scholarly journals Structural Dynamics of C2F4I2 in Cyclohexane Studied via Time-Resolved X-ray Liquidography

2021 ◽  
Vol 22 (18) ◽  
pp. 9793
Author(s):  
Jain Gu ◽  
Seonggon Lee ◽  
Seunghwan Eom ◽  
Hosung Ki ◽  
Eun Hyuk Choi ◽  
...  
Keyword(s):  
Reaction Dynamics ◽  
Molecular Structures ◽  
Solution Phase ◽  
Reaction Pathways ◽  
Time Resolved ◽  
Solvent Interactions ◽  
X Ray ◽  
Exchange Correlation ◽  
Solvent Dependence ◽  
Halogen Elimination

The halogen elimination of 1,2-diiodoethane (C2H4I2) and 1,2-diiodotetrafluoroethane (C2F4I2) serves as a model reaction for investigating the influence of fluorination on reaction dynamics and solute–solvent interactions in solution-phase reactions. While the kinetics and reaction pathways of the halogen elimination reaction of C2H4I2 were reported to vary substantially depending on the solvent, the solvent effects on the photodissociation of C2F4I2 remain to be explored, as its reaction dynamics have only been studied in methanol. Here, to investigate the solvent dependence, we conducted a time-resolved X-ray liquidography (TRXL) experiment on C2F4I2 in cyclohexane. The data revealed that (ⅰ) the solvent dependence of the photoreaction of C2F4I2 is not as strong as that observed for C2H4I2, and (ⅱ) the nongeminate recombination leading to the formation of I2 is slower in cyclohexane than in methanol. We also show that the molecular structures of the relevant species determined from the structural analysis of TRXL data provide an excellent benchmark for DFT calculations, especially for investigating the relevance of exchange-correlation functionals used for the structural optimization of haloalkanes. This study demonstrates that TRXL is a powerful technique to study solvent dependence in the solution phase.

scholarly journals Time-Resolved Macromolecular Crystallography at Pulsed X-ray Sources

2019 ◽  
Vol 20 (6) ◽  
pp. 1401 ◽  
Author(s):  
Marius Schmidt
Keyword(s):  
Structural Biology ◽  
Free Electron ◽  
Reaction Dynamics ◽  
X Rays ◽  
Free Electron Lasers ◽  
Macromolecular Crystallography ◽  
Time Resolved ◽  
X Ray ◽  
Methodological Aspects

The focus of structural biology is shifting from the determination of static structures to the investigation of dynamical aspects of macromolecular function. With time-resolved macromolecular crystallography (TRX), intermediates that form and decay during the macromolecular reaction can be investigated, as well as their reaction dynamics. Time-resolved crystallographic methods were initially developed at synchrotrons. However, about a decade ago, extremely brilliant, femtosecond-pulsed X-ray sources, the free electron lasers for hard X-rays, became available to a wider community. TRX is now possible with femtosecond temporal resolution. This review provides an overview of methodological aspects of TRX, and at the same time, aims to outline the frontiers of this method at modern pulsed X-ray sources.

scholarly journals Determination of Excited State Molecular Structures from Time-Resolved Gas-Phase X-Ray Scattering

2020 ◽  
Author(s):  
Haiwang Yong ◽  
Andrés Moreno Carrascosa ◽  
Lingyu Ma ◽  
Brian Stankus ◽  
Michael P Minitti ◽  
...  
Keyword(s):  
Excited State ◽  
Gas Phase ◽  
Electronic States ◽  
Molecular Structures ◽  
Excited Electronic States ◽  
Comprehensive Investigation ◽  
Time Resolved ◽  
X Ray ◽  
X Ray Scattering

We present a comprehensive investigation of a recently introduced method to determine transient structures of molecules in excited electronic states with sub-Ångstrom resolution from time-resolved gas-phase scattering signals. The method,...

Ultrafast X-ray diffraction in liquid, solution and gas: present status and future prospects

2010 ◽  
Vol 66 (2) ◽  
pp. 270-280 ◽  
Author(s):  
Jeongho Kim ◽  
Kyung Hwan Kim ◽  
Jae Hyuk Lee ◽  
Hyotcherl Ihee
Keyword(s):  
Single Molecule ◽  
Reaction Dynamics ◽  
Liquid Solution ◽  
Substantial Improvement ◽  
Photon Flux ◽  
Solvation Dynamics ◽  
Structural Transitions ◽  
X Ray Diffraction ◽  
Time Resolved ◽  
X Ray

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.

scholarly journals Estimating signal and noise of time-resolved X-ray solution scattering data at synchrotrons and XFELs

2020 ◽  
Vol 27 (3) ◽  
pp. 633-645
Author(s):  
Jungmin Kim ◽  
Jong Goo Kim ◽  
Hosung Ki ◽  
Chi Woo Ahn ◽  
Hyotcherl Ihee
Keyword(s):  
Quantum Noise ◽  
Structural Information ◽  
Signal To Noise Ratio ◽  
Liquid Solution ◽  
Solution Phase ◽  
Scattering Data ◽  
Time Resolved ◽  
X Ray ◽  
The Future ◽  
The Difference

Elucidating the structural dynamics of small molecules and proteins in the liquid solution phase is essential to ensure a fundamental understanding of their reaction mechanisms. In this regard, time-resolved X-ray solution scattering (TRXSS), also known as time-resolved X-ray liquidography (TRXL), has been established as a powerful technique for obtaining the structural information of reaction intermediates and products in the liquid solution phase and is expected to be applied to a wider range of molecules in the future. A TRXL experiment is generally performed at the beamline of a synchrotron or an X-ray free-electron laser (XFEL) to provide intense and short X-ray pulses. Considering the limited opportunities to use these facilities, it is necessary to verify the plausibility of a target experiment prior to the actual experiment. For this purpose, a program has been developed, referred to as S-cube, which is short for a Solution Scattering Simulator. This code allows the routine estimation of the shape and signal-to-noise ratio (SNR) of TRXL data from known experimental parameters. Specifically, S-cube calculates the difference scattering curve and the associated quantum noise on the basis of the molecular structure of the target reactant and product, the target solvent, the energy of the pump laser pulse and the specifications of the beamline to be used. Employing a simplified form for the pair-distribution function required to calculate the solute–solvent cross term greatly increases the calculation speed as compared with a typical TRXL data analysis. Demonstrative applications of S-cube are presented, including the estimation of the expected TRXL data and SNR level for the future LCLS-II HE beamlines.

scholarly journals Exploring reaction dynamics in lithium–sulfur batteries by time-resolved operando sulfur K-edge X-ray absorption spectroscopy

2019 ◽  
Vol 55 (34) ◽  
pp. 4993-4996 ◽  
Author(s):  
Enyue Zhao ◽  
Junyang Wang ◽  
Feng Li ◽  
Zheng Jiang ◽  
Xiao-Qing Yang ◽  
...  
Keyword(s):  
Absorption Spectroscopy ◽  
Reaction Dynamics ◽  
Conversion Process ◽  
Time Resolved ◽  
X Ray ◽  
Lithium Sulfur Batteries ◽  
X Ray Absorption ◽  
Sulfur Electrode ◽  
Lithium Sulfur

The multistep kinetic-determining conversion process of a sulfur electrode is directly revealed through time-resolved operando X-ray absorption spectroscopy.

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