Femtochemistry and Femtobiology: The New Age

Chergui, Majed

doi:10.1002/1439-7641(20020816)3:8<713::aid-cphc713>3.0.co;2-f

Cited by 6 publications

(5 citation statements)

References 39 publications

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“…We mention this example here not only for historical reasons but also because Mössbauer spectroscopy is an extremely powerful tool used in structural research, which may even be viewed as an analogue to XAS in nuclear spectroscopy. We feel its extension to time-resolved studies, especially in the short time domain, could open a new area of research in structural dynamics …”

Section: Time-resolved Xas Studiesmentioning

confidence: 99%

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Ultrafast X-ray Absorption Spectroscopy

2004

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Section: Time-resolved Xas Studiesmentioning

confidence: 99%

“…We feel its extension to time-resolved studies, especially in the short time domain, could open a new area of research in structural dynamics. 167 In the following, we review the studies that were carried out using the pulsed nature of the X-ray source, descending from the microsecond time domain to the femtosecond time scale.…”

Section: Time-resolved Xas Studiesmentioning

confidence: 99%

Ultrafast X-ray Absorption Spectroscopy

2004

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“…Over the last two decades, interest in studying photophysical properties of several classes of drugs has grown continuously. − Recent progress in ultrafast spectroscopy provided new tools to investigate the very first events occurring after photon absorption. , Knowledge about light-induced processes and excited-state reactions is no longer limited to conventional examination of final products, but detailed relaxation pathways and reaction timing are accessible. In addition to the insight into fundamental scientific problems (e.g., proton transfer or isomerism), the obtained data could be useful for a better drug design or in resolving practical issues such as storage photostability or phototoxicity of drugs.…”

Section: Introductionmentioning

confidence: 99%

Femtosecond Dynamics of Piroxicam Structures in Solutions

Gil

Douhal

2008

J. Phys. Chem. A

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We report on studies of femtosecond dynamics of a nonsteroidal anti-inflammatory drug, piroxicam (1), in water at three different pHs and for comparison in two aprotic solvents. An ultrafast excited-state proton-transfer (ESIPT) process takes place in neutral and cationic enol-type structures. Femtosecond emission and transient absorption experiments show that this reaction is barrierless, and the proton-transferred keto tautomer is formed in less than 100 fs in both organic solvents and acidic water. In neutral and alkaline water, the ESIPT is not present because of the prevalence of the anion structures at the ground state. For the excited anions (pH = 7, 11) and formed keto cations (pH approximately 3), an intramolecular charge-transfer process takes place in times shorter than 0.3 ps. The formed structures have a fluorescence lifetime of approximately 2-5 ps, depending on pH. In contrast, the internal twisting motion in organic solvents is slower (approximately 0.5-1 ps) and gives rotamers with lifetimes of tens of picoseconds. These results clearly show strong interactions of 1 with water, significantly distinct from those present in organic aprotic solvents. We believe that the results are important for a better understanding on short time interactions of drugs with their environment.

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“…radiation damage, low signal to noise ratio, ultrafast data acquisition) must be overcome along this perspective as in the case of the "single molecule" X-ray diffraction experiment, which is under development at the X-FEL laboratories [61,62]. Thus, in the near future, the possibility to monitor subtle differences due to light induced or X-ray induced changes into the metal center of a protein, will put XANES spectroscopy applied to biological samples, even more into the hot spot [63].…”

Section: Resultsmentioning

confidence: 99%