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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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López Peña HA, Ampadu Boateng D, McPherson SL, Tibbetts KM. Using computational chemistry to design pump–probe schemes for measuring nitrobenzene radical cation dynamics. Phys Chem Chem Phys 2021; 23:13338-13348. [DOI: 10.1039/d1cp00360g] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Computed potential energy surfaces of the nitrobenzene cation predict suitable excitation conditions for enhancing ion yield oscillations in time-resolved measurements.
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Wu JY, Cheng PY. Ultrafast Protonation of an Amide: Photoionization-Induced Proton Transfer in Phenol-Dimethylformamide Complex Cation. J Phys Chem A 2019; 123:10700-10713. [DOI: 10.1021/acs.jpca.9b09651] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Affiliation(s)
- Jun-Yi Wu
- Department of Chemistry, National Tsing Hua University, Hsinchu 30043, Taiwan, R.
O. C
| | - Po-Yuan Cheng
- Department of Chemistry, National Tsing Hua University, Hsinchu 30043, Taiwan, R.
O. C
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Wei SC, Ho JW, Yen HC, Shi HQ, Cheng LH, Weng CN, Chou WK, Chiu CC, Cheng PY. Ultrafast Excited-State Dynamics of Hydrogen-Bonded Cytosine Microsolvated Clusters with Protic and Aprotic Polar Solvents. J Phys Chem A 2018; 122:9412-9425. [PMID: 30452255 DOI: 10.1021/acs.jpca.8b09526] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Microsolvation effects on the ultrafast excited-state deactivation dynamics of cytosine (Cy) were studied in hydrogen-bonded Cy clusters with protic and aprotic solvents using mass-resolved femtosecond pump-probe ionization spectroscopy. Two protic solvents, water (H2O) and methanol (MeOH), and one aprotic solvent, tetrahydrofuran (THF), were investigated, and transients of Cy·(H2O)1-6, Cy·(MeOH)1-3, and Cy·THF microsolvated clusters produced in supersonic expansions were measured. With the aid of electronic structure calculations, we assigned the observed dynamics to the low-energy isomers of various Cy clusters and discussed the microsolvation effect on the excited-state deactivation dynamics. With the protic solvents only the microsolvated clusters of Cy keto tautomer were observed. The observed decay time constants of Cy·(H2O) n are 0.5 ps for n = 1 and ∼0.2-0.25 ps for n = 2-6. For Cy·(MeOH) n clusters, the decay time constant for n = 1 cluster is similar to that of the Cy monohydrate, but for n = 2 and 3 the decays are about a factor of 2 slower than the corresponding microhydrates. With the aprotic solvent, THF, hydrogen-bonded complexes of both keto and enol tautomers are present in the beam. The keto-Cy·THF shows a decay similar to that of the keto-Cy monomer, whereas the enol-Cy·THF exhibits a 2-fold slower decay than the enol-Cy monomer, suggesting an increase in the barrier to excited-state deactivation upon binding of one THF molecule to the enol form of Cy.
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Affiliation(s)
- Shih-Chun Wei
- Department of Chemistry , National Tsing Hua University , Hsinchu , Taiwan 30043 , Republic of China
| | - Jr-Wei Ho
- Department of Chemistry , National Tsing Hua University , Hsinchu , Taiwan 30043 , Republic of China
| | - Hung-Chien Yen
- Department of Chemistry , National Tsing Hua University , Hsinchu , Taiwan 30043 , Republic of China
| | - Hui-Qi Shi
- Department of Chemistry , National Tsing Hua University , Hsinchu , Taiwan 30043 , Republic of China
| | - Li-Hao Cheng
- Department of Chemistry , National Tsing Hua University , Hsinchu , Taiwan 30043 , Republic of China
| | - Chih-Nan Weng
- Department of Chemistry , National Tsing Hua University , Hsinchu , Taiwan 30043 , Republic of China
| | - Wei-Kuang Chou
- Department of Chemistry , National Tsing Hua University , Hsinchu , Taiwan 30043 , Republic of China
| | - Chih-Chung Chiu
- Department of Chemistry , National Tsing Hua University , Hsinchu , Taiwan 30043 , Republic of China
| | - Po-Yuan Cheng
- Department of Chemistry , National Tsing Hua University , Hsinchu , Taiwan 30043 , Republic of China
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Chatterjee P, Ghosh AK, Samanta M, Chakraborty T. Barrierless Proton Transfer in the Weak C-H···O Hydrogen Bonded Methacrolein Dimer upon Nonresonant Multiphoton Ionization in the Gas Phase. J Phys Chem A 2018; 122:5563-5573. [PMID: 29878781 DOI: 10.1021/acs.jpca.8b02597] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Intermolecular proton transfer (IMPT) in a C-H···O hydrogen bonded dimer of an α,β-unsaturated aldehyde, methacrolein (MC), upon nonresonant multiphoton ionization by 532 nm laser pulses (10 ns), has been investigated using time-of-flight (TOF) mass spectrometry under supersonic cooling condition. The mass peaks corresponding to both the protonated molecular ion [(MC)H+] and intact dimer cation [(MC)2]•+ show up in the mass spectra, and the peak intensity of the former increases proportionately with the latter with betterment of the jet cooling conditions. The observations indicate that [(MC)2]•+ is the likely precursor of (MC)H+ and, on the basis of electronic structure calculations, IMPT in the dimer cation has been shown to be the key reaction for formation of the latter. Laser power dependences of ion yields indicate that at this wavelength the dimer is photoionized by means of 4-photon absorption process, and the total 4-photon energy is nearly the same as the predicted vertical ionization energy of the dimer. Electronic structure calculations reveal that the optimized structures of [(MC)2]•+ correspond to a proton transferred configuration wherein the aldehydic hydrogen is completely shifted to the carbonyl oxygen of the neighboring moiety. Potential energy scans along the C-H···O coordinate also show that the IMPT in [(MC)2]•+ is a barrierless process.
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Affiliation(s)
- Piyali Chatterjee
- Department of Physical Chemistry , Indian Association for the Cultivation of Science , 2A Raja S C Mullick Road , Jadavpur, Kolkata 700032 , India
| | - Arup K Ghosh
- Department of Chemistry , Dharmsinh Desai University , Nadiad 387001 , Gujarat , India
| | - Monoj Samanta
- Department of Physical Chemistry , Indian Association for the Cultivation of Science , 2A Raja S C Mullick Road , Jadavpur, Kolkata 700032 , India
| | - Tapas Chakraborty
- Department of Physical Chemistry , Indian Association for the Cultivation of Science , 2A Raja S C Mullick Road , Jadavpur, Kolkata 700032 , India
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Shen CC, Tsai TT, Wu JY, Ho JW, Chen YW, Cheng PY. Watching proton transfer in real time: Ultrafast photoionization-induced proton transfer in phenol-ammonia complex cation. J Chem Phys 2017; 147:164302. [PMID: 29096460 DOI: 10.1063/1.5001375] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
In this paper, we give a full account of our previous work [C. C. Shen et al., J. Chem. Phys. 141, 171103 (2014)] on the study of an ultrafast photoionization-induced proton transfer (PT) reaction in the phenol-ammonia (PhOH-NH3) complex using ultrafast time-resolved ion photofragmentation spectroscopy implemented by the photoionization-photofragmentation pump-probe detection scheme. Neutral PhOH-NH3 complexes prepared in a free jet are photoionized by femtosecond 1 + 1 resonance-enhanced multiphoton ionization via the S1 state. The evolving cations are then probed by delayed pulses that result in ion fragmentation, and the ionic dynamics is followed by measuring the parent-ion depletion as a function of the pump-probe delay time. By comparing with systems in which PT is not feasible and the steady-state ion photofragmentation spectra, we concluded that the observed temporal evolutions of the transient ion photofragmentation spectra are consistent with an intracomplex PT reaction after photoionization from the initial non-PT to the final PT structures. Our experiments revealed that PT in [PhOH-NH3]+ cation proceeds in two distinct steps: an initial impulsive wave-packet motion in ∼70 fs followed by a slower relaxation of about 1 ps that stabilizes the system into the final PT configuration. These results indicate that for a barrierless PT system, even though the initial PT motions are impulsive and ultrafast, the time scale to complete the reaction can be much slower and is determined by the rate of energy dissipation into other modes.
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Affiliation(s)
- Ching-Chi Shen
- Department of Chemistry, National Tsing Hua University, Hsinchu, Taiwan 30043, Republic of China
| | - Tsung-Ting Tsai
- Department of Chemistry, National Tsing Hua University, Hsinchu, Taiwan 30043, Republic of China
| | - Jun-Yi Wu
- Department of Chemistry, National Tsing Hua University, Hsinchu, Taiwan 30043, Republic of China
| | - Jr-Wei Ho
- Department of Chemistry, National Tsing Hua University, Hsinchu, Taiwan 30043, Republic of China
| | - Yi-Wei Chen
- Department of Chemistry, National Tsing Hua University, Hsinchu, Taiwan 30043, Republic of China
| | - Po-Yuan Cheng
- Department of Chemistry, National Tsing Hua University, Hsinchu, Taiwan 30043, Republic of China
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Chatterjee P, Ghosh AK, Chakraborty T. Hydrogen bond induced HF elimination from photoionized fluorophenol dimers in the gas phase. J Chem Phys 2017; 146:084310. [DOI: 10.1063/1.4976988] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Affiliation(s)
- Piyali Chatterjee
- Department of Physical Chemistry, Indian Association for the Cultivation of Science, 2A Raja S C Mullick Road, Jadavpur, Kolkata 700032, India
| | - Arup K. Ghosh
- Department of Physical Chemistry, Indian Association for the Cultivation of Science, 2A Raja S C Mullick Road, Jadavpur, Kolkata 700032, India
| | - Tapas Chakraborty
- Department of Physical Chemistry, Indian Association for the Cultivation of Science, 2A Raja S C Mullick Road, Jadavpur, Kolkata 700032, India
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Jin XY, Wang F, Cong H, Tao Z. Host–guest interactions of hemicucurbiturils with aminophenols. J INCL PHENOM MACRO 2016. [DOI: 10.1007/s10847-016-0653-9] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
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