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Local Control Theory in Trajectory Surface Hopping Dynamics Applied to the Excited‐State Proton Transfer of 4‐Hydroxyacridine 下载免费PDF全文
Dr. Basile F. E. Curchod Dr. Thomas J. Penfold Prof. Dr. Ursula Rothlisberger Dr. Ivano Tavernelli 《Chemphyschem》2015,16(10):2127-2133
The application of local control theory combined with nonadiabatic ab initio molecular dynamics to study the photoinduced intramolecular proton transfer reaction in 4‐hydroxyacridine was investigated. All calculations were performed within the framework of linear‐response time‐dependent density functional theory. The computed pulses revealed important information about the underlying excited‐state nuclear dynamics highlighting the involvement of collective vibrational modes that would normally be neglected in a study performed on model systems constrained to a subset of the full configuration space. This study emphasizes the strengths of local control theory for the design of pulses that can trigger chemical reactions associated with the population of a given molecular excited state. In addition, analysis of the generated pulses can help to shed new light on the photophysics and photochemistry of complex molecular systems. 相似文献
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Excited‐State Proton Transfer and Intramolecular Charge Transfer in 1,3‐Diketone Molecules 下载免费PDF全文
Dr. Marika Savarese Dr. Éric Brémond Prof. Dr. Carlo Adamo Prof. Dr. Nadia Rega Dr. Ilaria Ciofini 《Chemphyschem》2016,17(10):1530-1538
The photophysical signature of the tautomeric species of the asymmetric (N,N‐dimethylanilino)‐1,3‐diketone molecule are investigated using approaches rooted in density functional theory (DFT) and time‐dependent DFT (TD‐DFT). In particular, since this molecule, in the excited state, can undergo proton transfer reactions coupled to intramolecular charge transfer events, the different radiative and nonradiative channels are investigated by making use of different density‐based indexes. The use of these tools, together with the analysis of both singlet and triplet potential energy surfaces, provide new insights into excited‐state reactivity allowing one to rationalize the experimental findings including different behavior of the molecule as a function of solvent polarity. 相似文献
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Excited‐State Intramolecular Proton Transfer: Photoswitching in Salicylidene Methylamine Derivatives 下载免费PDF全文
Joanna Jankowska Dr. Michał F. Rode Prof. Joanna Sadlej Prof. Andrzej L. Sobolewski 《Chemphyschem》2014,15(8):1643-1652
The effect of chemical substitutions on the photophysical properties of the salicylidene methylamine molecule (SMA) (J. Jankowska, M. F. Rode, J. Sadlej, A. L. Sobolewski, ChemPhysChem, 2012 , 13, 4287–4294) is studied with the aid of ab initio electronic structure methods. It is shown that combining π‐electron‐donating and π‐electron‐withdrawing substituents results in an electron‐density push‐and‐pull effect on the energetic landscape of the ground and the lowest excited ππ* and nπ* singlet states of the system. The presented search for the most appropriate SMA derivatives with respect to their photoswitching functionality offers an efficient prescreening tool for finding chemical structures before real synthetic realization. 相似文献
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Dr. Daiana T. Mancini Dr. Kakali Sen Dr. Mario Barbatti Prof. Dr. Walter Thiel Prof. Dr. Teodorico C. Ramalho 《Chemphyschem》2015,16(16):3444-3449
We show by quantum mechanical/molecular mechanical (QM/MM) simulations that phenylbenzothiazoles undergoing an excited‐state proton transfer (ESPT) can be used to probe protein binding sites. For 2‐(2′‐hydroxy‐4′‐aminophenyl)benzothiazole (HABT) bound to a tyrosine kinase, the absolute and relative intensities of the fluorescence bands arising from the enol and keto forms are found to be strongly dependent on the active‐site conformation. The emission properties are tuned by hydrogen‐bonding interactions of HABT with the neighboring amino acid T766 and with active‐site water. The use of ESPT tuners opens the possibility of creating two‐color fluorescent markers for protein binding sites, with potential applications in the detection of mutations in cancer cell lines. 相似文献
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Wan‐Ting Hsieh Cheng‐Chih Hsieh Chin‐Hung Lai Dr. Yi‐Ming Cheng Dr. Mei‐Lin Ho Kung K. Wang Prof. Gene‐Hsiang Lee Pi‐Tai Chou Prof. 《Chemphyschem》2008,9(2):293-299
A four fused‐ring system 11‐propyl‐6H‐indolo[2,3‐b]quinoline ( 6 HIQ ) is strategically designed and synthesized; it possesses a central moiety of 7‐azaindole ( 7AI ) and undergoes excited‐state double proton transfer (ESDPT). Despite a barrierless type of ESDPT in the 6 HIQ dimer, femtosecond dynamics and a kinetic isotope effect provide indications for a stepwise ESDPT process in the 6 HIQ/7AI heterodimer, in which 6 HIQ (deuterated 6 HIQ ) delivers the pyrrolyl proton (deuteron) to 7AI (deuterated 7AI ) in less than 150 fs, forming an intermediate with a charge‐transfer‐like ion pair, followed by the transfer of a pyrrolyl proton (deuteron) from cation‐like 7AI (deuterated 7AI ) to the pyridinyl nitrogen of the anion‐like 6 HIQ (deuterated 6 HIQ ) in ~1.5±0.3 ps (3.5±0.3 ps). The barrier of second proton transfer is estimated to be 2.86 kcal mol?1 for the 6 HIQ/7AI heterodimer. 相似文献
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Inside Cover: Reaction Mechanism of Methanol to Formaldehyde over Fe‐ and FeO‐Modified Graphene (ChemPhysChem 5/2015) 下载免费PDF全文
Anawat Thivasasith Dr. Jakkapan Sirijaraensre Dr. Pipat Khongpracha Dr. Chompunuch Warakulwit Dr. Bavornpon Jansang Prof. Dr. Jumras Limtrakul 《Chemphyschem》2015,16(5):890-890
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《Chemphyschem》2003,4(11):1141-1141
The cover picture shows …?‥the solvent effect of water upon the lowest‐lying singlet excitation in acetone. The transition, which involves the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO), is blue‐shifted in water (sol) with respect to the gas phase (vac), since the HOMO is stronger stabilized in water than the LUMO. The authors calculate the absorption and fluorescence spectra of acetone in water with a hybrid Car–Parrinello quantum chemical/classical molecular dynamics approach and investigate the influence of the solvent. The lower part of the picture shows the excitation energy during a simulation. One configuration with a very high excitation energy (three hydrogen bonds, short C?O bond) and one configuration with a very low excitation energy (two hydrogen bonds, long C?O bond) are shown in detail. Find out more in the article by Rothlisberger and co‐workers on pages pp. 1177–1182. 相似文献
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Tracey M. McLean Deidre M. Cleland Samuel J. Lind Keith C. Gordon Prof. Shane G. Telfer Dr. Mark R. Waterland Dr. 《化学:亚洲杂志》2010,5(9):2036-2046
A recently reported new class of ruthenium complexes containing 2,2′‐bipyridine and a dipyrrin ligand in the coordination sphere exhibit both strong metal‐to‐ligand charge‐transfer (MLCT) and π–π* transitions. Quantitative analysis of the resonance Raman scattering intensities and absorption spectra reveals only weak electronic interactions between these states despite direct coordination of the bipyridyl and dipyrrin ligands to the central ruthenium atom. On the basis of DFT calculations and time‐dependent DFT (TD‐DFT), we propose that the electronic excited states closely resemble “pure” MLCT and π–π* states. Resonance Raman intensity analysis demonstrates that a large amplitude transannular torsional motion provides a mechanism for relaxation on the π–π* excited‐state surface. We assert that this result is generally applicable to a range of dipyrrin complexes such as boron–dipyrrin and metallodipyrrin systems. Despite the large torsional distortion between the phenyl ring and the dipyrromethene plane, π–π* excitation extends out onto the phenyl ring which may have important consequences in solar‐energy‐conversion applications of ruthenium–dipyrrin complexes. 相似文献
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Excited State Intramolecular Proton Transfer in Ethynyl‐Extended Regioisomers of 2‐(2′‐Hydroxyphenyl)benzothiazole: Effects of the Position and Electronic Nature of Substituent Groups 下载免费PDF全文
Dr. Qin Wang Dr. Longfei Xu Dr. Yahui Niu Dr. Yuxiu Wang Dr. Mao‐Sen Yuan Dr. Yanrong Zhang 《化学:亚洲杂志》2016,11(23):3454-3464
Although the organic dyes based on excited state intramolecular proton transfer (ESIPT) mechanism have attracted significant attention, the structure‐property relationship of ESIPT dyes needs to be further exploited. In this paper, three series of ethynyl‐extended regioisomers of 2‐(2′‐hydroxyphenyl)benzothiazole (HBT), at the 3′‐, 4′‐ and 6‐positions, respectively, have been synthesized. Changes in the absorption and emission spectra were correlated with the position and electronic nature of the substituent groups. Although 4′‐ and 6‐substituted HBT derivatives exhibited absorption bands at longer wavelengths, the keto‐emission of 3′‐substituted HBT derivatives was found at a substantially longer wavelength. The gradual red‐shifted fluorescence emission was found for 3′‐substituted HBT derivatives where the electron‐donating nature of substituent group increased, which was opposite to what was observed for 4′‐ and 6‐substituted HBT derivatives. The results derived from the theoretical calculations were in conformity with the experimental observations. Our study could potentially provide experimental and theoretical basis for designing novel ESIPT dyes that possess unique fluorescent properties. 相似文献
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Inside Cover: Bio‐Inspired Transition Metal–Organic Hydride Conjugates for Catalysis of Transfer Hydrogenation: Experiment and Theory (Chem. Eur. J. 7/2015) 下载免费PDF全文
Alex McSkimming Dr. Bun Chan Dr. Mohan M. Bhadbhade Dr. Graham E. Ball Prof. Stephen B. Colbran 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(7):2710-2710
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