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proton transfer Isomerization of Pyrazole in the Ground State:σ vs π Mechanism and Water Assisting Effect

Chinese Journal of Structural Chemistry 2008年第12期27卷 1475-1486页

作者：李志强步宇翔赵显 Institute of Theoretical Chemistry and State Key Laboratory of Crystal Materials Shandong University

The proton transfer isomerization of pyrazole and the water assisting effect by looping 1 to 4 water molecules on the singlet state potential energy surface have been investigated by using hybrid density functional theory method （B3PW91） with a 6-311＋＋G^＊＊ basis set. Two mechanisms were proposed to explain the mono- and multi-water assisting effects, respectively. The reactants and products of all groups have been characterized on their potential energy surfaces. For the isomerizafion of monomolecule pyrazole, the isomeriz＇ation energy barrier is 46.4 kcal·mol^-1. For the monohydration assisting mechanism, the reactant complex is connected to the product complex via two saddle points. The corresponding isomerization barriers are 46.7and 23.0 kcal·mol^-1, respectively. As to the multihydration assisting mechanism, the isomerization barriers are 12.0, 10.9 and 13.14 kcal·mol^-1 accordingly, when the number of water molecules is 2, 3 and 4, respectively. The multihydration assisting isomerization can occur in water-dominated environments, for example, in the organism, and thereby is crucial to energy transference. The deproton and dehydrogen energies of monomolecule pyrazole and various hydrated pyrazoles were calculated and then found much bigger than the isomerization barriers of their relative complexes, suggesting the impossibility of deprotonation or dehydrogenation. The isomerization of pyrazole is a proton-coupling-electron-migration process, but two different mechanisms are noticed, viz. σ- and π-type mechanisms. The π-bond of pyrazole participates in isomerization in the π-type mechanism, whereas only o-electron takes part in isomerization in the σ-type mechanism.

关键词： pyrazole proton transfer σ/π mechanism DFT calculations water-assisting isomerization

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proton transfer across conducting polypyrrole membrane separated by two electrolyte solutions

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Chinese Journal of Chemistry 1997年第5期15卷 410-416页

作者： Wang, HM Yu, ZM Wang, EK Chinese Acad Sci Changchun Inst Appl Chem Electroanalyt Chem Lab Changchun 130022 Jilin Peoples R China

Electrochemical behavior of the transfer of H+ across polypyrrole membrane (PPM) was studied. The transfer process was quasi-reversible and mainly diffusion-controlled. PPM electropolymerized in water solution has better reversibility than that in CH3CN solution for the transfer of H+. The transfer process of H+ across the two kinds of PPM indicated that the PPM electrochemically polymerized was of asymmetry.

关键词： polypyrrole membrane proton transfer electrochemical polymerization

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Ultrafast proton transfer dynamics of 2-(2'-hydroxyphenyl)benzoxazole dye in different solvents

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Chinese Physics B 2022年第2期31卷 606-612页

作者： Simei Sun Song Zhang Jiao Song Xiaoshan Guo Chao Jiang Jingyu Sun Saiyu Wang Huangshi Key Laboratory of Photoelectric Technology and Materials College of Physics and Electronic ScienceHubei Normal UniversityHuangshi 435002China State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics Innovation Academy for Precision Measurement Science and TechnologyChinese Academy of SciencesWuhan 430071China Hubei Key Laboratory of Pollutant Analysis&Reuse Technology College of Chemistry and Chemical EngineeringHubei Normal UniversityHuangshi 435002China

The excited-state intramolecular proton transfer of 2-(2-hydroxyphenyl)benzoxazole dye in different solvents is investigated using ultrafast femtosecond transient absorption spectroscopy combined with quantum chemical *** conversion from the syn-enol configuration to the keto configuration is proposed as the mechanism of excited-state intramolecular proton *** duration of excited-state intramolecular proton transfer is measured to range from 50 fs to 200 fs in different *** time is strongly dependent on the calculated energy gap between the N-S;and T-S;structures in the S;*** the proton transfer reaction coordinate,the vibrational relaxation process on the S;state potential surface is *** duration of the vibrational relaxation process is determined to be from8.7 ps to 35 ps dependent on the excess vibrational energy.

关键词： proton transfer vibrational relaxation femtosecond transient absorption spectroscopy quantum chemical calculations

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Silica-facilitated proton transfer for high-temperature proton-exchange membrane fuel cells

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Science China Chemistry 2021年第12期64卷 2203-2211页

作者： Gen Huang Yingying Li Shiqian Du Yujie Wu Ru Chen Jin Zhang Yi Cheng Shanfu Lu Li Tao Shuangyin Wang State Key Laboratory of Chemo/Bio-Sensing and Chemometrics College of Chemistry and Chemical Engineeringthe National Supercomputer Centers in ChangshaAdvanced Catalytic Engineering Research Center of the Ministry of EducationHunan UniversityChangsha410082China Department of Environmental Engineering School of Metallurgy and EnvironmentCentral South UniversityChangsha410083China Beijing Key Laboratory of Bio-inspired Energy Materials and Devices School of Space and EnvironmentBeihang UniversityBeijing100191China

High-temperature proton-exchange membrane fuel cells(HT-PEMFCs)have shown a broad prospect of applications due to the enhanced reaction kinetics and simplified supporting ***,the proton conductor,phosphoric acid,tends to poison the active sites of Pt,resulting in high Pt ***,Pt nanoparticles anchored on SiO_(2)-modified carbon nanotubes(CNT@SiO_(2)-Pt)are prepared as high-performance cathode catalysts for *** SiO_(2)in CNT@SiO_(2)-Pt can induce the adsorption of phosphoric acid transferring from Pt active sites in the catalytic layer,avoiding the poisoning of the Pt,and the phosphate fixed by SiO_(2)provide a high-speed proton conduction highway for oxygen reduction ***,The CNT@SiO_(2)-Pt cathode achieve superior power density of 765 mW cm^(−2)(160℃)and 1,061 mW cm^(−2)(220℃)due to the rapid proton-coupled electron process and outstanding stability in *** result provides a new road to resolve the phosphate poisoning for the commercialization of HT-PEMFCs.

关键词： high-temperature proton exchange membrane fuel cell electrocatalyst proton transfer silica phosphoric acid

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Concerted versus stepwise mechanisms of cyclic proton transfer:Experiments, simulations, and current challenges

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Chinese Physics B 2023年第1期32卷 36-50页

作者：程奕涵朱禹丞李新征方为 State Key Laboratory for Artificial Microstructure and Mesoscopic Physics Frontier Science Center for Nano-optoelectronics and School of PhysicsPeking UniversityBeijing 100871China Interdisciplinary Institute of Light-Element Quantum Materials and Research Center for Light-Element Advanced Materials Peking UniversityBeijing 100871China Peking University Yangtze Delta Institute of Optoelectronics Nantong 226010China Collaborative Innovation Center of Quantum Matter Peking UniversityBeijing 100871China Department of Chemistry Fudan UniversityShanghai 200438China State Key Laboratory of Molecular Reaction Dynamics and Center for Theoretical Computational Chemistry Dalian Institute of Chemical PhysicsChinese Academy of SciencesDalian 116023China

proton transfer(PT) is a process of fundamental importance in hydrogen(H)-bonded systems. At cryogenic or moderate temperatures, pronounced quantum tunneling may happen due to the light mass of H. Single PT processes have been extensively studied. However, for PT involving multiple protons, our understanding remains in its infancy stage due to the complicated interplay between the high-dimensional nature of the process and the quantum nature of tunneling. Cyclic H-bonded systems are typical examples of this, where PT can happen separately via a “stepwise” mechanism or collectively via a “concerted” mechanism. In the first scenario, some protons hop first, typically resulting in metastable intermediate states(ISs) and the reaction pathway passes through multiple transition states. Whilst in the concerted mechanism, all protons move simultaneously, resulting in only one barrier along the path. Here, we review previous experimental and theoretical studies probing quantum tunneling in several representative systems for cyclic PT, with more focus on recent theoretical findings with path-integral based methods. For gas-phase porphyrin and porphycene, as well as porphycene on a metal surface, theoretical predictions are consistent with experimental observations, and enhance our understanding of the processes. Yet, discrepancies in the PT kinetic isotope effects between experiment and theory appear in two systems,most noticeably in water tetramer adsorbed on NaCl(001) surface, and also hinted in porphycene adsorbed on Ag(110)surface. In ice Ih, controversy surrounding concerted PT remains even between experiments. Despite of the recent progress in both theoretical methods and experimental techniques, multiple PT processes in cyclic H-bonded systems remain to be mysterious.

关键词： quantum tunneling proton transfer hydrogen bonding

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Theoretical Studies on the Hydrogen Bond transfer and proton transfer between Anamorphoses of the Dihydrated Glycine Complex

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Chinese Journal of Structural Chemistry 2007年第5期26卷 580-586页

作者： WANG Ke-Cheng MENG Xiang-Jun SHI Jin LI Bing-Huan Department of Chemistry Tangshan Teacher＇s College Tangshan 063000 China

The conversion between anamorphoses of the dihydrated glycine complex was studied by means of B3LYP/6-31＋＋G^＊＊. It was found that proton transfer was accompanied by hydrogen bond transfer in the process of conversion between different kinds of anamorphoses. With proton transfer, the electrostatic action was notably increased and the hydrogen-bonding action was evidently strengthened when the dihydrated neutral glycine complex converts into dihydrated zwitterionic glycine complex. The activation energy required for hydrogen bond transfer between dihydrated neutral glycine complexes is very low （6.32 kJ·mol^-1）; however, the hydrogen bond transfer between dihydrated zwitterionic glycine complexes is rather difficult with the required activation energy of 13.52 kJ·mol^-1 due to the relatively strong electrostatic action. The activation energy required by proton transfer is at least 27.33 kJ·mol^-1, higher than that needed for hydrogen bond transfer. The activation energy for either hydrogen bond transfer or proton transfer is in the bond-energy scope of medium-strong hydrogen bond, so the four kinds of anamorphoses of the dihydrated glycine complex could convert mutually.

关键词： intermolecular interaction B3LYP glycine,hydrogen bond transfer proton transfer

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Pattern recognition and data mining software based on artificial neural networks applied to proton transfer in aqueous environments

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Chinese Physics B 2014年第4期23卷 410-421页

作者： Amani Tahat Jordi Marti Ali Khwaldeh Kaher Tahat Department of Physics and Nuclear Engineering Technical University of Catalonia-Barcelona Tech B4-B5North Campus UPC08034 Barcelona Catalonia Spain Department of Computer Engineering Faculty of Engineering Philadelphia University Department of Graduate Business Studies Waterford Institute of TechnologyMain Campus Cork RoadWaterford Ireland

In computational physics proton transfer phenomena could be viewed as pattern classification problems based on a set of input features allowing classification of the proton motion into two categories： transfer ＇occurred＇ and transfer ＇not occurred＇. The goal of this paper is to evaluate the use of artificial neural networks in the classification of proton transfer events, based on the feed-forward back propagation neural network, used as a classifier to distinguish between the two transfer cases. In this paper, we use a new developed data mining and pattern recognition tool for automating, controlling, and drawing charts of the output data of an Empirical Valence Bond existing code. The study analyzes the need for pattern recognition in aqueous proton transfer processes and how the learning approach in error back propagation （multilayer perceptron algorithms） could be satisfactorily employed in the present case. We present a tool for pattern recognition and validate the code including a real physical case study. The results of applying the artificial neural networks methodology to crowd patterns based upon selected physical properties （e.g., temperature, density） show the abilities of the network to learn proton transfer patterns corresponding to properties of the aqueous environments, which is in turn proved to be fully compatible with previous proton transfer studies.

关键词： pattern recognition proton transfer chart pattern data mining artificial neural network empiricalvalence bond

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Hybrid Copolymerization via the Combination of proton transfer and Ring-opening Polymerization

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Chinese Journal of Polymer Science 2020年第3期38卷 231-239,I0005页

作者： Hong-Jun Yang Chen-Qiong Chai Yong-Kang Zuo Jin-Feng Huang Yi-Ye Song Li Jiang Wen-Yan Huang Qi-Min Jiang Xiao-Qiang Xue Bi-Biao Jiang China Jiangsu Key Laboratory of Environmentally Friendly Polymeric Materials School of Materials Science and EngineeringJiangsu Collaborative Innovation Centre of Photovoltaic Science and EngineeringChangzhou UniversityChangzhou 213164China Changzhou University Huaide College Jingjiang 214500China key Laboratory of Polymer Processing Engineering of Ministry of Education(South China University of Technology) Guangzhou 510000China

Phosphazene base,t-BuP2,was employed to catalyze the proton transfer polymerization(PTP)of 2-hydroxyethyl acrylate(HEA),and PTP was further combined with ring-opening polymerization(ROP)to exploit a new type of hybrid *** studies on homopolymerization showed that t-BuP2 was a particularly efficient catalyst for the polymerization of HEA at room temperature,giving an excellent monomer *** the polymerization,transesterification reactions were unavoidable,which increased the randomness in the structures of the resulting *** studies on copolymerization showed that t-BuP2 could simultaneously catalyze the hybrid copolymerization via the combination of PTP and ROP at 25°*** copolymerization,HEA not only provided hydroxyl groups to initiate the ROP ofε-caprolactone(CL)but also participated in the polymerization as a monomer for *** copolymer composition was approximately equal to the feed ratio,demonstrating the possibility to adjust the polymeric structure by simply changing the monomer feed *** copolymerization reaction provides a simple method for synthesizing degradable functional copolymers from commercially available ***,it is important not only in polymer chemistry but also in environmental and biomedical engineering.

关键词： Hybrid copolymerization proton transfer Ring-opening polymerization 2-Hydroxyethyl acrylate

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Chirality recognition in concerted proton transfer process for prismatic water clusters

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Nano Research 2016年第9期9卷 2782-2795页

作者： Bo Wang Wanrun Jiang Yang Gao Boon K.Teo Zhigang Wang Institute of Atomic and Molecular Physics Jilin UniversityChangchun 130012China Jilin Provincial Key Laboratory of Applied Atomic and Molecular Spectroscopy(Jilin University) Changchun 130012China College of Chemistry and Molecular Engineering Peking UniversityBeijing 100871China College of Chemistry and Chemical Engineering Xiamen UniversityXiamen 361005China Beijing Computational Science Research Center Beijing 100084China

proton transfer and chiral conversion via hydrogen bonds (HBs) are important processes in applications such as chiral recognition, enzymatic catalysis, and drug preparation. Herein, we investigate the chiral conversion and interlayer recognition, via concerted intralayer proton transfer (CIPT) processes, of small prismatic water clusters, in the form of bilayer n−membered water rings (BnWRs, n = 4, 5, 6). Density functional theory (DFT) calculations show that despite the small energy variations between the initial and final states of the clusters of less than 0.3 kcal·mol−1, the vibrational circular dichroism (VCD) spectrum provides clear chiral recognition peaks in the range of 3,000 to 3,500 cm−1. The vibrational modes in this region correspond to stretching of intralayer HBs, which produces strong signals in the infrared (IR) and Raman spectra. The electronic circular dichroism (ECD) spectrum also reveals obvious chiroptical characteristics. The molecular orbitals involved in the interlayer interaction are dominated by O 2p atomic orbitals; the energy of these orbitals increased by up to 0.1 eV as a result of the CIPT processes, indicating corresponding recognition between monolayer water clusters. In addition, isotopic substitution by deuterium in the BnWRs results in characteristic peaks in the VCD spectra that can be used as fingerprints in the identification of the chiral structures. Our findings provide new insights into the mechanism of chiral recognition in small prismatic water clusters at the atomic level as well as incentives for future experimental studies. [Figure not available: see fulltext.] © 2016, Tsinghua University Press and Springer-Verlag Berlin Heidelberg.

关键词： water cluster chirality proton transfer circular dichroism spectrum density functional theory calculation

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Theoretical Studies on proton transfer Reactions of 8-Hydroxyquinoline Monomers and Dimers

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Chinese Journal of Chemistry 2006年第6期24卷 724-730页

作者：赵继阳周子彦苏忠民谢玉忠孙光延吴学 Department of Chemistry College of Science Yanbian University Yanji Jilin 133002 China Institute of Functional Material Chemistry Faculty of Chemistry Northeast Normal University Changchun Jilin 130024 China Key Laboratory of Natural Resources of the Changbai Mountain and Functional Molecules Ministry of Education Yanbian University Yanji Jilin 133002 China

Density functional theory （DFT） of quantum chemistry method was employed to investigate proton transfer reactions of 8-hydroxyquinoline （8-HQ） monomers and dimers. By studying the potential energy curves of the isomerization, the most possible reaction pathway was found. The total energy of 8-hydroxyquinoline was lower than that of quinolin-8（1H）-one, whereas the order was reversed in dimers. The findings explained the contrary experimental phenomena. The minimum reaction barrier of intramolecular proton transfer was 47.3 kJ/mol while that in dimer was only 25.7 kJ/mol. Hence it is obvious that proton transfer reactions of 8-HQ monomer have a considerable rate but it is easier to proceed for 8-HQ dimer than monomers. It implied that the hydrogen bond played an important role in depressing the activation energy of reaction. The mechanism of the tautomerization was discussed on the basis of theoretical results.

关键词： 8-hydroxyquinoline proton transfer tautomerization density functional theory transition state

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