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Pan X, Han T, Long J, Xie B, Du Y, Zhao Y, Zheng X, Xue J. Excited state proton transfer of triplet state p-nitrophenylphenol to amine and alcohol: a spectroscopic and kinetic study. Phys Chem Chem Phys 2022; 24:18427-18434. [PMID: 35881619 DOI: 10.1039/d2cp02503e] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Hydroxyaromatic compounds (ArOHs) have a wide range of applications in catalytic synthesis and biological processes due to their increased acidity upon photo-excitation. The proton transfer of ArOHs via the excited singlet state has been extensively studied. However, there has still been a debate on the unique type of ArOH that can undergo an ultrafast intersystem crossing. The nitro group in p-nitrophenylphenol (NO2-Bp-OH) enhances the spin-orbit coupling between excited singlet states and the triplet manifold, enabling ultrafast intersystem crossing and the formation of the long-lived lowest excited triplet state (T1) with a high yield. In this work, we used time-resolved transient absorption to investigate the excited state proton transfer of NO2-Bp-OH in its T1 state to t-butylamine, methanol, and ethanol. The T1 state of the deprotonated form NO2-Bp-O- was first observed and identified in the case of t-butylamine. Kinetic analysis demonstrates that the formation of the hydrogen-bonded complex with methanol and ethanol as proton acceptors involves their trimers. The alcohol oligomer size required in the excited state proton transfer process is dependent on the excited acidity of photoacid.
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Affiliation(s)
- Xinghang Pan
- Department of Chemistry, Zhejiang Sci-Tech University, Hangzhou, 310018, China.
| | - Ting Han
- Department of Chemistry, Zhejiang Sci-Tech University, Hangzhou, 310018, China.
| | - Jing Long
- Department of Chemistry, Zhejiang Sci-Tech University, Hangzhou, 310018, China.
| | - Binbin Xie
- Hangzhou Institute of Advanced Studies, Zhejiang Normal University, Hangzhou, 310018, China
| | - Yong Du
- Centre for THz Research, China Jiliang University, Hangzhou, 310018, China
| | - Yanying Zhao
- Department of Chemistry, Zhejiang Sci-Tech University, Hangzhou, 310018, China. .,Key Laboratory of Surface & Interface Science of Polymer Materials of Zhejiang Province, Zhejiang Sci-Tech University, Hangzhou, 310018, China
| | - Xuming Zheng
- Department of Chemistry, Zhejiang Sci-Tech University, Hangzhou, 310018, China.
| | - Jiadan Xue
- Department of Chemistry, Zhejiang Sci-Tech University, Hangzhou, 310018, China. .,Key Laboratory of Surface & Interface Science of Polymer Materials of Zhejiang Province, Zhejiang Sci-Tech University, Hangzhou, 310018, China
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Nho HW, Adhikari A, Kwon OH. Ultrafast Excited-State Proton Transfer of a Cationic Superphotoacid in a Nanoscopic Water Pool. J Phys Chem B 2022; 126:1275-1283. [PMID: 35119852 DOI: 10.1021/acs.jpcb.1c09070] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The excited-state proton transfer (ESPT) of a cationic superphotoacid, N-methyl-7-hydroxyquinolium, was studied within the water pool of an anionic aerosol-OT (AOT), bis(2-ethylhexyl) sulfosuccinate, reverse micelle (RM). Previously, we had found that the cationic photoacid residing at the anionic AOT interface was conducive to ESPT to the bound water having concentric heterogeneity on the time scale of hundreds of picoseconds to nanoseconds. In our present study, on the time scale of hundreds of femtoseconds to a few tens of picoseconds, the photoacid underwent an ultrafast ESPT influenced by mobile water constituting the core of the RM. The two subpopulations of the core water molecules that determine the ultrafast biphasic deprotonation of the photoacid on time scales differing by an order of magnitude were identified. The core water molecules solvating the counteranion of the photoacid showed a higher basicity than typical water clusters in bulk resulting in ESPT on a subpicosecond time scale. Bare water clusters sensed by the photoacid showed a slower ESPT, over several picoseconds, as typically limited by the rotational motion of water molecules for similar types of the photoacid.
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Affiliation(s)
- Hak-Won Nho
- Department of Chemistry, College of Natural Sciences, Ulsan National Institute of Science and Technology (UNIST), Ulsan 44919, Republic of Korea.,Center for Soft and Living Matter, Institute for Basic Science (IBS), Ulsan 44919, Republic of Korea
| | - Aniruddha Adhikari
- Department of Chemistry, College of Natural Sciences, Ulsan National Institute of Science and Technology (UNIST), Ulsan 44919, Republic of Korea
| | - Oh-Hoon Kwon
- Department of Chemistry, College of Natural Sciences, Ulsan National Institute of Science and Technology (UNIST), Ulsan 44919, Republic of Korea.,Center for Soft and Living Matter, Institute for Basic Science (IBS), Ulsan 44919, Republic of Korea
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Acid–base
reaction of a
super‐photoacid
with a cooperative amide
hydrogen‐bonded
chain. B KOREAN CHEM SOC 2022. [DOI: 10.1002/bkcs.12479] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Small-angle X-ray scattering as an effective tool to understand the structure and rigidity of the reverse micelles with the variation of surfactant. J Mol Liq 2021. [DOI: 10.1016/j.molliq.2021.115302] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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Nho HW, Park JH, Adhikari A, Kwon OH. Acid–base reaction of a cationic hydration probe in vicinity of anionic interface of AOT reverse micelles. J Mol Liq 2021. [DOI: 10.1016/j.molliq.2020.115270] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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Adhikari A, Park WW, Kwon OH. Hydrogen-Bond Dynamics and Energetics of Biological Water. Chempluschem 2020; 85:2657-2665. [PMID: 33305536 DOI: 10.1002/cplu.202000744] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2020] [Revised: 11/26/2020] [Indexed: 11/11/2022]
Abstract
Water molecules in the immediate vicinity of biomacromolecules and biomimetic organized assemblies often exhibit a markedly distinct behavior from that of their bulk counterparts. The overall sluggish behavior of biological water substantially affects the stability and integrity of biomolecules, as well as the successful execution of various crucial water-mediated biochemical phenomena. In this Minireview, insights are provided into the features of truncated hydrogen-bond networks that grant biological water its unique characteristics. In particular, experimental results and theoretical investigations, based on chemical kinetics, are presented that have shed light on the dynamics and energetics governing such characteristics. It is emphasized how such details help us to understand the energetics of biological water, an aspect relatively less explored than its dynamics. For instance, when biological water at hydrophilic or charged protein surfaces was explored, the free energy of H-bond breakage was found to be of the order of 0.4 kcal mol-1 higher than that of bulk water.
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Affiliation(s)
- Aniruddha Adhikari
- Department of Chemistry, Ulsan National Institute of Science and Technology (UNIST), 44919, Ulsan, Republic of Korea.,Department of Physics, UNIST, 44919, Ulsan, Republic of Korea
| | - Won-Woo Park
- Department of Chemistry, Ulsan National Institute of Science and Technology (UNIST), 44919, Ulsan, Republic of Korea
| | - Oh-Hoon Kwon
- Department of Chemistry, Ulsan National Institute of Science and Technology (UNIST), 44919, Ulsan, Republic of Korea.,Center for Soft and Living Matter, Institute for Basic Science (IBS), 44919, Ulsan, Republic of Korea
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