Size effect of water cluster on the excited-state proton transfer in aqueous solvent

Liu, Yuhui; Chu, Tianshu

doi:10.1016/j.cplett.2011.02.034

Cited by 36 publications

(17 citation statements)

References 36 publications

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“…Third, the solvent molecules can act as proton-acceptors or catalysts when proton-donating and proton-accepting groups are not directly linked by hydrogen bonding. In this situation, determination of the size of the solute·(solvent) n cluster unravels the detailed mechanism of ESPT process. − …”

Section: Solvent-assisted Espt: Determining the Size Of The Solute·(s...mentioning

confidence: 99%

“…For example, when new ESPT chromophores are developed, the design strategies and possible mechanisms are proposed based on the experimental results. − However, the suggested mechanism is usually not completely corrected and sometimes problematic, thereby requiring further theoretical studies to validate or invalidate; − this can provide guidance for developing new ESPT chromophores . When multiple protons are involved, such as in excited-state double PT (ESDPT), whether the mechanism is stepwise or concerted is usually under debate among experimental scientists; , extensive theoretical studies are necessary to resolve this controversy. − When solvent molecules participate in ESPT as proton acceptor or catalyst, the size of the solute·(solvent) n cluster is difficult to determine experimentally, and theoretical studies are necessary. − …”

Section: Introductionmentioning

confidence: 99%

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Unraveling the Detailed Mechanism of Excited-State Proton Transfer

2018

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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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Section: Solvent-assisted Espt: Determining the Size Of The Solute·(s...mentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Unraveling the Detailed Mechanism of Excited-State Proton Transfer

2018

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“…It is reported that the transformation of the ESPT from a photoacid to water is effectively controlled by the size of the water cluster and"4" is a key number regarding the number of water molecules accepting the proton [ 40,41]. As shown in Fig.…”

Section: Spectra In Aqueous Solutions Of Hclmentioning

confidence: 99%

“…7, to model the CIP, 4 water molecules are connected to the proton donor group of BOH so that the structure of the hydrated proton is similar to that of the Eigen cation (H 9 O 4 + ), where a H 3 O + core is symmetrically surrounded by 3 water molecules in room-temperature aqueous acidic solutions [42]; the butyl group is simplified as methyl to reduce computational costs. Also, since hydrogen bonding may play an important role in regulating the fluorescence property of a dye [43][44][45][46][47], the hydrogen bonding interactions between water molecules and the carbonyl groups of BOH (B 1 The TDDFT method has proven useful to theoretically investigate the hydrogen bonding interactions that occur in the excited-state [40,43]. As shown in Table 3 Table 3 Bond lengths of the optimized structures of the CIP models depicted in Fig.…”

Section: Spectra In Aqueous Solutions Of Hclmentioning

confidence: 99%

Excited-state proton transfer of 4-hydroxyl-1, 8-naphthalimide derivatives: A combined experimental and theoretical investigation

Zhang

Wang

et al. 2016

Journal of Luminescence

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The photophysical properties of N-butyl-4-hydroxyl-1, 8-naphthalimide (BOH) and N-(morpholinoethyl)-4-hydroxy-1, 8-naphthalimide (MOH) in various solvents are presented and the density functional theory (DFT) / time-dependent density functional theory (TDDFT) methods at the B3LYP/TZVP theoretical level are adopted to investigate the UV-visible absorption and emission data. An efficient intermolecular excited-state proton transfer (ESPT) reaction occurs for both compounds in DMSO, methanol and water. In aqueous solution, both BOH and MOH can be used as ratiometric pH probes and perform as strong photoacids with pKa* = −2.2, −2.4, respectively. Most interestingly, in the steady-state fluorescence spectra of BOH and MOH in concentrated HCl, an unexpected blue-shifted band is observed and assumed to originate from the contact ion pair (CIP) formed by hydronium ion and the anionic form of the photoacid resulted from ESPT. Theoretical calculations are used to simulate the CIP in the case of BOH, which afford reasonable results compared with the experimental data. Keywords: Naphthalimide Excited-state proton transfer Photoacid Contact ion pair Time-dependent density functional theory 1. Introduction Upon photoexcitation, aromatic alcohols (ROH) such as naphthols, hydroxyquinolines, and hydroxypyrenes may increase the acidity dramatically. Research on this photoinduced deprotonation is first described by Fὅrster in 1949 [1] and still attracting intensive attention in the field of biology and physical chemistry [2-11]. The Eigen-Weller model for proton transfer is used to depict this process, where the initial short-range proton transfer forms a contact ion pair (CIP) as a reaction intermediate followed by diffusion controlled separation of the ions [12-13]. © 2016. This manuscript version is made available under the Elsevier user license http://www.elsevier.com/open-access/userlicense/1.0/Recently, Brouwer and coworkers synthesized and characterized some hydroxy-substituted 1, 8-naphthalimide derived "super" photoacids, where the hydroxyl group is located at the 3 or 6 position of the naphthalimide ring [6,14]. However, for 4-hydroxyl-1, 8-naphthalimide derivatives, which are extensively used for designing turn-on or rationmetric fluorescent indicators for bioimaging [15][16][17][18][19][20][21][22][23][24][25][26][27][28][29], the photophysical properties and the excited-state proton transfer (ESPT) reactions are rarely studied [30].In this contribution, the steady-state absorption and emission spectra of two 4-hydroxyl-1, 8-naphthalimide derivatives (BOH and MOH, Scheme 1) in organic solvents and water with various pH values are recorded. The density functional theory (DFT) / time-dependent density functional theory (TDDFT) methods at B3LYP/TZVP theoretical level are adopted to investigate the UV-visible absorption and emission data. In the study of the ESPT of 5-cyano-2-naphthol in sub-and supercritical water, Kobayashi and coworkers [31] found that the band of their excited neutral (ROH*) and anionic (RO − *) species...

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“…Recently, with the perpetual development of experimental techniques and measure, more and more attention has turned to the excited state dynamical behaviors. By the light of nature, excited state intra-or inter-molecular proton transfer (ESIPT) reactions have attracted much attention [10][11][12][13][14][15][16][17][18][19].…”

Section: Introductionmentioning

confidence: 99%

Theoretical Insights into the Excited State Hydrogen Bond and ESIPT Reaction for 2-Amino-3-(2’-Benzoxazolyl)Quinoline and 2-Amino-3-(2’-Benzothiazolyl)-Quinoline

Zhang¹

2018

JAMS

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Two N-H type excited state intramolecular proton transfer (ESIPT) systems (i.e., 2-amino-3-(2'benzoxazolyl)quinoline (ABO) and 2-amino-3-(2'-benzothiazolyl)-quinoline (ABT)) have been investigated. Adopting DFT and TDDFT methods coupling with B3LYP functional and TZVP basis set, our simulations about ABO and ABT molecules have successfully reappeared experimental results, based on which the rationality of our calculations is confirmed. Using Atoms in Molecules (AIM) analytical method, we firstly explore the interactions about chemical bond and verify the formation of hydrogen bond N-H•••N for ABO and ABT in the S 0 state. Investigating the primary geometrical parameters involved in N-H•••N, we find it should be strengthened in the S 1 state. Upon photoexcitation, charge transfer phenomenon is found via frontier molecular orbitals (MOs), and charge redistribution provides the tendency of ESIPT reaction for ABO and ABT. According to our constructed potential energy curves of both S 0 and S 1 states for ABO and ABT using two kinds of methods (i.e., the elongation of N-H single bond and the weakening of H•••N hydrogen bond), we clarify the ESIPT mechanisms and explain the recovery of four-level reaction cycle. Our searching transition state (TS) structures and simulated intrinsic reaction coordinate (IRC) path further confirm the ESIPT reaction.

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Size effect of water cluster on the excited-state proton transfer in aqueous solvent

Cited by 36 publications

References 36 publications

Unraveling the Detailed Mechanism of Excited-State Proton Transfer

Unraveling the Detailed Mechanism of Excited-State Proton Transfer

Excited-state proton transfer of 4-hydroxyl-1, 8-naphthalimide derivatives: A combined experimental and theoretical investigation

Theoretical Insights into the Excited State Hydrogen Bond and ESIPT Reaction for 2-Amino-3-(2’-Benzoxazolyl)Quinoline and 2-Amino-3-(2’-Benzothiazolyl)-Quinoline

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