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Asatryan R, Hudzik J, Swihart M. Intramolecular Catalytic Hydrogen Atom Transfer (CHAT). J Phys Chem A 2024; 128:2169-2190. [PMID: 38451855 DOI: 10.1021/acs.jpca.3c06794] [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
Intramolecular catalysis (IntraCat) is the acceleration of a process at one site of a molecule catalyzed by a functional group in the same molecule; an external agent such as a solvent typically facilitates it. Here, we report a general first-principles-based IntraCat mechanism, which strictly occurs within a single molecule with no coreagent being involved─we call it intramolecular catalytic transfer of hydrogen atoms (CHAT). A reactive part of a molecule (chat catalyst moiety or chat agent, represented by -OOH, -COOH, -SH, -CH2OH, -HPO4, or another bifunctional H-donor/acceptor group) catalyzes an interconversion process, such as keto-enol or amino-imino tautomerization, and cyclization in the same molecule, while being regenerated in the process. It can thus be regarded as an intramolecular version of the intermolecular H atom transfer processes mediated by an external molecular catalyst, e.g., dihydrogen, water, or a carboxylic acid. Earlier, we proposed a general mechanistic systematization of intermolecular processes, illustrated in the simplest case of the H2-mediated reactions classified as dihydrogen catalysis [Asatryan, R.; et al. Catal. Rev.: Sci. Eng., 2014, 56, 403-475]. Following this systematization, the CHAT catalysis belongs to the category of relay transfer of H atoms, albeit in an intramolecular manner. A broader class of intramolecular processes includes all types of H-transfer reactions stimulated by an H-migration, which we call self-catalyzed H atom transfer (SC-HAT). The CHAT mechanism comprises a subset of SC-HAT in which the catalytic moiety is regenerated (i.e., acts as a true catalyst and not a reagent). We provide several characteristic examples of CHAT mechanism based on detailed analysis of the corresponding potential energy surfaces. All such cases showed a dramatically reduced activation barrier relative to the corresponding uncatalyzed H-transfer reactions. For example, we show that CHAT can facilitate long-range H-migration in larger molecules and can occur multiple times in one molecule with multiple interconverting groups. It also facilitates amino-imino tautomerization of unsaturated GABA-analogues and peptides, as well as intramolecular cyclization processes to form heterocycles, e.g., oxygenated rings. CHAT pathways may also explain the pH-dependent increase of mutarotation rate of glucose-6-phosphate demonstrated in pioneering experiments that introduced the classical IntraCat concept. In addition, we identify a ground electronic state CHAT pathway as an alternative to the UV-promoted long-range molecular crane keto-enol conversion with a remarkably low activation energy. To initially assess the possible impact of the new keto-enol conversion pathway on combustion of n-alkanes, we present a detailed kinetic analysis of isomerization and decomposition of pentane-2,4-ketohydroperoxide (2,4-KHP). The results are compared with key alternative reactions, including direct dissociation and Korcek channels (for which a new alkyl group migration channel is also identified), revealing the competitiveness of the CHAT pathway across a range of conditions. Taken together, this work provides insight into a general class of reaction pathways that has not previously being systematically considered and that may occur in a broad range of contexts from combustion to atmospheric chemistry to biochemistry.
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Affiliation(s)
- Rubik Asatryan
- Department of Chemical and Biological Engineering, and Center for Hybrid Rocket Exascale Simulation Technology (CHREST), University at Buffalo, The State University of New York, Buffalo, New York 14260, United States
| | - Jason Hudzik
- Department of Chemical and Biological Engineering, and Center for Hybrid Rocket Exascale Simulation Technology (CHREST), University at Buffalo, The State University of New York, Buffalo, New York 14260, United States
| | - Mark Swihart
- Department of Chemical and Biological Engineering, and Center for Hybrid Rocket Exascale Simulation Technology (CHREST), University at Buffalo, The State University of New York, Buffalo, New York 14260, United States
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Eun HJ, Ishiuchi SI, Yoo IT, Heo J, Park JW, Fujii M, Kim NJ. Cryogenic Ion Spectroscopy of Protonated and Sodiated Methyladenine Derivatives. J Phys Chem A 2023; 127:2472-2480. [PMID: 36895090 DOI: 10.1021/acs.jpca.2c09083] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/11/2023]
Abstract
Ultraviolet photodissociation (UVPD) spectra of protonated 9-methyladenine (H+9MA), protonated 7-methyl adenine (H+7MA), protonated 3-methyladenine (H+3MA), and sodiated 7-methyladenine (Na+7MA) near the origin bands of the S0-S1 transition were obtained using cryogenic ion spectroscopy. The UV-UV hole burning, infrared (IR) ion-dip, and IR-UV double resonance spectra showed that all the ions were present as single isomers in a cryogenic ion trap. The UVPD spectrum of H+9MA exhibited only a broad absorption band, whereas the spectra of H+7MA, H+3MA, and Na+7MA displayed moderately or well-resolved vibronic bands. Potential energy profiles were computed to understand the reason for the different bandwidths of the vibronic bands in the spectra. The broadening of the bands was correlated with the slopes between the Franck-Condon point and the conical intersection between the S1 and S0 states in the potential energy profiles, thus reflecting the deactivation rates in the S1 state.
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Affiliation(s)
- Han Jun Eun
- Gas Metrology Group, Division of Chemical and Biological Metrology, Korea Research Institute of Standards and Science (KRISS), Daejeon 34113, Korea
| | - Shun-Ichi Ishiuchi
- Department of Chemistry, Tokyo Institute of Technology, Ookayama 2-12-1, Tokyo 152-8550, Japan
| | - Il Tae Yoo
- Department of Chemistry, Chungbuk National University, Chungbuk 28644, Korea
| | - Jiyoung Heo
- Department of Green Chemical Engineering, Sangmyung University, Chungnam 31066, Korea
| | - Jae Woo Park
- Department of Chemistry, Chungbuk National University, Chungbuk 28644, Korea
| | - Masaaki Fujii
- Laboratory for Chemistry and Life Science, Tokyo Institute of Technology, Nagatsuta-cho, Yokohama 226-8503, Japan
| | - Nam Joon Kim
- Department of Chemistry, Chungbuk National University, Chungbuk 28644, Korea
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Zhu H, Gong F, Ma P, Qian Y, He L, Chen L, Qin X, Xu L. Protein-activated and FRET enhanced excited-state intermolecular proton transfer fluorescent probes for high-resolution imaging of cilia and tunneling nanotubes in live cells. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2023; 288:122142. [PMID: 36446173 DOI: 10.1016/j.saa.2022.122142] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/06/2022] [Revised: 11/13/2022] [Accepted: 11/20/2022] [Indexed: 06/16/2023]
Abstract
Excited-state intermolecular proton transfer (inter-ESPT) fluorescent probes responsive to specific bioactive molecules should be greatly promising for protein sensing, DNA mutation simulating and cellular process regulating. However, the inter-ESPT molecules are recessive ESPT fluorophores, which need the assistance of other molecules with both hydrogen-bond accepting and donating abilities to turn on the tautomeric fluorescence. Valid design strategies to create powerful inter-ESPT fluorescent probes are poorly developed, particularly for proteins as targets. We recently reported a unique supramolecular strategy to trigger the inter-ESPT process based on the probe-protein recognition by H-bonding and to image protein-based subcellular structures in live cells. Herein, we found that our inter-ESPT probes (inter-ESPT-01) bearing a 2-amino-3-cyanopyridine scaffold can anchor proteins and light up the "invisible" ESPT state, so as to image the proteins or the protein-based subcellular organelles. More importantly, the inter-ESPT emission of inter-ESPT-01 can be significantly enhanced by the FRET process between amino and imino tautomers, endowing the inter-ESPT-01 probes with super-bright tautomeric fluorescence. The expressed proteins Ecallantide and MarTX were selected as the models to light up the inter-ESPT fluorescence of the probes and revealed that the inter-ESPT process can be triggered by the specific probe-protein recognition events. In the use of the super-bright inter-ESPT fluorescence, not only the proteins, but also the protein-based cilia and tunneling nanotubes (TNTs) can be specifically visualized in living cancer cells. Furthermore, such recognition-driven strategy allows us to construct a unique inter-ESPT probe to track and image specific endogenous proteins in live cells, highlighting the potential of inter-ESPT fluorogens as novel intelligent biomaterials.
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Affiliation(s)
- Hanming Zhu
- College of Chemistry and Chemical Engineering, Changsha University of Science and Technology, Changsha 410114, PR China
| | - Fuchun Gong
- College of Chemistry and Chemical Engineering, Changsha University of Science and Technology, Changsha 410114, PR China.
| | - Pan Ma
- College of Chemistry and Chemical Engineering, Changsha University of Science and Technology, Changsha 410114, PR China
| | - You Qian
- College of Chemistry and Chemical Engineering, Changsha University of Science and Technology, Changsha 410114, PR China
| | - Lingzhi He
- College of Chemistry and Chemical Engineering, Changsha University of Science and Technology, Changsha 410114, PR China
| | - Lusen Chen
- College of Chemistry and Chemical Engineering, Changsha University of Science and Technology, Changsha 410114, PR China
| | - Xiaoling Qin
- College of Chemistry and Chemical Engineering, Changsha University of Science and Technology, Changsha 410114, PR China
| | - Lujie Xu
- College of Chemistry and Chemical Engineering, Changsha University of Science and Technology, Changsha 410114, PR China
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Yang WY, Yan CC, Wang XD, Liao LS. Recent progress on the excited-state multiple proton transfer process in organic molecules. Sci China Chem 2022. [DOI: 10.1007/s11426-022-1375-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/14/2022]
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Qian Y, Gong F, Li J, Ma P, Zhu H, He L, Xia J. A Solvent-Mediated Excited-State Intermolecular Proton Transfer Fluorescent Probe for Fe 3+ Sensing and Cell Imaging. Molecules 2022; 27:516. [PMID: 35056841 PMCID: PMC8778147 DOI: 10.3390/molecules27020516] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2021] [Revised: 01/02/2022] [Accepted: 01/06/2022] [Indexed: 12/05/2022] Open
Abstract
Constructing excited-state intermolecular proton transfer (ESIPT-e) fluorophores represents significant challenges due to the harsh requirement of bearing a proton donor-acceptor (D-A) system and their matching proton donating-accepting ability in the same molecule. Herein, we synthesized a new-type ESIPT-e fluorophor (2-APC) using the "four-component one-pot" reaction. By the installing of a cyano-group on pyridine scaffold, the proton donating ability of -NH2 was greatly enhanced, enabling 2-APC to undergo ESIPT-e process. Surprisingly, 2-APC exhibited dual-emissions in protic solvents ethanol and normal fluorescence in aprotic solvents, which is vastly different from that of conventional ESIPT-a dyes. The ESIPT emission can be obviously suppressed by Fe3+ due to the coordination reaction of Fe3+ with the A-D system in 2-APC. From this basis, a highly sensitive and selective method was established using 2-APC as a fluorescent probe, which offers the sensitive detection of Fe3+ ranging from 0 to 13 μM with the detection limit of 7.5 nM. The recovery study of spiked Fe3+ measured by the probe showed satisfactory results (97.2103.4%) with the reasonable RSD ranging from 3.1 to 3.8%. Moreover, 2-APC can also exhibit aggregation-induced effect in poor solvent or solid-state, eliciting strong red fluorescence. 2-APC was also applied to cell-imaging, exhibiting good cell-permeability, biocompatibility and color rendering. This multi-mode emission of 2-APC is significant departure from that of conventional extended p-conjugated systems and ESIPT dyes based on a flat and rigid molecular design. The "one-pot synthesis" strategy for the construction of ESIPT molecules pioneered a new route to achieve tricolor-emissive fluorophores.
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Affiliation(s)
- You Qian
- College of Chemistry and Chemical Engineering, Changsha University of Science and Technology, Changsha 410114, China; (Y.Q.); (P.M.); (H.Z.); (L.H.); (J.X.)
| | - Fuchun Gong
- College of Chemistry and Chemical Engineering, Changsha University of Science and Technology, Changsha 410114, China; (Y.Q.); (P.M.); (H.Z.); (L.H.); (J.X.)
| | - Jiguang Li
- Crop Research Institute, Hunan Academy of Agricultural Sciences, Changsha 410125, China;
| | - Pan Ma
- College of Chemistry and Chemical Engineering, Changsha University of Science and Technology, Changsha 410114, China; (Y.Q.); (P.M.); (H.Z.); (L.H.); (J.X.)
| | - Hanming Zhu
- College of Chemistry and Chemical Engineering, Changsha University of Science and Technology, Changsha 410114, China; (Y.Q.); (P.M.); (H.Z.); (L.H.); (J.X.)
| | - Lingzhi He
- College of Chemistry and Chemical Engineering, Changsha University of Science and Technology, Changsha 410114, China; (Y.Q.); (P.M.); (H.Z.); (L.H.); (J.X.)
| | - Jiaoyun Xia
- College of Chemistry and Chemical Engineering, Changsha University of Science and Technology, Changsha 410114, China; (Y.Q.); (P.M.); (H.Z.); (L.H.); (J.X.)
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Luminescent excited-state intramolecular proton-transfer dyes based on 4-functionalized 6,6'-dimethyl-3,3'-dihydroxy-2,2'-bipyridine (BP(OH)2-Rs); DFT simulation study. J Mol Graph Model 2021; 107:107948. [PMID: 34082341 DOI: 10.1016/j.jmgm.2021.107948] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2021] [Revised: 05/04/2021] [Accepted: 05/20/2021] [Indexed: 01/28/2023]
Abstract
The 4-functionalized 6,6'-dimethyl-3,3'-dihydroxy-2,2'-bipyridine dyes (BP(OH)2-Rs) have exhibited dienol and diketo emissions. The optimum geometrical structures for ground, singlet and triplet excited states are computed by DFT/B3LYP/6-31++G that showed the planarity of BP(OH)2-Rs structure. The emission spectra of the molecules are determined in the gas-phase at singlet and triplet excited states using CIS/6-31++G. The theoretical calculations are carried out for BP(OH)2-Rs to understand the impact of different substituents (R = -H (I), -Br (II), -TMS (III), -C2H (IV), -terpyridine (V) and -bodipy (diazaboraindacene) (VI)) on excited-state intramolecular proton transfer (ESIPT) in singlet and triplet excited states. Based on the calculations, the concerted diproton transfer proceeds in the triplet excited state, in which nπ* state has a significant participation in ESIPT. The spectral variation at ESIPT emission of BP(OH)2-Rs is influenced by the electron-acceptor ability of the substituents. The compound V revealed a higher spectral intensity compared to the others. From the comparison with the experimental data, the molecule V is almost planar agreed with the X-ray structure and trend variation of wavelengths. The molecule VI contains bodipy chromophore that excitation energy transfers completely from BP(OH)2 core to a bodipy substituent, leading to emission from the lowest-lying bodipy substituent, and consequently, ESIPT does not occur for this dye.
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7
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Zhang H, Liu S, Zhang C, Fan J, Lin L, Wang C, Song Y. The mechanism of the excited-state proton transfer of Salicylaldehyde azine and 2,2'-[1,4-Phenylenebis{(E)- nitrilomethylidyne}] bisphenol: Via single or double proton transfer. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2019; 223:117321. [PMID: 31277029 DOI: 10.1016/j.saa.2019.117321] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/22/2019] [Revised: 06/25/2019] [Accepted: 06/25/2019] [Indexed: 06/09/2023]
Abstract
The Salicylaldehyde azine (H2SA) and 2,2'-[1,4-Phenylenebis{(E)-nitrilomethylidyne}] bisphenol (H2SPA) with double proton transfer characteristics were synthesized recently (Phys. Chem. Chem. Phys., 2018, 20, 23,762). However, the detailed theoretical interpretation of proton transfer (PT) mechanism is inadequate. In the present work, density functional theory (DFT) and time-density functional theory (TDDFT) are employed to study the proton transfer mechanism of H2SA and H2SPA in detail. Bond parameters, infrared (IR) spectra and frontier molecular orbitals (FMOs) calculated by PBE0/TZVP method indicate the strength of hydrogen bond is enhanced in S1 state, which can be visualized by the reduced density gradient (RDG) analysis. The potential energy surfaces (PESs) of H2SA and H2SPA are also constructed. The small barriers indicate that both the single proton transfer and double proton transfer of H2SA and H2SPA are more likely to occur in the S1 state. In addition, the properties of H2SA and H2SPA after chelation with Li+ have also been theoretically characterized. According to the calculated fluorescence spectra of compounds (H2SA-Li+ and H2SPA-Li+), it was found that only the planar structure of H2SA-Li+ can form metallogel, which verified the experimental results.
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Affiliation(s)
- Hui Zhang
- Shandong Province Key Laboratory of Medical Physics and Image Processing Technology, School of Physics and Electronics, Shandong Normal University, Jinan 250358, China
| | - Songsong Liu
- Shandong Province Key Laboratory of Medical Physics and Image Processing Technology, School of Physics and Electronics, Shandong Normal University, Jinan 250358, China
| | - Changzhe Zhang
- Shandong Province Key Laboratory of Medical Physics and Image Processing Technology, School of Physics and Electronics, Shandong Normal University, Jinan 250358, China
| | - Jianzhong Fan
- Shandong Province Key Laboratory of Medical Physics and Image Processing Technology, School of Physics and Electronics, Shandong Normal University, Jinan 250358, China
| | - Lili Lin
- Shandong Province Key Laboratory of Medical Physics and Image Processing Technology, School of Physics and Electronics, Shandong Normal University, Jinan 250358, China
| | - Chuankui Wang
- Shandong Province Key Laboratory of Medical Physics and Image Processing Technology, School of Physics and Electronics, Shandong Normal University, Jinan 250358, China
| | - Yuzhi Song
- Shandong Province Key Laboratory of Medical Physics and Image Processing Technology, School of Physics and Electronics, Shandong Normal University, Jinan 250358, China.
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Kumar A, Iyengar SS. Fragment-Based Electronic Structure for Potential Energy Surfaces Using a Superposition of Fragmentation Topologies. J Chem Theory Comput 2019; 15:5769-5786. [DOI: 10.1021/acs.jctc.9b00608] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Affiliation(s)
- Anup Kumar
- Department of Chemistry and Department of Physics, Indiana University, 800 East Kirkwood Avenue, Bloomington, Indiana-47405, United States
| | - Srinivasan S. Iyengar
- Department of Chemistry and Department of Physics, Indiana University, 800 East Kirkwood Avenue, Bloomington, Indiana-47405, United States
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Tan H, Kong P, Liu M, Gu X, Zheng Z. Enhanced photocatalytic hydrogen production from aqueous-phase methanol reforming over cyano-carboxylic bifunctionally-modified carbon nitride. Chem Commun (Camb) 2019; 55:12503-12506. [DOI: 10.1039/c9cc06600d] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Polymeric carbon nitride is a promising candidate for metal-free photocatalysis, but it is hampered by low activity due to poor carrier separation efficiency and lack of active sites.
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Affiliation(s)
- Hao Tan
- State Key Laboratory of Coal Conversion
- Institute of Coal Chemistry
- Chinese Academy of Sciences
- Taiyuan 030001
- China
| | - Peng Kong
- State Key Laboratory of Coal Conversion
- Institute of Coal Chemistry
- Chinese Academy of Sciences
- Taiyuan 030001
- China
| | - Meixian Liu
- State Key Laboratory of Coal Conversion
- Institute of Coal Chemistry
- Chinese Academy of Sciences
- Taiyuan 030001
- China
| | - Xianmo Gu
- State Key Laboratory of Coal Conversion
- Institute of Coal Chemistry
- Chinese Academy of Sciences
- Taiyuan 030001
- China
| | - Zhanfeng Zheng
- State Key Laboratory of Coal Conversion
- Institute of Coal Chemistry
- Chinese Academy of Sciences
- Taiyuan 030001
- China
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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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Beniwal V, Kumar A, Pal H. Excited state intramolecular proton transfer in 1,8-Dihydroxy-9,10-anthraquinone dye: Revealing microstructures in [CnmIm][NTf2] and [CnmIm][BF4] series of ionic liquid solvents. J Photochem Photobiol A Chem 2018. [DOI: 10.1016/j.jphotochem.2017.09.073] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
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12
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Fatima N, Reddy BS, Gowravaram S, Yadav J, Kadari S, Putta CS. Synthesis and biological evaluation of 1-amino isochromans from 2-bromoethyl benzaldehyde and amines in acid medium. Bioorg Med Chem Lett 2018; 28:196-201. [DOI: 10.1016/j.bmcl.2017.11.020] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2017] [Revised: 10/13/2017] [Accepted: 11/09/2017] [Indexed: 01/17/2023]
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Iwata K, Terazima M, Masuhara H. Novel physical chemistry approaches in biophysical researches with advanced application of lasers: Detection and manipulation. Biochim Biophys Acta Gen Subj 2017; 1862:335-357. [PMID: 29108958 DOI: 10.1016/j.bbagen.2017.11.003] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2017] [Revised: 10/30/2017] [Accepted: 11/01/2017] [Indexed: 10/18/2022]
Abstract
Novel methodologies utilizing pulsed or intense CW irradiation obtained from lasers have a major impact on biological sciences. In this article, recent development in biophysical researches fully utilizing the laser irradiation is described for three topics, time-resolved fluorescence spectroscopy, time-resolved thermodynamics, and manipulation of the biological assemblies by intense laser irradiation. First, experimental techniques for time-resolved fluorescence spectroscopy are concisely explained in Section 2. As an example of the recent application of time-resolved fluorescence spectroscopy to biological systems, evaluation of the viscosity of lipid bilayer membranes is described. The results of the spectroscopic experiments strongly suggest the presence of heterogeneous membrane structure with two different viscosity values in liposomes formed by a single phospholipid. Section 3 covers the time-resolved thermodynamics. Thermodynamical properties are important to characterize biomolecules. However, measurement of these quantities for short-lived intermediate species has been impossible by traditional thermodynamical techniques. Recently, development of a spectroscopic method based on the transient grating method enables us to measure these quantities and also to elucidate reaction kinetics which cannot be detected by other spectroscopic methods. The principle of the measurements and applications to some protein reactions are reviewed. Manipulation and fabrication of supramolecues, amino acids, proteins, and living cells by intense laser irradiation are described in Section 4. Unconventional assembly, crystallization and growth, amyloid fibril formation, and living cell manipulation are achieved by CW laser trapping and femtosecond laser-induced cavitation bubbling. Their spatio-temporal controllability is opening a new avenue in the relevant molecular and bioscience research fields. This article is part of a Special Issue entitled "Biophysical Exploration of Dynamical Ordering of Biomolecular Systems" edited by Dr. Koichi Kato.
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Affiliation(s)
- Koichi Iwata
- Department of Chemistry, Faculty of Science, Gakushuin University, 1-5-1 Mejiro, Toshima-ku, Tokyo 171-8588, Japan.
| | - Masahide Terazima
- Department of Chemistry, Graduate School of Science, Kyoto University, Sakyo-ku, Kyoto 606-8502, Japan.
| | - Hiroshi Masuhara
- Department of Applied Chemistry, National Chiao Tung University, 1001 Ta Hsueh Rd., Hsinchu 30010, Taiwan.
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Yang D, Yang G, Zhao J, Song N, Zheng R, Wang Y. Solvent controlling excited state proton transfer reaction in quinoline/isoquinoline-pyrazole isomer QP-I: A theoretical study. J PHYS ORG CHEM 2017. [DOI: 10.1002/poc.3729] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- Dapeng Yang
- College of Mathematics and Information Science; North China University of Water Resources and Electric Power; Zhengzhou China
- Department of Basic Science; Jiaozuo University; Jiaozuo China
| | - Guang Yang
- Department of Basic Science; Jiaozuo University; Jiaozuo China
| | - Jinfeng Zhao
- State Key Laboratory of Molecular Reaction Dynamics, Theoretical and Computational Chemistry, Dalian Institute of Chemical Physics; Chinese Academy of Sciences; Dalian China
| | - Nahong Song
- College of Computer and Information Engineering; Henan University of Economics and Law; Zhengzhou China
| | - Rui Zheng
- College of Mathematics and Information Science; North China University of Water Resources and Electric Power; Zhengzhou China
| | - Yusheng Wang
- College of Mathematics and Information Science; North China University of Water Resources and Electric Power; Zhengzhou China
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15
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Zhou Q, Du C, Yang L, Zhao M, Dai Y, Song P. Mechanism for the Excited-State Multiple Proton Transfer Process of Dihydroxyanthraquinone Chromophores. J Phys Chem A 2017; 121:4645-4651. [DOI: 10.1021/acs.jpca.7b04051] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Qiao Zhou
- College
of Physics, Liaoning University, Shenyang 110036, P. R. China
| | - Can Du
- College
of Physics, Liaoning University, Shenyang 110036, P. R. China
| | - Li Yang
- College
of Physics, Liaoning University, Shenyang 110036, P. R. China
| | - Meiyu Zhao
- School
of Chemistry and Chemical Engineering, Harbin Institute of Technology, Harbin 150080, P. R. China
| | - Yumei Dai
- Normal
College, Shenyang University, Shenyang 110044, P. R. China
| | - Peng Song
- College
of Physics, Liaoning University, Shenyang 110036, P. R. China
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16
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Yang D, Yang G, Zhao J, Zheng R, Wang Y, Lv J. A theoretical assignment on excited-state intramolecular proton transfer mechanism for quercetin. J PHYS ORG CHEM 2017. [DOI: 10.1002/poc.3684] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Affiliation(s)
- Dapeng Yang
- College of Mathematics and Information Science; North China University of Water Resources and Electric Power; Zhengzhou 450045 China
- State Key Laboratory of Molecular Reaction Dynamics, Theoretical and Computational Chemistry, Dalian Institute of Chemical Physics; Chinese Academy of Sciences; Dalian 116023 China
| | - Guang Yang
- Department of Basic Science; Jiaozuo University; Jiaozuo 454000 China
| | - Jinfeng Zhao
- State Key Laboratory of Molecular Reaction Dynamics, Theoretical and Computational Chemistry, Dalian Institute of Chemical Physics; Chinese Academy of Sciences; Dalian 116023 China
| | - Rui Zheng
- College of Mathematics and Information Science; North China University of Water Resources and Electric Power; Zhengzhou 450045 China
| | - Yusheng Wang
- College of Mathematics and Information Science; North China University of Water Resources and Electric Power; Zhengzhou 450045 China
| | - Jian Lv
- College of Mathematics and Information Science; North China University of Water Resources and Electric Power; Zhengzhou 450045 China
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17
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Yang D, Zheng R, Wang Y, Lv J. A Theoretical Investigation on Intramolecular Hydrogen Bond: The ESIPT Mechanism of dmahf Sensor. J CLUST SCI 2016. [DOI: 10.1007/s10876-016-1090-z] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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18
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Yang D, Li P, Zheng R, Wang Y, Lv J. A research on excited-state intramolecular proton-transfer mechanism of a new chemosensor. Theor Chem Acc 2016. [DOI: 10.1007/s00214-015-1802-8] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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19
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Rajkumar MA, NizamMohideen M, Xavier SSJ, Anbarasu S, Devarajan DPA. Crystal structure of 2-amino-5-nitro-pyridinium sulfamate. ACTA CRYSTALLOGRAPHICA SECTION E-CRYSTALLOGRAPHIC COMMUNICATIONS 2015; 71:231-3. [PMID: 25878827 PMCID: PMC4384627 DOI: 10.1107/s2056989015000365] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/15/2014] [Accepted: 01/08/2015] [Indexed: 11/23/2022]
Abstract
The title molecular salt, obtained by the reaction of sulfamic acid with 2-amino-5-nitropyridine, is the result of a proton transfer from sulfamic acid to the N atom of the pyridine ring. In the crystal, the cations and anions are linked by a number of N—H⋯O and N—H⋯N hydrogen bonds, forming sheets lying parallel to (100). The title molecular salt, C5H6N3O2+ ·H2NO3S−, was obtained from the reaction of sulfamic acid with 2-amino-5-nitropyridine. A proton transfer from sulfamic acid to the pyridine N atom occurred, resulting in the formation of a salt. As expected, this protonation leads to the widening of the C—N—C angle of the pyridine ring, to 122.9 (3)°, with the pyridinium ring being essentially planar (r.m.s. deviation = 0.025 Å). In the crystal, the ion pairs are joined by three N—H⋯O and one N—H⋯N hydrogen bonds in which the pyridinium N atom and the amino N atom act as donors, and are hydrogen bonded to the carboxylate O atoms and the N atom of the sulfamate anion, thus generating an R33(22) ring motif. These motifs are linked by further N—H⋯O hydrogen bonds enclosing R33(8) loops, forming sheets parallel to (100). The sheets are linked via weak C—H⋯O hydrogen bonds, forming a three-dimensional structure. The O atoms of the nitro group are disordered over two sets of sites with a refined occupancy ratio of 0.737 (19):0.263 (19).
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Affiliation(s)
- M Ambrose Rajkumar
- Physics Research Centre, Department of Physics, St. Xavier's College (Autonomous), Palayamkottai 627 002, Tamil Nadu, India
| | - M NizamMohideen
- Department of Physics, The New College (Autonomous), Chennai 600 014, Tamil Nadu, India
| | - S Stanly John Xavier
- Department of Chemistry, St. Xavier's College (Autonomous), Palayamkottai 627 002, Tamil Nadu, India
| | - S Anbarasu
- Physics Research Centre, Department of Physics, St. Xavier's College (Autonomous), Palayamkottai 627 002, Tamil Nadu, India
| | - Dr Prem Anand Devarajan
- Physics Research Centre, Department of Physics, St. Xavier's College (Autonomous), Palayamkottai 627 002, Tamil Nadu, India
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20
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Babu KSS, Dhavamurthy M, NizamMohideen M, Peramaiyan G, Mohan R. 2-Amino-6-methyl-pyridinium 4-methyl-benzene-sulfonate. Acta Crystallogr Sect E Struct Rep Online 2014; 70:o600-1. [PMID: 24860395 PMCID: PMC4011207 DOI: 10.1107/s1600536814008587] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2014] [Accepted: 04/15/2014] [Indexed: 11/10/2022]
Abstract
In the asymmetric unit of the title salt, C6H9N2+·C7H7O3S−, there are two independent 2-amino-6-methylpyridinium cations and two independent 4-methylbenzenesulfonate anions. Both cations are protonated at their pyridine N atoms and their geometries reveal amine–imine tautomerism. In the 4-methylbenzenesulfonate anions, the carboxylate groups are twisted out of the benzene ring planes by 88.4 (1) and 86.2 (2)°. In the crystal, the sulfonate O atoms of an anion interact with the protonated N atoms and the 2-amino groups of a cation via a pair of N—H⋯O hydrogen bonds, forming an R22(8) ring motif. These motifs are connected via N—H⋯O hydrogen bonds, forming chains running along the a-axis direction. Within the chains there are weak C—H⋯O hydrogen bonds present. In addition, aromatic π–π stacking interactions [centroid–centroid distances = 3.771 (2), 3.599 (2), 3.599 (2) and 3.497 (2) Å] involving neighbouring chains are also observed.
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Affiliation(s)
- K Syed Suresh Babu
- Department of Physics, Presidency College (Autonomous), Chennai 600 005, Tamil Nadu, India ; Department of Physics, The New College (Autonomous), Chennai 600 014, Tamil Nadu, India
| | - M Dhavamurthy
- Department of Physics, Presidency College (Autonomous), Chennai 600 005, Tamil Nadu, India
| | - M NizamMohideen
- Department of Physics, The New College (Autonomous), Chennai 600 014, Tamil Nadu, India
| | - G Peramaiyan
- Department of Physics, Presidency College (Autonomous), Chennai 600 005, Tamil Nadu, India
| | - R Mohan
- Department of Physics, Presidency College (Autonomous), Chennai 600 005, Tamil Nadu, India
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21
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Babu KSS, Peramaiyan G, NizamMohideen M, Mohan R. 2-Amino-6-methyl-pyridinium 2,2,2-tri-chloro-acetate. Acta Crystallogr Sect E Struct Rep Online 2014; 70:o391-2. [PMID: 24826114 PMCID: PMC3998557 DOI: 10.1107/s1600536814004553] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2014] [Accepted: 02/27/2014] [Indexed: 11/10/2022]
Abstract
In the asymmetric unit of the title molecular salt, C6H9N2+·C2Cl3O2−, there are two independent 2-amino-6-methylpyridinium cations and two independent trichloroacetate anions. The pyridine N atom of the 2-amino-6-methylpyridine molecule is protonated and the geometries of these cations reveal amine–imine tautomerism. Both protonated 2-amino-6-methylpyridinium cations are essentially planar [maximum deviations = 0.026 (2) and 0.012 (2) Å]. In the crystal, the protonated N atom and the 2-amino group of the cation are hydrogen bonded to the carboxylate O atoms of the anion via a pair of N—H⋯O hydrogen bonds, forming an R22(8) ring motif. These motifs are connected via N—H⋯O and C—H⋯O hydrogen bonds to form slabs parallel to (101).
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Affiliation(s)
- K Syed Suresh Babu
- Department of Physics, Presidency College (Autonomous), Chennai 600 005, Tamil Nadu, India ; Department of Physics, The New College (Autonomous), Chennai 600 014, Tamil Nadu, India
| | - G Peramaiyan
- Department of Physics, Presidency College (Autonomous), Chennai 600 005, Tamil Nadu, India
| | - M NizamMohideen
- Department of Physics, The New College (Autonomous), Chennai 600 014, Tamil Nadu, India
| | - R Mohan
- Department of Physics, Presidency College (Autonomous), Chennai 600 005, Tamil Nadu, India
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22
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Manna A, Sayed M, Kumar A, Pal H. Atypical Energetic and Kinetic Course of Excited-State Intramolecular Proton Transfer (ESIPT) in Room-Temperature Protic Ionic Liquids. J Phys Chem B 2014; 118:2487-98. [DOI: 10.1021/jp500281z] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Affiliation(s)
- Arpan Manna
- Physical and Material
Chemistry Division, National Chemical Laboratory, H. J. Bhabha Road, Pune 411 008, India
| | - Mhejabeen Sayed
- Radiation & Photochemistry Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400 085, India
| | - Anil Kumar
- Physical and Material
Chemistry Division, National Chemical Laboratory, H. J. Bhabha Road, Pune 411 008, India
| | - Haridas Pal
- Radiation & Photochemistry Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400 085, India
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23
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24
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Jana S, Dalapati S, Guchhait N. Functional group induced excited state intramolecular proton transfer process in 4-amino-2-methylsulfanyl-pyrimidine-5-carboxylic acid ethyl ester: a combined spectroscopic and density functional theory study. Photochem Photobiol Sci 2013; 12:1636-48. [DOI: 10.1039/c3pp50010a] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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25
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Eberhard J, Stoll I, Brockhinke R, Neumann B, Stammler HG, Riefer A, Rauls E, Schmidt WG, Mattay J. Structural variety of 5-fluoroarene-2-aminopyrimidine in comparison to 2-aminopyrimidine silver(i) coordination polymers: progress report and overview. CrystEngComm 2013. [DOI: 10.1039/c2ce26388b] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
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26
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Prabavathi N, Nilufer A, Krishnakumar V, Akilandeswari L. Spectroscopic, electronic structure and natural bond analysis of 2-aminopyrimidine and 4-aminopyrazolo[3,4-d]pyrimidine: a comparative study. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2012; 96:226-241. [PMID: 22683558 DOI: 10.1016/j.saa.2012.05.015] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/31/2012] [Revised: 04/23/2012] [Accepted: 05/03/2012] [Indexed: 06/01/2023]
Abstract
The FTIR and FT-Raman spectra of 2-aminopyrimidine (2-AP) and 4-aminopyrazolo[3,4-d]pyrimidine (4-APP) has been recorded in the region 4000-400 and 3500-100 cm(-1), respectively. The tautomeric stability, optimized geometry, frequency and intensity of the vibrational bands of 2-AP and 4-APP were obtained by the DFT level using 6-31G(d) and 6-31G(d,p) basis sets. The harmonic vibrational frequencies were calculated and the scaled values have been compared with experimental FTIR and FT-Raman spectra. A detailed interpretation of the infrared and Raman spectra of 2-AP and 4-APP are also reported based on total energy distribution (TED). The observed and the calculated frequencies are found to be in good agreement. The experimental spectra also coincide satisfactorily with those of theoretically simulated spectra. The (1)H and (13)C NMR spectra have been simulated using the gauge independent atomic orbital (GIAO) method. The theoretical UV-Vis spectrum of the compound using CIS method and the electronic properties, such as HOMO and LUMO energies, were performed by time-dependent DFT (TD-DFT) approach. The calculated HOMO and LUMO energies show that charge transfer occurs within molecule. The first order hyperpolarizability (β(0)) of these novel molecular system and related properties (β, α(0) and Δα) of 2-AP and 4-APP are calculated using DFT/6-31G(d) method on the finite-field approach. The Mulliken charges, the values of electric dipole moment (μ) of the molecule were computed using DFT calculations. The change in electron density (ED) in the σ(∗) antibonding orbitals and stabilization energies E(2) have been calculated by natural bond (NBO) analysis to give clear evidence of stabilization originating in the hyper conjugation of hydrogen-bonded interactions.
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Affiliation(s)
- N Prabavathi
- Department of Physics, Sri Sarada College for Women (Autonomous), Salem 636 016, India.
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27
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DFT studies on one-electron oxidation and one-electron reduction for 2- and 4-aminopyridines. J Mol Model 2012; 18:4367-80. [PMID: 22585356 PMCID: PMC3429776 DOI: 10.1007/s00894-012-1446-8] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2012] [Accepted: 04/23/2012] [Indexed: 11/28/2022]
Abstract
Quantum-chemical calculations {DFT(B3LYP)/6-311+G(d,p)} were performed for all possible tautomers (aromatic and nonaromatic) of neutral 2- and 4-aminopyridines and their oxidized and reduced forms. One-electron oxidation has no important effect on the tautomeric preference for 2-aminopyridine. The amine tautomer is favored. However, oxidation increases the stability of the imine NH tautomer, and its contribution in the tautomeric mixture cannot be neglected. In the case of 4-aminopyridine, one-electron oxidation increases the stability of both the amine and imine NH tautomers. Consequently, they possess very close energies. As major tautomers, they dictate the composition of the tautomeric mixture. The CH tautomers may be considered as very rare forms for both neutral and oxidized aminopyridines. A reverse situation takes place for the reduced forms of aminopyridines. One-electron reduction favors the C3 atom for the labile proton for both aminopyridines. This may partially explain the origin of the CH tautomers for the anionic states of nucleobases containing the exo NH2 group.
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28
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Yang Z, Chen G, Xu W, Fan Z. Tetra-kis(2-amino-6-methyl-pyridinium) hexa-chloridobismuthate(III) chloride monohydrate. Acta Crystallogr Sect E Struct Rep Online 2009; 65:m887. [PMID: 21583350 PMCID: PMC2977446 DOI: 10.1107/s1600536809025446] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2009] [Accepted: 07/01/2009] [Indexed: 11/10/2022]
Abstract
The asymmetric unit of the title compound, (C(6)H(9)N(2))(4)[BiCl(6)]Cl·H(2)O, contains four protonated 2-amino-6-methyl-pyridine (HAMP) cations and two-halves of two [BiCl(6)](3-) anions, together with one water mol-ecule and one chloride anion. The Bi(III) atoms are hexa-coordinated by Cl atoms, forming distorted octa-hedral geometries. In the crystal structure, intra-molecular O-H⋯Cl and N-H⋯Cl, and inter-molecular O-H⋯Cl and N-H⋯O inter-actions link the mol-ecules into a three-dimensional network.
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29
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4-(1-Alkylbenzimidazol-2-ylazo)-2-pyrazolin-5-ones: specific features of prototropic tautomerism. Russ Chem Bull 2009. [DOI: 10.1007/s11172-008-0194-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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30
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Morkovnik AS, Divaeva LN. Tautomerism of quinazolin-4-ones with 2,3-annulated hydrogenated 1,3-diazaheterocycles. Synchronous and asynchronous double proton transfer in cyclic hydrogen-bonded associates. Russ Chem Bull 2009. [DOI: 10.1007/s11172-009-0111-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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31
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Sumitomo K, Sasaki M, Yamaguchi Y. Acetic acid denaturing for RNA capillary polymer electrophoresis. Electrophoresis 2009; 30:1538-43. [DOI: 10.1002/elps.200800457] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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32
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Chai S, Zhao GJ, Song P, Yang SQ, Liu JY, Han KL. Reconsideration of the excited-state double proton transfer (ESDPT) in 2-aminopyridine/acid systems: role of the intermolecular hydrogen bonding in excited states. Phys Chem Chem Phys 2009; 11:4385-90. [PMID: 19458842 DOI: 10.1039/b816589k] [Citation(s) in RCA: 170] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Affiliation(s)
- Shuo Chai
- State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Science, Dalian, 116023, China
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33
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Sekiya H, Sakota K. Excited-state double-proton transfer in a model DNA base pair: Resolution for stepwise and concerted mechanism controversy in the 7-azaindole dimer revealed by frequency- and time-resolved spectroscopy. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY C-PHOTOCHEMISTRY REVIEWS 2008. [DOI: 10.1016/j.jphotochemrev.2008.04.001] [Citation(s) in RCA: 92] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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34
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Kitamura T, Okita M, Sasaki Y, Ishikawa H, Fujimoto A. Amino-imino tautomerization reaction of the 4-aminopyrimidine/acetic acid system. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2008; 69:350-60. [PMID: 17544320 DOI: 10.1016/j.saa.2007.04.006] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/19/2006] [Accepted: 04/12/2007] [Indexed: 05/15/2023]
Abstract
The amino-imino tautomerization of the 4-aminopyrimidine (4APM)/acetic acid (AcOH) system through dual hydrogen bonding in n-hexane at room temperature was investigated using UV absorption and fluorescence spectroscopies, fluorescence time-profile measurements, and molecular orbital calculations, with those of the imino-model compound of 3-methyl-4(1H)-pyrimidinimine (3M4PMI). From the experimental results, it was confirmed that the imino-tautomer was formed in the first excited singlet state (S1) state through the double-proton transfer of the dual hydrogen-bonded complex of 4APM with AcOH. The fluorescences of the free 4APM monomer (band maximum at 353nm), imino-tautomer (at 414nm), and 3M4PMI monomer (at 437nm) exhibit the single-exponential decays of 98, 73, and 19ps time constants, respectively. The shorter decay time of the imino-tautomer fluorescence compared with the free monomer one is suggestive of the low activation energy process in the S1 state. From the result of the shortest decay time of the 3M4PMI fluorescence, it can be deduced that 3M4PMI has a non-planar structure in the S1 state. The theoretical calculations on the S0 and S1 state double-proton transfer for the 4APM/AcOH dual hydrogen-bonded system were performed with the use of formic acid (FoOH) in place of AcOH for the sake of simplicity. Only one peak of transition state was resolved in the S0 and S1 states. The energy barrier for the S1 state double-proton transfer of the 4APM/FoOH complex-->3H-4(1H)-pyrimidinimine/FoOH tautomer was estimated to be approximately 2kJmol(-1) using the CIS/6-31G(d) methods. On the other hand, the energy barrier for the S0 state reverse proton transfer of the 3H-4(1H)-pyrimidinimine/FoOH tautomer-->4APM/FoOH complex was estimated to be almost zero kJmol(-1) at B3LYP/6-31G(d) level.
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Affiliation(s)
- Teruyoshi Kitamura
- Department of Environmental Materials Science, Tokyo Denki University, Kanda, Tokyo 101-8457, Japan
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35
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Sumitomo K, Yamaguchi Y. High performance RNA separation by in-capillary denaturing gel electrophoresis with carboxylic acid as RNA denaturant. ACTA ACUST UNITED AC 2008. [DOI: 10.2198/sbk.52.133] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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36
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Kitamura T, Mochida N, Okita M, Motohashi M, Ishikawa H, Fujimoto A. The hydrogen bonding and amino-imino tautomerization of the alkoxy-aminopyridines and amino-methoxypyrimidines with acetic acid The effects of the methoxy group. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2007; 68:979-91. [PMID: 17336582 DOI: 10.1016/j.saa.2007.01.011] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/23/2006] [Accepted: 01/13/2007] [Indexed: 05/14/2023]
Abstract
The hydrogen bonding and amino-imino tautomerization of the systems of 2-amino-3-methoxypyridine (2A3MOP), 2-amino-6-methoxypyridine (2A6MOP), 2-amino-6-n-propoxypyridine (2A6NPOP), 2-amino-6-iso-propoxypyridine(2A6IPOP), 2-amino-4-methoxypyrimidine (2A4MOPM), 4-amino-2-methoxypyrimidine (4A2OPM), 4-amino-6-methoxypyrimidine (4A6MOPM), 2-amino-4-methoxy-6-methylpyrimidine (MMPM), and 2-amino-4,6-dimethoxypyrimidine (DMOPM), with acetic acid (AcOH) in n-hexane at room temperature were investigated by means of the UV absorption and fluorescence spectroscopy. From the UV absorption spectra the presence of the dual hydrogen-bonded complexes that linked by a 1:1 molar ratio with AcOH were found, since the enthalpy changes accompanying the hydrogen bond formation between 2A3MOP, 2A4MOPM, 4A2MOPM, 4A6MOPM, or MMPM, and AcOH were ca. 42.8-61.1kJmol(-1) in n-hexane. The fluorescence spectra of the 2A3MOP/AcOH, 2A4MOPM/AcOH, 4A6MOPM/AcOH, and MMPM/ AcOH systems revealed that the imino-tautomers were produced through double proton transfer in the amino hydrogen-bonded 1:1 complexes in the S1 state, but the imino-tautomer formation for the 4A2MOPM/AcOH system was not found on account of the steric hindrance due to the inversion of the methoxy group in the S1 state. The imino-tautomer for the MMPM/AcOH system fluoresces most intensely among these systems investigated. On the other hand, not only the formation of the corresponding amino dual hydrogen-bonded complex and but also that of imino-tautomer were prevented for the 2A6MOP/AcOH, 2A6NPOPM/AcOH, 2A6IPOP/AcOH, and DMOPM/AcOH systems, because of the steric hindrance of the methoxy group in both the S0 and S1 states. The theoretical approaches by an ab initio molecular orbital calculation were in accord with the experimental results.
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Affiliation(s)
- Teruyoshi Kitamura
- Department of Environmental Materials Science, Tokyo Denki University, Kanda, Tokyo, Japan
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37
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Iwata K, Kakita M, Hamaguchi HO. Picosecond Time-Resolved Fluorescence Study on Solute−Solvent Interaction of 2-Aminoquinoline in Room-Temperature Ionic Liquids: Aromaticity of Imidazolium-Based Ionic Liquids. J Phys Chem B 2007; 111:4914-9. [PMID: 17428083 DOI: 10.1021/jp067196v] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Time-resolved fluorescence spectra and fluorescence anisotropy decay of 2-aminoquinoline (2AQ) have been measured in eight room-temperature ionic liquids, including five imidazolium-based aromatic ionic liquids and three nonaromatic ionic liquids. The same experiments have also been carried out in several ordinary molecular liquids for comparison. The observed time-resolved fluorescence spectra indicate the formation of pi-pi aromatic complexes of 2AQ in some of the aromatic ionic liquids but not in the nonaromatic ionic liquids. The fluorescence anisotropy decay data show unusually slow rotational diffusion of 2AQ in the aromatic ionic liquids, suggesting the formation of solute-solvent complexes. The probe 2AQ molecule is likely to be incorporated in the possible local structure of ionic liquids, and hence the anisotropy decays only through the rotation of the whole local structure, making the apparent rotational diffusion of 2AQ slow. The rotational diffusion time decreases rapidly by adding a small amount of acetonitrile to the solution. This observation is interpreted in terms of the local structure formation in the aromatic ionic liquids and its destruction by acetonitrile. No unusual behavior upon addition of acetonitrile has been found for the nonaromatic ionic liquids. It is argued that the aromaticity of the imidazolium cation plays a key role in the local structure formation in imidazolium-based ionic liquids.
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Affiliation(s)
- Koichi Iwata
- Research Centre for Spectrochemistry, University of Tokyo Hongo 7-3-1, Tokyo 113-0033, Japan.
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38
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do N Varella MT, Arasaki Y, Ushiyama H, Takatsuka K, Wang K, McKoy V. Real-time observation of intramolecular proton transfer in the electronic ground state of chloromalonaldehyde: Anab initiostudy of time-resolved photoelectron spectra. J Chem Phys 2007; 126:054303. [PMID: 17302473 DOI: 10.1063/1.2432119] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
The authors report on studies of time-resolved photoelectron spectra of intramolecular proton transfer in the ground state of chloromalonaldehyde, employing ab initio photoionization matrix elements and effective potential surfaces of reduced dimensionality, wherein the couplings of proton motion to the other molecular vibrational modes are embedded by averaging over classical trajectories. In the simulations, population is transferred from the vibrational ground state to vibrationally hot wave packets by pumping to an excited electronic state and dumping with a time-delayed pulse. These pump-dump-probe simulations demonstrate that the time-resolved photoelectron spectra track proton transfer in the electronic ground state well and, furthermore, that the geometry dependence of the matrix elements enhances the tracking compared with signals obtained with the Condon approximation. Photoelectron kinetic energy distributions arising from wave packets localized in different basins are also distinguishable and could be understood, as expected, on the basis of the strength of the optical couplings in different regions of the ground state potential surface and the Franck-Condon overlaps of the ground state wave packets with the vibrational eigenstates of the ion potential surface.
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Affiliation(s)
- Márcio T do N Varella
- Department of Basic Science, Graduate School of Arts and Sciences, University of Tokyo, Komaba, Tokyo 153-8902, Japan
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Hazra MK, Chakraborty T. 2-Hydroxypyridine ↔ 2-Pyridone Tautomerization: Catalytic Influence of Formic Acid. J Phys Chem A 2006; 110:9130-6. [PMID: 16854025 DOI: 10.1021/jp060687v] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
A 1:1 hydrogen-bonded complex between 2-pyridone and formic acid has been characterized using laser-induced-fluorescence excitation and dispersed fluorescence spectroscopy in a supersonic jet expansion. Under the same expansion condition, the fluorescence signal of the tautomeric form of the complex (2-hydroxypyridine...formic acid) is absent, although both the bare tautomeric molecules exhibit well-resolved laser-induced-fluorescence spectra. Quantum chemistry calculation at the DFT/B3LYP/6-311++G** level predicts that in the ground electronic state the activation barrier for tautomerization from hydroxy to keto form in bare molecules is very large (approximately 34 kcal/mol). However, the process turns out to be nearly barrierless when assisted by formic acid, and double proton transfer occurs via a concerted mechanism.
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Affiliation(s)
- Montu K Hazra
- Department of Chemistry, Indian Institute of Technology, Kanpur, UP 208016, India
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Varella MTDN, Arasaki Y, Ushiyama H, McKoy V, Takatsuka K. Time-resolved photoelectron spectroscopy of proton transfer in the ground state of chloromalonaldehyde: Wave-packet dynamics on effective potential surfaces of reduced dimensionality. J Chem Phys 2006; 124:154302. [PMID: 16674221 DOI: 10.1063/1.2191852] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
We report on a simple but widely useful method for obtaining time-independent potential surfaces of reduced dimensionality wherein the coupling between reaction and substrate modes is embedded by averaging over an ensemble of classical trajectories. While these classically averaged potentials with their reduced dimensionality should be useful whenever a separation between reaction and substrate modes is meaningful, their use brings about significant simplification in studies of time-resolved photoelectron spectra in polyatomic systems where full-dimensional studies of skeletal and photoelectron dynamics can be prohibitive. Here we report on the use of these effective potentials in the studies of dump-probe photoelectron spectra of intramolecular proton transfer in chloromalonaldehyde. In these applications the effective potentials should provide a more realistic description of proton-substrate couplings than the sudden or adiabatic approximations commonly employed in studies of proton transfer. The resulting time-dependent photoelectron signals, obtained here assuming a constant value of the photoelectron matrix element for ionization of the wave packet, are seen to track the proton transfer.
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Affiliation(s)
- Márcio T do N Varella
- Instituto de Física Gleb Wataghin, Universidade Estadual de Campinas, Unicamp, 13083-970 Campinas, São Paulo, Brazil.
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Stanovnik B, Tišler M, Katritzky AR, Denisko OV. The Tautomerism of Heterocycles: Substituent Tautomerism of Six-Membered Ring Heterocycles. ADVANCES IN HETEROCYCLIC CHEMISTRY 2006. [DOI: 10.1016/s0065-2725(06)91001-0] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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Kitamura T, Hikita A, Ishikawa H, Fujimoto A. Photoinduced amino-imino tautomerization reaction in 2-aminopyrimidine and its methyl derivatives with acetic acid. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2005; 62:1157-64. [PMID: 15978861 DOI: 10.1016/j.saa.2005.04.008] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/30/2004] [Accepted: 04/07/2005] [Indexed: 05/03/2023]
Abstract
The electronic absorption and fluorescence spectra of 2-aminopyrimidine (2APM), 2-amino-4-methylpyrimidine (2A4MPM), and 2-amino-4,6-dimethylpyrimidine (2ADMPM) with acetic acid (AcOH) were measured in isooctane (2,2,4-trimethylpentane) at room temperature. From the absorption spectra, a hydrogen-bonded complex formation of the 2APM/AcOH, 2A4MPM/AcOH, and 2ADMPM/AcOH systems was recognized in isooctane. The enthalpy changes (-DeltaH) for the complex formation were estimated to be ca. 41.2-45.1 kJ mol-1 and increased in proportion to the numbers of the methyl group introduced into the 2APM. The -DeltaH values refer to the formation of the hydrogen-bonded 1:1 complex between the ring nitrogen atom and NH2 group of the aminopyrimidine and the OH and CO groups of AcOH, respectively. In the 2A4MPM/AcOH double hydrogen-bonded complex the OH group of AcOH is thought to be linked to the ring nitrogen at the 1-postion of 2A4MPM. The fluorescence spectral results indicate that the double proton transfer reaction takes place during the excited state, and gives rise to an imino-tautomer vibration emission, from analogy with the fluorescences of 1-methyl-2(1H)-pyrimidinimine (MPMI), 1,4-dimethyl-2(1H)-pyrimidinimine (DMPMI), and 1,4,6-trimethyl-2(1H)-pyrimidinimine (TMPMI). The fluorescence quantum yields of the imino-tautomers also increased in proportion to the numbers of the methyl group introduced into the 2APM.
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Affiliation(s)
- Teruyoshi Kitamura
- Department of Environmental Materials Science, Tokyo Denki University, Kanda, Chiyoda-ku, Tokyo 101-8457, Japan
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Arasaki Y, Yamazaki K, Varella MTDN, Takatsuka K. Real-time observation of ground state proton transfer: a model study. Chem Phys 2005. [DOI: 10.1016/j.chemphys.2004.10.043] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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45
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Excited state prototropism in 2-aminonicotinic acid: effect of solvents and acid–base concentrations. J Photochem Photobiol A Chem 2005. [DOI: 10.1016/j.jphotochem.2004.09.017] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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46
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Nayak MK, Dogra SK. Spectral characteristics of methyl 2-aminonicotinate: effect of solvents and acid–base concentrations. J Photochem Photobiol A Chem 2005. [DOI: 10.1016/j.jphotochem.2004.08.013] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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47
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Balamurali M, Dogra S. Photophysics of 2-(6′-hydroxy-3′-pyridyl)benzimidazole: effect of solvents and acid–base concentrations. J Mol Struct 2004. [DOI: 10.1016/j.molstruc.2004.03.053] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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Hayashi T, Mukamel S. Infrared Signatures of Proton Transfer in Guanine·Cytosine and Adenine·Thymine Base Pairs: DFT Study. Isr J Chem 2004. [DOI: 10.1560/m6na-f16j-nvkn-llm9] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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49
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Nayak MK, Dogra SK. Solvatochromism and prototropism in methyl 6-aminonicotinate: failure to observe amine-imine phototautomerism in solvents. J Mol Struct 2004. [DOI: 10.1016/j.molstruc.2004.06.014] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Affiliation(s)
- T E Dermota
- Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802, USA
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