplay among conformational motions, photochemical reaction, and vibrational cooling after excitation. More energetic photons are revealed to selectively enhance certain relaxation pathways. These mechanistic findings offer new guidelines to improve the UV tolerance and stability of the engineered functional molecules in materials and life sciences.
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Affiliation(s)
- Longteng Tang
- Department of Chemistry , Oregon State University , Corvallis , Oregon 97331 , United States
| | - Yanli Wang
- Department of Chemistry , Oregon State University , Corvallis , Oregon 97331 , United States
| | - Liangdong Zhu
- Department of Chemistry , Oregon State University , Corvallis , Oregon 97331 , United States
| | - Che Lee
- Department of Chemistry , Oregon State University , Corvallis , Oregon 97331 , United States
| | - Chong Fang
- Department of Chemistry , Oregon State University , Corvallis , Oregon 97331 , United States
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Chiariello MG, Rega N. Exploring Nuclear Photorelaxation of Pyranine in Aqueous Solution: an Integrated Ab-Initio Molecular Dynamics and Time Resolved Vibrational Analysis Approach. J Phys Chem A 2018; 122:2884-2893. [DOI: 10.1021/acs.jpca.7b12371] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Maria Gabriella Chiariello
- Dipartimento di Scienze Chimiche, Università di Napoli Federico II, Complesso Universitario di M.S.Angelo, via Cintia, I-80126 Napoli, Italy
| | - Nadia Rega
- Dipartimento di Scienze Chimiche, Università di Napoli Federico II, Complesso Universitario di M.S.Angelo, via Cintia, I-80126 Napoli, Italy
- Interdisciplinary Research Centre on Biomaterials (CRIB) Università di Napoli Federico II, Piazzale Tecchio 80, I-80125, Napoli, Italy
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18
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Bhatta SR, Mondal B, Vijaykumar G, Thakur A. ICT–Isomerization-Induced Turn-On Fluorescence Probe with a Large Emission Shift for Mercury Ion: Application in Combinational Molecular Logic. Inorg Chem 2017; 56:11577-11590. [DOI: 10.1021/acs.inorgchem.7b01304] [Citation(s) in RCA: 42] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Affiliation(s)
- Sushil Ranjan Bhatta
- Department of Chemistry, National Institute of Technology Rourkela, Rourkela-769 008, Odisha, India
| | - Bijan Mondal
- Department
of Chemistry, Indian Institute of Technology Madras, Chennai-600 036, India
| | - Gonela Vijaykumar
- Department of Chemical
Science, Indian Institute of Science Education and Research Kolkata, Mohanpur-741 246, India
| | - Arunabha Thakur
- Department of Chemistry, National Institute of Technology Rourkela, Rourkela-769 008, Odisha, India
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