151
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Riedle E, Bradler M, Wenninger M, Sailer CF, Pugliesi I. Electronic transient spectroscopy from the deep UV to the NIR: unambiguous disentanglement of complex processes. Faraday Discuss 2013; 163:139-58; discussion 243-75. [PMID: 24020200 DOI: 10.1039/c3fd00010a] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Affiliation(s)
- Eberhard Riedle
- Lehrstuhl für BioMolekulare Optik, Ludwig-Maximilians-Universität München, Oettingenstr. 67, 80538 Miünchen, Germany.
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152
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Szymczak JJ, Hofmann FD, Meuwly M. Structure and dynamics of solvent shells around photoexcited metal complexes. Phys Chem Chem Phys 2013; 15:6268-77. [DOI: 10.1039/c3cp44465a] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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153
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Jha SK, Ji M, Gaffney KJ, Boxer SG. Site-specific measurement of water dynamics in the substrate pocket of ketosteroid isomerase using time-resolved vibrational spectroscopy. J Phys Chem B 2012; 116:11414-21. [PMID: 22931297 DOI: 10.1021/jp305225r] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Little is known about the reorganization capacity of water molecules at the active sites of enzymes and how this couples to the catalytic reaction. Here, we study the dynamics of water molecules at the active site of a highly proficient enzyme, Δ(5)-3-ketosteroid isomerase (KSI), during a light-activated mimic of its catalytic cycle. Photoexcitation of a nitrile-containing photoacid, coumarin183 (C183), mimics the change in charge density that occurs at the active site of KSI during the first step of the catalytic reaction. The nitrile of C183 is exposed to water when bound to the KSI active site, and we used time-resolved vibrational spectroscopy as a site-specific probe to study the solvation dynamics of water molecules in the vicinity of the nitrile. We observed that water molecules at the active site of KSI are highly rigid, during the light-activated catalytic cycle, compared to the solvation dynamics observed in bulk water. On the basis of this result, we hypothesize that rigid water dipoles at the active site might help in the maintenance of the preorganized electrostatic environment required for efficient catalysis. The results also demonstrate the utility of nitrile probes in measuring the dynamics of local (H-bonded) water molecules in contrast to the commonly used fluorescence methods which measure the average behavior of primary and subsequent spheres of solvation.
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Affiliation(s)
- Santosh Kumar Jha
- Department of Chemistry, Stanford University, Stanford, California 94305-5012, USA
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154
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Liu W, Han F, Smith C, Fang C. Ultrafast conformational dynamics of pyranine during excited state proton transfer in aqueous solution revealed by femtosecond stimulated Raman spectroscopy. J Phys Chem B 2012; 116:10535-50. [PMID: 22671279 DOI: 10.1021/jp3020707] [Citation(s) in RCA: 72] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Proton transfer reaction plays an essential role in a myriad of chemical and biological processes, and to reveal the choreography of the proton motion intra- and intermolecularly, a spectroscopic technique capable of capturing molecular structural snapshots on the intrinsic time scale of proton transfer motions is needed. The photoacid pyranine (8-hydroxypyrene-1,3,6-trisulfonic acid, HPTS) serves as a paradigm case to dissect excited state proton transfer (ESPT) events in aqueous solution, triggered precisely by photoexcitation. We have used femtosecond stimulated Raman spectroscopy (FSRS) to yield novel insights into the ultrafast conformational dynamics of photoexcited HPTS in complex with water and acetate molecules. Marker bands attributed to the deprotonated form of HPTS (1139 cm(-1), ∼220 fs rise) appear earlier and faster than the monomer acetic acid peak (864 cm(-1), ∼530 fs rise), indicating that water molecules actively participate in the ESPT chain. Several key low-frequency modes at 106, 150, 195, and 321 cm(-1) have been identified to facilitate ESPT at different stages from 300 fs, 1 ps, to 6 ps and beyond, having distinctive dynamics contributing through hydrogen bonds with 0, 1, and more intervening water molecules. The time-resolved FSRS spectroscopy renders a direct approach to observe the reactive coupling between the vibrational degrees of freedom of photoexcited HPTS in action, therefore revealing the anharmonicity matrix both within HPTS and between HPTS and the neighboring acceptor molecules. The observed excited state conformational dynamics are along the ESPT multidimensional reaction coordinate and are responsible for the photoacidity of HPTS in aqueous solution.
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Affiliation(s)
- Weimin Liu
- Department of Chemistry, Oregon State University, Corvallis, Oregon 97331, United States
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155
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Donaldson PM, Strzalka H, Hamm P. High sensitivity transient infrared spectroscopy: a UV/Visible transient grating spectrometer with a heterodyne detected infrared probe. OPTICS EXPRESS 2012; 20:12761-12770. [PMID: 22714305 DOI: 10.1364/oe.20.012761] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
We describe here a high sensitivity means of performing time resolved UV/Visible pump, infrared probe spectroscopy using optically Heterodyne Detected UV-IR Transient Gratings. The experiment design employed is simple, robust and includes a novel means of generating phase locked pulse pairs that relies on only mirrors and a beamsplitter. A signal to noise ratio increase of 24 compared with a conventional pump-probe arrangement is demonstrated.
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Affiliation(s)
- Paul M Donaldson
- Institute of Physical Chemistry, University of Zürich, Winterthurerstrasse 190, Zürich CH-8057, Switzerland
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156
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Fingerhut BP, Sailer CF, Ammer J, Riedle E, de Vivie-Riedle R. Buildup and Decay of the Optical Absorption in the Ultrafast Photo-Generation and Reaction of Benzhydryl Cations in Solution. J Phys Chem A 2012; 116:11064-74. [DOI: 10.1021/jp300986t] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Benjamin P. Fingerhut
- Department Chemie, Ludwig-Maximilians-Universität (LMU), Butenandt-Strasse 11, 81377 München, Germany
| | - Christian F. Sailer
- Lehrstuhl für BioMolekulare
Optik, Ludwig-Maximilians-Universität (LMU), Oettingenstrasse 67, 80538 München, Germany
| | - Johannes Ammer
- Department Chemie, Ludwig-Maximilians-Universität (LMU), Butenandt-Strasse 11, 81377 München, Germany
| | - Eberhard Riedle
- Lehrstuhl für BioMolekulare
Optik, Ludwig-Maximilians-Universität (LMU), Oettingenstrasse 67, 80538 München, Germany
| | - Regina de Vivie-Riedle
- Department Chemie, Ludwig-Maximilians-Universität (LMU), Butenandt-Strasse 11, 81377 München, Germany
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157
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ZHANG XIAOYU, ZHANG WEIPING, MENG FANKAI. TIME-DEPENDENT DENSITY FUNCTIONAL THEORY STUDY ON DYNAMICS OF HYDROGEN BONDING IN EXCITED STATES OF TRANS-ACETANILIDE IN METHANOL SOLVENT. JOURNAL OF THEORETICAL & COMPUTATIONAL CHEMISTRY 2012. [DOI: 10.1142/s0219633612500290] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
The hydrogen-bonding dynamics in both singlet and triplet excited states of the trans-acetanilide ( AA ) in methanol ( MeOH ) solvent was investigated using the time-dependent density functional theory (TDDFT) method. Geometric optimizations of the hydrogen-bonded AA–MeOH complexes considered here as well as the isolated AA and MeOH molecules were performed using density functional theory (DFT) method. At the same time, the TDDFT method was performed to calculate the electronic transition energies and corresponding oscillation strengths of all the compounds in the low-lying electronically excited states. In this study, only the intermolecular hydrogen bonds C=O⋯H–O and N–H⋯O–H can be formed. A theoretical forecast that changes of hydrogen bonds in the low-lying electronic excited states was proposed. We discussed not only ground-state geometric structures and electronic excitation energies but also frontier molecular orbitals and electron density transition. The intermolecular hydrogen bonds between AA and MeOH molecules play an important role in the geometric structures and electronic excitation energies. Zhao et al. have put forward the relationship between the electronic spectra and hydrogen bonding dynamics for the first time. According to Zhao's rule, a redshift of the relevant electronic spectra will appear if hydrogen bond is strengthened, while the hydrogen bond weakening can make an electronic spectra shift to blue.
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Affiliation(s)
- XIAOYU ZHANG
- School of Materials Science and Engineering, Dailian University of Technology Dalian 116024, P. R. China
| | - WEIPING ZHANG
- School of Materials Science and Engineering, Dailian University of Technology Dalian 116024, P. R. China
| | - FANKAI MENG
- School of Materials Science and Engineering, Dailian University of Technology Dalian 116024, P. R. China
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158
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Li G, Magana D, Dyer RB. Photoinduced electron transfer in folic acid investigated by ultrafast infrared spectroscopy. J Phys Chem B 2012; 116:3467-75. [PMID: 22364409 PMCID: PMC3311227 DOI: 10.1021/jp300392a] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Conformational control of excited-state intramolecular electron transfer (ET) in folic acid (FA) has been investigated using femtosecond time-resolved infrared (TRIR) spectroscopy. Ultrafast excited-state ET between the pterin and the 4-aminobenzoyl subunits of FA is observed for the anionic form (at pH 10.0). An ET lifetime of 2.5 ps is estimated from Marcus theory for FA in the "U" conformation, in close agreement with the observed lifetime of 2.0 ps. Return to the ground state through the reverse ET reaction happens almost as rapidly, within 5 ps, resulting in rapid quenching of the singlet excited state. In mixed water:dimethyl sulfoxide solvent, ET becomes more unfavorable as FA adopts a more open conformation, thereby increasing the effective donor-acceptor distance and reducing the coupling energy. In contrast, no ET is observed for the cationic form of FA at low pH (6.0). In this case, the initial singlet excited state is localized on the pterin moiety of FA, and the excited-state charge distribution evolves with time. The charge redistribution in the pterin that occurs with intersystem crossing to the triplet state is characterized by changes in the transient IR spectrum. The excited-state lifetime is much longer in the absence of an ET quenching pathway. These results provide new insight into the mechanism of photodegradation and toxicity of FA. Ultrafast intramolecular ET in closed conformations of FA rapidly quenches the excited state and prevents efficient triplet state formation. Thus, conformations of FA that allow ultrafast intra-ET and rapid quenching of the singlet excited state play a key role in inhibiting pathological pathways following photoexcitation of FA.
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Affiliation(s)
- Guifeng Li
- Department of Chemistry, Emory University, Atlanta, Georgia, 30322, United States
| | - Donny Magana
- Department of Chemistry, Emory University, Atlanta, Georgia, 30322, United States
| | - R. Brian Dyer
- Department of Chemistry, Emory University, Atlanta, Georgia, 30322, United States
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159
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Ghosh HN, Adamczyk K, Verma S, Dreyer J, Nibbering ETJ. On the role of hydrogen bonds in photoinduced electron-transfer dynamics between 9-fluorenone and amine solvents. Chemistry 2012; 18:4930-7. [PMID: 22389093 DOI: 10.1002/chem.201102994] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2011] [Revised: 12/23/2011] [Indexed: 11/09/2022]
Abstract
Using ultrafast fluorescence upconversion and mid-infrared spectroscopy, we explore the role of hydrogen bonds in the photoinduced electron transfer (ET) between 9-fluorenone (FLU) and the solvents trimethylamine (TEA) and dimethylamine (DEA). FLU shows hydrogen-bond dynamics in the methanol solvent upon photoexcitation, and similar effects may be anticipated when using DEA, whereas no hydrogen bonds can occur in TEA. Photoexcitation of the electron-acceptor dye molecule FLU with a 400 nm pump pulse induces ultrafast ET from the amine solvents, which is followed by 100 fs IR probe pulses as well as fluorescence upconversion, monitoring the time evolution of marker bands of the FLU S(1) state and the FLU radical anion, and an overtone band of the amine solvent, marking the transient generation of the amine radical cation. A comparison of the experimentally determined forward charge-separation and backward charge-recombination rates for the FLU-TEA and FLU-DEA reaction systems with the driving-force dependencies calculated for the forward and backward ET rates reveals that additional degrees of freedom determine the ET reaction dynamics for the FLU-DEA system. We suggest that hydrogen bonding between the DEA molecules plays a key role in this behaviour.
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Affiliation(s)
- Hirendra N Ghosh
- Radiation & Photochemistry Division, Bhabha Atomic Research Centre, Mumbai 400 085, India.
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160
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Theoretical study on the excited-state photoinduced electron transfer facilitated by hydrogen bonding strengthening in the C337–AN/MAN complexes. COMPUT THEOR CHEM 2012. [DOI: 10.1016/j.comptc.2012.01.026] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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161
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Cannizzo A. Ultrafast UV spectroscopy: from a local to a global view of dynamical processes in macromolecules. Phys Chem Chem Phys 2012; 14:11205-23. [DOI: 10.1039/c2cp40567a] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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162
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Karton-Lifshin N, Presiado I, Erez Y, Gepshtein R, Shabat D, Huppert D. Ultrafast Excited-State Intermolecular Proton Transfer of Cyanine Fluorochrome Dyes. J Phys Chem A 2011; 116:85-92. [DOI: 10.1021/jp2095856] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Naama Karton-Lifshin
- Raymond and Beverly Sackler Faculty of Exact Sciences, School of Chemistry, Tel Aviv University, Tel Aviv 69978, Israel
| | - Itay Presiado
- Raymond and Beverly Sackler Faculty of Exact Sciences, School of Chemistry, Tel Aviv University, Tel Aviv 69978, Israel
| | - Yuval Erez
- Raymond and Beverly Sackler Faculty of Exact Sciences, School of Chemistry, Tel Aviv University, Tel Aviv 69978, Israel
| | - Rinat Gepshtein
- Raymond and Beverly Sackler Faculty of Exact Sciences, School of Chemistry, Tel Aviv University, Tel Aviv 69978, Israel
| | - Doron Shabat
- Raymond and Beverly Sackler Faculty of Exact Sciences, School of Chemistry, Tel Aviv University, Tel Aviv 69978, Israel
| | - Dan Huppert
- Raymond and Beverly Sackler Faculty of Exact Sciences, School of Chemistry, Tel Aviv University, Tel Aviv 69978, Israel
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163
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Sahoo SK, Umapathy S, Parker AW. Time-resolved resonance Raman spectroscopy: exploring reactive intermediates. APPLIED SPECTROSCOPY 2011; 65:1087-115. [PMID: 21986070 DOI: 10.1366/11-06406] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
The study of reaction mechanisms involves systematic investigations of the correlation between structure, reactivity, and time. The challenge is to be able to observe the chemical changes undergone by reactants as they change into products via one or several intermediates such as electronic excited states (singlet and triplet), radicals, radical ions, carbocations, carbanions, carbenes, nitrenes, nitrinium ions, etc. The vast array of intermediates and timescales means there is no single "do-it-all" technique. The simultaneous advances in contemporary time-resolved Raman spectroscopic techniques and computational methods have done much towards visualizing molecular fingerprint snapshots of the reactive intermediates in the microsecond to femtosecond time domain. Raman spectroscopy and its sensitive counterpart resonance Raman spectroscopy have been well proven as means for determining molecular structure, chemical bonding, reactivity, and dynamics of short-lived intermediates in solution phase and are advantageous in comparison to commonly used time-resolved absorption and emission spectroscopy. Today time-resolved Raman spectroscopy is a mature technique; its development owes much to the advent of pulsed tunable lasers, highly efficient spectrometers, and high speed, highly sensitive multichannel detectors able to collect a complete spectrum. This review article will provide a brief chronological development of the experimental setup and demonstrate how experimentalists have conquered numerous challenges to obtain background-free (removing fluorescence), intense, and highly spectrally resolved Raman spectra in the nanosecond to microsecond (ns-μs) and picosecond (ps) time domains and, perhaps surprisingly, laid the foundations for new techniques such as spatially offset Raman spectroscopy.
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Affiliation(s)
- Sangram Keshari Sahoo
- Department of Inorganic and Physical Chemistry, Indian Institute of Science, Bangalore-560012, India
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164
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Prémont-Schwarz M, Xiao D, Batista VS, Nibbering ETJ. The O-H stretching mode of a prototypical photoacid as a local dielectric probe. J Phys Chem A 2011; 115:10511-6. [PMID: 21851092 DOI: 10.1021/jp207642k] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
We investigate the OH stretch vibrational frequency shifts of a prototype photoacid, 2-naphthol (2N), when dissolved in solvents of low polarity. We combine femtosecond mid-infrared spectroscopy and a theoretical model based on the Pullin-van der Zwan-Hynes perturbative approach to explore vibrational solvatochromic effects in the ground S(0) and the first electronically excited (1)L(b) states. The model is parametrized using density functional theory (DFT), at the B3LYP/TZVP and TD-B3LYP/TZVP levels for the 2N chromophore in the S(0) and (1)L(b) states, respectively. From the agreement between experiment and theory we conclude that vibrational solvatochromic effects are dominated by the instantaneous dielectric response of the solvent, while time-dependent nuclear rearrangements are of secondary importance.
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Affiliation(s)
- Mirabelle Prémont-Schwarz
- Max Born Institut für Nichtlineare Optik und Kurzzeitspektroskopie, Max Born Strasse 2A, D-12489 Berlin, Germany
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165
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Mohammed OF, Luber S, Batista VS, Nibbering ETJ. Ultrafast Branching of Reaction Pathways in 2-(2′-Hydroxyphenyl)benzothiazole in Polar Acetonitrile Solution. J Phys Chem A 2011; 115:7550-8. [DOI: 10.1021/jp202277t] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Affiliation(s)
- Omar F. Mohammed
- Max Born Institut für Nichtlineare Optik und Kurzzeitspektroskopie, Max Born Strasse 2A, D-12489 Berlin, Germany
| | - Sandra Luber
- Department of Chemistry, Yale University, P.O. Box 208107, New Haven, Connecticut 06520-8107, United States
| | - Victor S. Batista
- Department of Chemistry, Yale University, P.O. Box 208107, New Haven, Connecticut 06520-8107, United States
| | - Erik T. J. Nibbering
- Max Born Institut für Nichtlineare Optik und Kurzzeitspektroskopie, Max Born Strasse 2A, D-12489 Berlin, Germany
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166
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Weidinger D, Brown DJ, Owrutsky JC. Transient absorption studies of vibrational relaxation and photophysics of Prussian blue and ruthenium purple nanoparticles. J Chem Phys 2011; 134:124510. [DOI: 10.1063/1.3564918] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
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167
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Krystkowiak E, Maciejewski A. Changes in energy of three types of hydrogen bonds upon excitation of aminocoumarins determined from absorption solvatochromic experiments. Phys Chem Chem Phys 2011; 13:11317-24. [DOI: 10.1039/c1cp20767a] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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168
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Greetham GM, Burgos P, Cao Q, Clark IP, Codd PS, Farrow RC, George MW, Kogimtzis M, Matousek P, Parker AW, Pollard MR, Robinson DA, Xin ZJ, Towrie M. ULTRA: A Unique Instrument for Time-Resolved Spectroscopy. APPLIED SPECTROSCOPY 2010; 64:1311-1319. [PMID: 21144146 DOI: 10.1366/000370210793561673] [Citation(s) in RCA: 154] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
We report the development of a high-sensitivity time-resolved infrared and Raman spectrometer with exceptional experimental flexibility based on a 10-kHz synchronized dual-arm femtosecond and picosecond laser system. Ultrafast high-average-power titanium sapphire lasers and optical parametric amplifiers provide wavelength tuning from the ultraviolet (UV) to the mid-infrared region. Customized silicon, indium gallium arsenide, and mercury cadmium telluride linear array detectors are provided to monitor the probe laser intensity in the UV to mid-infrared wavelength range capable of measuring changes in sample absorbance of ΔOD ~ 10(-5) in 1 second. The system performance is demonstrated for the time-resolved infrared, two-dimensional (2D) infrared, and femtosecond stimulated Raman spectroscopy techniques with organometallic intermediates, organic excited states, and the dynamics of the tertiary structure of DNA.
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Affiliation(s)
- Gregory M Greetham
- Central Laser Facility, Research Complex at Harwell, Science and Technology Facilities Council, Rutherford Appleton Laboratory, Harwell Science and Innovation Campus, Didcot, Oxfordshire, OX11 0QX, UK.
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169
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Sytina OA, Alexandre MT, Heyes DJ, Hunter CN, Robert B, van Grondelle R, Groot ML. Enzyme activation and catalysis: characterisation of the vibrational modes of substrate and product in protochlorophyllide oxidoreductase. Phys Chem Chem Phys 2010; 13:2307-13. [PMID: 21103538 DOI: 10.1039/c0cp01686a] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
The light-dependent reduction of protochlorophyllide, a key step in the synthesis of chlorophyll, is catalyzed by the enzyme protochlorophyllide oxidoreductase (POR) and requires two photons (O. A. Sytina et al., Nature, 2008, 456, 1001-1008). The first photon activates the enzyme-substrate complex, a subsequent second photon initiates the photochemistry by triggering the formation of a catalytic intermediate. These two events are characterized by different spectral changes in the infra-red spectral region. Here, we investigate the vibrational frequencies of the POR-bound and unbound substrate, and product, and thus provide a detailed assignment of the spectral changes in the 1800-1250 cm(-1) region associated with the catalytic conversion of PChlide:NADPH:TyrOH into Chlide:NADP(+):TyrO(-). Fluorescence line narrowed spectra of the POR-bound Pchlide reveal a C=O keto group downshifted by more than 20 cm(-1) to a relatively low vibrational frequency of 1653 cm(-1), as compared to the unbound Pchlide, indicating that binding of the chromophore to the protein occurs via strong hydrogen bond(s). The frequencies of the C=C vibrational modes are consistent with a six-coordinated state of the POR-bound Pchlide, suggesting that there are two coordination interactions between the central Mg atom of the chromophore and protein residues, and/or a water molecule. The frequencies of the C=C vibrational modes of Chlide are consistent with a five-coordinated state, indicating a single interaction between the central Mg atom of the chromophore and a water molecule. Rapid-scan FTIR measurements on the Pchlide:POR:NADPH complex at 4 cm(-1) spectral resolution reveal a new band in the 1670 cm(-1) region. The FTIR spectra of the enzyme activation phase indicate involvement of a nucleotide-binding structural motif, and an increased exposure of the protein to solvent after activation.
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Affiliation(s)
- Olga A Sytina
- Department of Physics and Astronomy, Faculty of Sciences, Vrije Universiteit, De Boelelaan 1081, 1081 HV Amsterdam, The Netherlands.
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170
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Lockard JV, Rachford AA, Smolentsev G, Stickrath AB, Wang X, Zhang X, Atenkoffer K, Jennings G, Soldatov A, Rheingold AL, Castellano FN, Chen LX. Triplet Excited State Distortions in a Pyrazolate Bridged Platinum Dimer Measured by X-ray Transient Absorption Spectroscopy. J Phys Chem A 2010; 114:12780-7. [DOI: 10.1021/jp1088299] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Jenny V. Lockard
- Chemical Sciences and Engineering Division and X-ray Sciences Division, Argonne National Laboratory, Argonne, Illinois 60439, United States, Department of Chemistry, Northwestern University, Evanston, Illinois 60208, United States, Department of Chemistry & Center for Photochemical Sciences, Bowling Green State University, Bowling Green, Ohio 43403, United States, Research Center for Nanoscale Structure of Matter, Southern Federal University, Sorge 5, Rostov-na-Donu, 344090 Russia, Department of Chemical
| | - Aaron A. Rachford
- Chemical Sciences and Engineering Division and X-ray Sciences Division, Argonne National Laboratory, Argonne, Illinois 60439, United States, Department of Chemistry, Northwestern University, Evanston, Illinois 60208, United States, Department of Chemistry & Center for Photochemical Sciences, Bowling Green State University, Bowling Green, Ohio 43403, United States, Research Center for Nanoscale Structure of Matter, Southern Federal University, Sorge 5, Rostov-na-Donu, 344090 Russia, Department of Chemical
| | - Grigory Smolentsev
- Chemical Sciences and Engineering Division and X-ray Sciences Division, Argonne National Laboratory, Argonne, Illinois 60439, United States, Department of Chemistry, Northwestern University, Evanston, Illinois 60208, United States, Department of Chemistry & Center for Photochemical Sciences, Bowling Green State University, Bowling Green, Ohio 43403, United States, Research Center for Nanoscale Structure of Matter, Southern Federal University, Sorge 5, Rostov-na-Donu, 344090 Russia, Department of Chemical
| | - Andrew B. Stickrath
- Chemical Sciences and Engineering Division and X-ray Sciences Division, Argonne National Laboratory, Argonne, Illinois 60439, United States, Department of Chemistry, Northwestern University, Evanston, Illinois 60208, United States, Department of Chemistry & Center for Photochemical Sciences, Bowling Green State University, Bowling Green, Ohio 43403, United States, Research Center for Nanoscale Structure of Matter, Southern Federal University, Sorge 5, Rostov-na-Donu, 344090 Russia, Department of Chemical
| | - Xianghuai Wang
- Chemical Sciences and Engineering Division and X-ray Sciences Division, Argonne National Laboratory, Argonne, Illinois 60439, United States, Department of Chemistry, Northwestern University, Evanston, Illinois 60208, United States, Department of Chemistry & Center for Photochemical Sciences, Bowling Green State University, Bowling Green, Ohio 43403, United States, Research Center for Nanoscale Structure of Matter, Southern Federal University, Sorge 5, Rostov-na-Donu, 344090 Russia, Department of Chemical
| | - Xiaoyi Zhang
- Chemical Sciences and Engineering Division and X-ray Sciences Division, Argonne National Laboratory, Argonne, Illinois 60439, United States, Department of Chemistry, Northwestern University, Evanston, Illinois 60208, United States, Department of Chemistry & Center for Photochemical Sciences, Bowling Green State University, Bowling Green, Ohio 43403, United States, Research Center for Nanoscale Structure of Matter, Southern Federal University, Sorge 5, Rostov-na-Donu, 344090 Russia, Department of Chemical
| | - Klaus Atenkoffer
- Chemical Sciences and Engineering Division and X-ray Sciences Division, Argonne National Laboratory, Argonne, Illinois 60439, United States, Department of Chemistry, Northwestern University, Evanston, Illinois 60208, United States, Department of Chemistry & Center for Photochemical Sciences, Bowling Green State University, Bowling Green, Ohio 43403, United States, Research Center for Nanoscale Structure of Matter, Southern Federal University, Sorge 5, Rostov-na-Donu, 344090 Russia, Department of Chemical
| | - Guy Jennings
- Chemical Sciences and Engineering Division and X-ray Sciences Division, Argonne National Laboratory, Argonne, Illinois 60439, United States, Department of Chemistry, Northwestern University, Evanston, Illinois 60208, United States, Department of Chemistry & Center for Photochemical Sciences, Bowling Green State University, Bowling Green, Ohio 43403, United States, Research Center for Nanoscale Structure of Matter, Southern Federal University, Sorge 5, Rostov-na-Donu, 344090 Russia, Department of Chemical
| | - Alexander Soldatov
- Chemical Sciences and Engineering Division and X-ray Sciences Division, Argonne National Laboratory, Argonne, Illinois 60439, United States, Department of Chemistry, Northwestern University, Evanston, Illinois 60208, United States, Department of Chemistry & Center for Photochemical Sciences, Bowling Green State University, Bowling Green, Ohio 43403, United States, Research Center for Nanoscale Structure of Matter, Southern Federal University, Sorge 5, Rostov-na-Donu, 344090 Russia, Department of Chemical
| | - Arnold L. Rheingold
- Chemical Sciences and Engineering Division and X-ray Sciences Division, Argonne National Laboratory, Argonne, Illinois 60439, United States, Department of Chemistry, Northwestern University, Evanston, Illinois 60208, United States, Department of Chemistry & Center for Photochemical Sciences, Bowling Green State University, Bowling Green, Ohio 43403, United States, Research Center for Nanoscale Structure of Matter, Southern Federal University, Sorge 5, Rostov-na-Donu, 344090 Russia, Department of Chemical
| | - Felix N. Castellano
- Chemical Sciences and Engineering Division and X-ray Sciences Division, Argonne National Laboratory, Argonne, Illinois 60439, United States, Department of Chemistry, Northwestern University, Evanston, Illinois 60208, United States, Department of Chemistry & Center for Photochemical Sciences, Bowling Green State University, Bowling Green, Ohio 43403, United States, Research Center for Nanoscale Structure of Matter, Southern Federal University, Sorge 5, Rostov-na-Donu, 344090 Russia, Department of Chemical
| | - Lin X. Chen
- Chemical Sciences and Engineering Division and X-ray Sciences Division, Argonne National Laboratory, Argonne, Illinois 60439, United States, Department of Chemistry, Northwestern University, Evanston, Illinois 60208, United States, Department of Chemistry & Center for Photochemical Sciences, Bowling Green State University, Bowling Green, Ohio 43403, United States, Research Center for Nanoscale Structure of Matter, Southern Federal University, Sorge 5, Rostov-na-Donu, 344090 Russia, Department of Chemical
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Yang M, Szyc Ł, Dreyer J, Nibbering ETJ, Elsaesser T. The Hydrogen-Bonded 2-Pyridone Dimer Model System. 2. Femtosecond Mid-Infrared Pump−Probe Study. J Phys Chem A 2010; 114:12195-201. [PMID: 21038900 DOI: 10.1021/jp108096y] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Affiliation(s)
- Ming Yang
- Max Born Institut für Nichtlineare Optik und Kurzzeitspektroskopie, Max Born Strasse 2A, D-12489 Berlin, Germany
| | - Łukasz Szyc
- Max Born Institut für Nichtlineare Optik und Kurzzeitspektroskopie, Max Born Strasse 2A, D-12489 Berlin, Germany
| | - Jens Dreyer
- Max Born Institut für Nichtlineare Optik und Kurzzeitspektroskopie, Max Born Strasse 2A, D-12489 Berlin, Germany
| | - Erik T. J. Nibbering
- Max Born Institut für Nichtlineare Optik und Kurzzeitspektroskopie, Max Born Strasse 2A, D-12489 Berlin, Germany
| | - Thomas Elsaesser
- Max Born Institut für Nichtlineare Optik und Kurzzeitspektroskopie, Max Born Strasse 2A, D-12489 Berlin, Germany
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172
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Ye S, Markelz A. Hydration Effects on Energy Relaxation of Ferric Cytochrome C Films after Soret-Band Photoexcitation. J Phys Chem B 2010; 114:15151-7. [DOI: 10.1021/jp104217j] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Affiliation(s)
- Shuji Ye
- Hefei National Laboratory for Physical Sciences at Microscale, University of Science and Technology of China, Hefei, Anhui, People’s Republic of China 230026, and Department of Physics, University at Buffalo, SUNY, 239 Fronczak Hall, Buffalo, New York 14260-1500, United States
| | - Andrea Markelz
- Hefei National Laboratory for Physical Sciences at Microscale, University of Science and Technology of China, Hefei, Anhui, People’s Republic of China 230026, and Department of Physics, University at Buffalo, SUNY, 239 Fronczak Hall, Buffalo, New York 14260-1500, United States
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173
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Ghosh R, Mondal JA, Palit DK. Ultrafast Dynamics of the Excited States of Curcumin in Solution. J Phys Chem B 2010; 114:12129-43. [DOI: 10.1021/jp1038249] [Citation(s) in RCA: 75] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Affiliation(s)
- Rajib Ghosh
- Radiation & Photochemistry Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400085, India
| | - Jahur A. Mondal
- Radiation & Photochemistry Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400085, India
| | - Dipak K. Palit
- Radiation & Photochemistry Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400085, India
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174
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Sytina OA, van Stokkum IHM, Heyes DJ, Hunter CN, van Grondelle R, Groot ML. Protochlorophyllide excited-state dynamics in organic solvents studied by time-resolved visible and mid-infrared spectroscopy. J Phys Chem B 2010; 114:4335-44. [PMID: 20205376 DOI: 10.1021/jp9089326] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Protochlorophyllide (PChlide) is a precursor in the biosynthesis of chlorophyll. Complexed with NADPH to the enzyme protochlorophyllide oxidoreductase (POR), it is reduced to chlorophyllide, a process that occurs via a set of spectroscopically distinct intermediate states and is initiated from the excited state of PChlide. To obtain a better understanding of these catalytic events, we characterized the excited state dynamics of PChlide in the solvents tetrahydrofuran (THF), methanol, and Tris/Triton buffer using ultrafast transient absorption in the visible and mid-infrared spectral regions and time-resolved fluorescence emission experiments. For comparison, we present time-resolved transient absorption measurements of chlorophyll a in THF. From the combined analysis of these experiments, we derive that during the 2-3 ns excited state lifetime an extensive multiphasic quenching of the emission occurs due to solvation of the excited state, which is in agreement with the previously proposed internal charge transfer (ICT) character of the S1 state ( Zhao , G. J. ; Han , K. L. Biophys. J. 2008 , 94 , 38 ). The solvation process in methanol occurs in conjunction with a strengthening of a hydrogen bond to the Pchlide keto carbonyl group. We demonstrate that the internal conversion from the S2 to S1 excited states is remarkably slow and stretches out on to the 700 fs time scale, causing a rise of blue-shifted signals in the transient absorption and a gain of emission in the time-resolved fluorescence. A triplet state is populated on the nanosecond time scale with a maximal yield of approximately 23%. The consequences of these observations for the catalytic pathway and the role of the triplet and ICT state in activation of the enzyme are discussed.
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Affiliation(s)
- Olga A Sytina
- Department of Physics and Astronomy, Faculty of Sciences, Vrije Universiteit, De Boelelaan 1081, 1081 HV Amsterdam, The Netherlands.
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175
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Ihee H, Wulff M, Kim J, Adachi SI. Ultrafast X-ray scattering: structural dynamics from diatomic to protein molecules. INT REV PHYS CHEM 2010. [DOI: 10.1080/0144235x.2010.498938] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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176
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177
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178
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Kim J, Kim KH, Lee JH, Ihee H. Ultrafast X-ray diffraction in liquid, solution and gas: present status and future prospects. Acta Crystallogr A 2010; 66:270-80. [PMID: 20164650 DOI: 10.1107/s0108767309052052] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2009] [Accepted: 12/03/2009] [Indexed: 11/10/2022] Open
Abstract
In recent years, the time-resolved X-ray diffraction technique has been established as an excellent tool for studying reaction dynamics and protein structural transitions with the aid of 100 ps X-ray pulses generated from third-generation synchrotrons. The forthcoming advent of the X-ray free-electron laser (XFEL) will bring a substantial improvement in pulse duration, photon flux and coherence of X-ray pulses, making time-resolved X-ray diffraction even more powerful. This technical breakthrough is envisioned to revolutionize the field of reaction dynamics associated with time-resolved diffraction methods. Examples of candidates for the first femtosecond X-ray diffraction experiments using highly coherent sub-100 fs pulses generated from XFELs are presented in this paper. They include the chemical reactions of small molecules in the gas and solution phases, solvation dynamics and protein structural transitions. In these potential experiments, ultrafast reaction dynamics and motions of coherent rovibrational wave packets will be monitored in real time. In addition, high photon flux and coherence of XFEL-generated X-ray pulses give the prospect of single-molecule diffraction experiments.
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Affiliation(s)
- Jeongho Kim
- Center for Time-Resolved Diffraction, Department of Chemistry, and Graduate School of Nanoscience and Technology (WCU), KAIST, Daejeon 305-701, Republic of Korea
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179
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Mondal JA, Samant V, Varne M, Singh AK, Ghanty TK, Ghosh HN, Palit DK. The Role of Hydrogen-Bonding Interactions in the Ultrafast Relaxation Dynamics of the Excited States of 3- and 4-Aminofluoren-9-ones. Chemphyschem 2009; 10:2995-3012. [DOI: 10.1002/cphc.200900325] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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180
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Brust T, Malkmus S, Draxler S, Ahmed SA, Rück-Braun K, Zinth W, Braun M. Photochemistry with thermal versus optical excess energy: Ultrafast cycloreversion of indolylfulgides and indolylfulgimides. J Photochem Photobiol A Chem 2009. [DOI: 10.1016/j.jphotochem.2009.07.012] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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181
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Kim TK, Lee JH, Wulff M, Kong Q, Ihee H. Spatiotemporal Kinetics in Solution Studied by Time-Resolved X-Ray Liquidography (Solution Scattering). Chemphyschem 2009; 10:1958-80. [DOI: 10.1002/cphc.200900154] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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182
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Li G, Parimal K, Vyas S, Hadad CM, Flood AH, Glusac KD. Pinpointing the Extent of Electronic Delocalization in the Re(I)-to-Tetrazine Charge-Separated Excited State Using Time-Resolved Infrared Spectroscopy. J Am Chem Soc 2009; 131:11656-7. [DOI: 10.1021/ja903901n] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Guifeng Li
- Department of Chemistry, Bowling Green State University, Bowling Green, Ohio 43403, Department of Chemistry, Indiana University, 800 East Kirkwood Avenue, Bloomington, Indiana 47405, and Department of Chemistry, The Ohio State University, 100 West 18th Avenue, Columbus, Ohio 43210
| | - Kumar Parimal
- Department of Chemistry, Bowling Green State University, Bowling Green, Ohio 43403, Department of Chemistry, Indiana University, 800 East Kirkwood Avenue, Bloomington, Indiana 47405, and Department of Chemistry, The Ohio State University, 100 West 18th Avenue, Columbus, Ohio 43210
| | - Shubham Vyas
- Department of Chemistry, Bowling Green State University, Bowling Green, Ohio 43403, Department of Chemistry, Indiana University, 800 East Kirkwood Avenue, Bloomington, Indiana 47405, and Department of Chemistry, The Ohio State University, 100 West 18th Avenue, Columbus, Ohio 43210
| | - Christopher M. Hadad
- Department of Chemistry, Bowling Green State University, Bowling Green, Ohio 43403, Department of Chemistry, Indiana University, 800 East Kirkwood Avenue, Bloomington, Indiana 47405, and Department of Chemistry, The Ohio State University, 100 West 18th Avenue, Columbus, Ohio 43210
| | - Amar H. Flood
- Department of Chemistry, Bowling Green State University, Bowling Green, Ohio 43403, Department of Chemistry, Indiana University, 800 East Kirkwood Avenue, Bloomington, Indiana 47405, and Department of Chemistry, The Ohio State University, 100 West 18th Avenue, Columbus, Ohio 43210
| | - Ksenija D. Glusac
- Department of Chemistry, Bowling Green State University, Bowling Green, Ohio 43403, Department of Chemistry, Indiana University, 800 East Kirkwood Avenue, Bloomington, Indiana 47405, and Department of Chemistry, The Ohio State University, 100 West 18th Avenue, Columbus, Ohio 43210
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183
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Mohammed O, Kwon OH, Othon C, Zewail A. Charge Transfer Assisted by Collective Hydrogen-Bonding Dynamics. Angew Chem Int Ed Engl 2009; 48:6251-6. [DOI: 10.1002/anie.200902340] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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184
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Mohammed O, Kwon OH, Othon C, Zewail A. Charge Transfer Assisted by Collective Hydrogen-Bonding Dynamics. Angew Chem Int Ed Engl 2009. [DOI: 10.1002/ange.200902340] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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185
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Kim J, Wu Y, Brédas JL, Batista VS. Quantum Dynamics of the Excited-State Intramolecular Proton Transfer in 2-(2′-Hydroxyphenyl)benzothiazole. Isr J Chem 2009. [DOI: 10.1560/ijc.49.2.187] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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186
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Mohammed OF, Ahmed SA, Vauthey E, Nibbering ETJ. Photoinduced ring-opening of a photochromic dihydroindolizine derivative monitored with femtosecond visible and infrared spectroscopy. J Phys Chem A 2009; 113:5061-5. [PMID: 19331335 DOI: 10.1021/jp811248u] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
We present results of a femtosecond spectroscopy study of the ring-opening dynamics of the photochromic compound trimethyl-1'H-spiro[fluorene-9,1'-pyrrolo[1,2-b]pyridazines]-2',3',6'-tricarboxylate (also known as dihydroindolizine and abbreviated as DHI) in solvents of different polarities. We follow the ring-opening dynamics of photoexcited DHI by probing the transient response in the visible region between 450 and 700 nm, as well as in the fingerprint region between 1100 and 1800 cm(-1). We conclude that photoexcited DHI converts into the ring-opened betaine isomer while remaining in the electronic excited state. Subsequent electronic excited-state decay on a time scale of 40-80 ps results in regeneration of ground-state DHI (0.75-0.9 quantum yield) or betaine photoproduct, the exact value for DHI quantum yield recoveries and rates being solvent dependent.
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Affiliation(s)
- Omar F Mohammed
- Max Born Institut fur Nichtlineare Optik and Kurzzeitspektroskopie, Max Born Strasse 2A, D-12489 Berlin, Germany
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187
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Abstract
Recent advances in ultrafast laser technology have spurred investigations of microheterogeneous solutions. In particular, researchers have explored details of reverse micelles (RMs), which present isolated droplets of polar solvent sequestered from a continuous nonpolar phase by a surfactant layer. This review explores recent studies utilizing a variety of ultrafast laser techniques to uncover details about structure and dynamics in various RMs. Using ultrafast vibrational spectroscopy, researchers have probed hydrogen-bond dynamics and vibrational energy relaxation in RMs. These studies have developed our understanding of reverse micellar structure, identifying varying water environments in the RMs. In a plethora of experiments employing probe molecules, researchers have explored the confined environment presented by RMs and their impact on a range of chemical reactions. These studies have shown that confinement, rather than the specific interactions with surfactants, is an important factor determining the impact of the reverse micellar environment on the chemistry.
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Affiliation(s)
- Nancy E Levinger
- Department of Chemistry, Colorado State University, Fort Collins, Colorado 80523, USA.
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188
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Middleton CT, de La Harpe K, Su C, Law YK, Crespo-Hernández CE, Kohler B. DNA excited-state dynamics: from single bases to the double helix. Annu Rev Phys Chem 2009; 60:217-39. [PMID: 19012538 DOI: 10.1146/annurev.physchem.59.032607.093719] [Citation(s) in RCA: 602] [Impact Index Per Article: 40.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Ultraviolet light is strongly absorbed by DNA, producing excited electronic states that sometimes initiate damaging photochemical reactions. Fully mapping the reactive and nonreactive decay pathways available to excited electronic states in DNA is a decades-old quest. Progress toward this goal has accelerated rapidly in recent years, in large measure because of ultrafast laser experiments. Here we review recent discoveries and controversies concerning the nature and dynamics of excited states in DNA model systems in solution. Nonradiative decay by single, solvated nucleotides occurs primarily on the subpicosecond timescale. Surprisingly, excess electronic energy relaxes one or two orders of magnitude more slowly in DNA oligo- and polynucleotides. Highly efficient nonradiative decay pathways guarantee that most excited states do not lead to deleterious reactions but instead relax back to the electronic ground state. Understanding how the spatial organization of the bases controls the relaxation of excess electronic energy in the double helix and in alternative structures is currently one of the most exciting challenges in the field.
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Affiliation(s)
- Chris T Middleton
- Department of Chemistry, The Ohio State University, Columbus, Ohio 43210, USA
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189
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Towrie M, Doorley GW, George MW, Parker AW, Quinn SJ, Kelly JM. ps-TRIR covers all the bases--recent advances in the use of transient IR for the detection of short-lived species in nucleic acids. Analyst 2009; 134:1265-73. [PMID: 19562188 DOI: 10.1039/b902108f] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Recent developments of the picosecond transient absorption infrared technique and its ability to elucidate the nature and kinetic behaviour of transient species formed upon pulsed laser excitation of nucleic acids are described.
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Affiliation(s)
- Michael Towrie
- Central Laser Facility, Science & Technology Facilities Council, Rutherford Appleton Laboratory, Harwell Science and Innovation Campus, Didcot, Oxfordshire, UK OX11 0QX
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190
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Burns LA, Murdock D, Vaccaro PH. An exploration of electronic structure and nuclear dynamics in tropolone: II. The à B12 (π∗π) excited state. J Chem Phys 2009; 130:144304. [DOI: 10.1063/1.3089722] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
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191
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Wolpert D, Schade M, Brixner T. Femtosecond midinfrared study of the photoinduced Wolff rearrangement of diazonaphthoquinone. J Chem Phys 2009; 129:094504. [PMID: 19044874 DOI: 10.1063/1.2971037] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Time-resolved vibrational femtosecond spectroscopy is employed to investigate the photoinduced Wolff rearrangement reaction of diazonaphthoquinone (DNQ) dissolved in different solvents (methanol and water). DNQ is an important compound in commercial Novolak photoresists. Upon photoexcitation the ketene intermediate appears within 300 fs, indicating that the ketene is formed in a very fast concerted process involving N(2) loss and rearrangement. The strong shift of the vibrational band, assigned to the ketene by density functional theory calculations and experimental infrared spectra, toward higher wavenumbers is attributed to vibrational cooling. The relaxation time depends on the solvent (10 ps in methanol and 3 ps in water). However, the spectroscopic data show that the indirect ketene formation via a carbene intermediate might also be involved in the reaction process contributing to the ketene formation on the 10 ps time scale.
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Affiliation(s)
- Daniel Wolpert
- Physikalisches Institut, Universitat Wurzburg, Am Hubland, 97074 Wurzburg, Germany
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192
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LI YUANZUO, LIU SHASHA, ZHAO LILI, CHEN MAODU, MA FENGCAI, DING YONG. EXCITED-STATE INTRAMOLECULAR ELECTRON TRANSFER COUPLED WITH EXCITED-STATE INTRAMOLECULAR PROTON TRANSFER IN PHOTOINDUCED ENOL TO KETO TAUTOMERIZATION. JOURNAL OF THEORETICAL & COMPUTATIONAL CHEMISTRY 2009. [DOI: 10.1142/s0219633609005246] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
In this paper, the two-dimensional (2D) site and the three-dimensional (3D) cube representations [Sun MT, J Chem Phys124: 054903, 2006] have been further developed to study the charge transfer during excited-state relaxation. With these newly developed representations, we theoretically investigate the excited-state intramolecular electron transfer (ESIET) in enol excited-state geometry relaxation, and ESIET coupled with excited-state intramolecular proton transfer (ESIPT) in phototautomerization (in enol to keto transformation). The energy levels of highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) of HBODC in enol and keto absorption and fluorescence are compared to understand photoinduced ESIET and ESIPT process. The excited regions of molecule (where arrangement of electron density takes place during excited-state relaxation) are located with 2D site representation. 3D cube representations visualize the character of charge transfer (CT) in those regions. Results of the research indicate that the ability of charge transfer during enol excited-state geometry relaxation is much stronger than that in phototautomerization.
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Affiliation(s)
- YUANZUO LI
- School of Physics and Optoelectronic Technology, and, College of Advanced Science and Technology, Dalian University of Technology, Dalian 116024, P. R. China
| | - SHASHA LIU
- School of Physics and Optoelectronic Technology, and, College of Advanced Science and Technology, Dalian University of Technology, Dalian 116024, P. R. China
| | - LILI ZHAO
- Department of Physics, Liaoning University, Shenyang 110036, P. R. China
| | - MAODU CHEN
- School of Physics and Optoelectronic Technology, and, College of Advanced Science and Technology, Dalian University of Technology, Dalian 116024, P. R. China
| | - FENGCAI MA
- Department of Physics, Liaoning University, Shenyang 110036, P. R. China
| | - YONG DING
- Department of Physics, Liaoning University, Shenyang 110036, P. R. China
- Department of Physics, Peking University, Beijing 100087, P. R. China
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193
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Pensack RD, Banyas KM, Barbour LW, Hegadorn M, Asbury JB. Ultrafast vibrational spectroscopy of charge-carrier dynamics in organic photovoltaic materials. Phys Chem Chem Phys 2009; 11:2575-91. [DOI: 10.1039/b817113k] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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194
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Schmierer T, Schreier WJ, Koller FO, Schrader TE, Gilch P. Impact of vibrational excitation on the kinetics of a nascent ketene. Phys Chem Chem Phys 2009; 11:11596-607. [DOI: 10.1039/b915451e] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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195
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Mohammed O, Adamczyk K, Banerji N, Dreyer J, Lang B, Nibbering E, Vauthey E. Direct Femtosecond Observation of Tight and Loose Ion Pairs upon Photoinduced Bimolecular Electron Transfer. Angew Chem Int Ed Engl 2008. [DOI: 10.1002/ange.200803164] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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196
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Mohammed O, Adamczyk K, Banerji N, Dreyer J, Lang B, Nibbering E, Vauthey E. Direct Femtosecond Observation of Tight and Loose Ion Pairs upon Photoinduced Bimolecular Electron Transfer. Angew Chem Int Ed Engl 2008; 47:9044-8. [DOI: 10.1002/anie.200803164] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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197
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Zhao GJ, Han KL. Time-dependent density functional theory study on hydrogen-bonded intramolecular charge-transfer excited state of 4-dimethylamino-benzonitrile in methanol. J Comput Chem 2008; 29:2010-7. [PMID: 18351604 DOI: 10.1002/jcc.20957] [Citation(s) in RCA: 253] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
The time-dependent density functional theory (TDDFT) method was carried out to investigate the hydrogen-bonded intramolecular charge-transfer (ICT) excited state of 4-dimethylaminobenzonitrile (DMABN) in methanol (MeOH) solvent. We demonstrated that the intermolecular hydrogen bond C[triple bond]N...H-O formed between DMABN and MeOH can induce the C[triple bond]N stretching mode shift to the blue in both the ground state and the twisted intramolecular charge-transfer (TICT) state of DMABN. Therefore, the two components at 2091 and 2109 cm(-1) observed in the time-resolved infrared (TRIR) absorption spectra of DMABN in MeOH solvent were reassigned in this work. The hydrogen-bonded TICT state should correspond to the blue-side component at 2109 cm(-1), whereas not the red-side component at 2091 cm(-1) designated in the previous study. It was also demonstrated that the intermolecular hydrogen bond C[triple bond]N...H-O is significantly strengthened in the TICT state. The intermolecular hydrogen bond strengthening in the TICT state can facilitate the deactivation of the excited state via internal conversion (IC), and thus account for the fluorescence quenching of DMABN in protic solvents. Furthermore, the dynamic equilibrium of these electronically excited states is explained by the hydrogen bond strengthening in the TICT state.
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Affiliation(s)
- Guang-Jiu Zhao
- State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, Liaoning, China
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198
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Ghosh A, Smits M, Bredenbeck J, Dijkhuizen N, Bonn M. Femtosecond time-resolved and two-dimensional vibrational sum frequency spectroscopic instrumentation to study structural dynamics at interfaces. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2008; 79:093907. [PMID: 19044428 DOI: 10.1063/1.2982058] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
We present a novel setup to elucidate the dynamics of interfacial molecules specifically, using surface-selective femtosecond vibrational spectroscopy. The approach relies on a fourth-order nonlinear optical interaction at the interface. In the experiments, interfacial molecules are vibrationally excited by an intense, tunable femtosecond midinfrared (2500-3800 cm(-1)) pump pulse, resonant with the molecular vibrations. The effect of the excitation and the subsequent relaxation to the equilibrium state are probed using broadband infrared+visible sum frequency generation (SFG) light, which provides the transient vibrational spectrum of interfacial molecules specifically. This IR pump-SFG probe setup has the ability to measure both vibrational population lifetimes as well as the vibrational coupling between different chemical moieties at interfaces. Vibrational lifetimes of interfacial molecules are determined in one-dimensional pump-SFG probe experiments, in which the response is monitored as a function of the delay between the pump and probe pulses. Vibrational coupling between molecular groups is determined in two-dimensional pump-SFG probe experiments, which monitor the response as a function of pump and probe frequencies at a fixed delay time. To allow for one setup to perform these multifaceted experiments, we have implemented several instrumentation techniques described here. The detection of the spectrally resolved differential SFG signal using a combination of a charge-coupled device camera and a piezocontrolled optical scanner, computer-controlled Fabry-Perot etalons to shape and scan the IR pump pulse and the automated sample dispenser and sample trough height corrector are some of the novelties in this setup.
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Affiliation(s)
- Avishek Ghosh
- FOM, Institute for Atomic and Molecular Physics (AMOLF), Kruislaan 407, 1098 SJ Amsterdam, The Netherlands
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Staudt H, Köhler T, Lorenz L, Neumann K, Verhoefen MK, Wachtveitl J. Time resolved spectroscopy on Pigment Yellow 101 in solid state. Chem Phys 2008. [DOI: 10.1016/j.chemphys.2007.10.038] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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