Transient isomers in the photodissociation of bromoiodomethane

Marcellini, Moreno; Nasedkin, Alexandr; Zietz, Burkhard; Petersson, Jonas; Vincent, Jonathan; Palazzetti, Federico; Malmerberg, Erik; Kong, Qingyu; Wulff, Michaël; Spoel, David van der; Neutze, Richard; Davidsson, Jan

doi:10.1063/1.5005595

Cited by 6 publications

(10 citation statements)

References 112 publications

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“…A powerful method to disentangle the electronic and nuclear motions of 3d transition metal complexes during ultrafast nonadiabatic processes is time-resolved 1s-2p (Ka) and 1s-3p (Kβ) X-ray Emission Spectroscopy (XES) [10][11][12][13][14] combined with Wide Angle X-ray Scattering (WAXS) [15][16][17][18][19][20][21][22][23]. These experiments have been utilized to assign the electronic and structural motions during excited state dynamics [24][25][26] and to project the locations of conical intersections between excited state potential energy surfaces onto critical structural coordinates [27].…”

Section: Introductionmentioning

confidence: 99%

Vibrational wavepacket dynamics in Fe carbene photosensitizer determined with femtosecond X-ray emission and scattering

et al. 2020

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The non-equilibrium dynamics of electrons and nuclei govern the function of photoactive materials. Disentangling these dynamics remains a critical goal for understanding photoactive materials. Here we investigate the photoinduced dynamics of the [Fe(bmip)2]2+ photosensitizer, where bmip = 2,6-bis(3-methyl-imidazole-1-ylidine)-pyridine, with simultaneous femtosecond-resolution Fe Kα and Kβ X-ray emission spectroscopy (XES) and X-ray solution scattering (XSS). This measurement shows temporal oscillations in the XES and XSS difference signals with the same 278 fs period oscillation. These oscillations originate from an Fe-ligand stretching vibrational wavepacket on a triplet metal-centered (3MC) excited state surface. This 3MC state is populated with a 110 fs time constant by 40% of the excited molecules while the rest relax to a 3MLCT excited state. The sensitivity of the Kα XES to molecular structure results from a 0.7% average Fe-ligand bond length shift between the 1 s and 2p core-ionized states surfaces.

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Section: Introductionmentioning

confidence: 99%

Vibrational wavepacket dynamics in Fe carbene photosensitizer determined with femtosecond X-ray emission and scattering

et al. 2020

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“…For example, I 3 − adopts solvent-dependent molecular structures, a symmetric structure in acetonitrile and an asymmetric structure in water. In Type 2, part of the reaction pathway is altered depending on the solvent, as can be seen in the photoreactions of CH 2 I 2 [ 6 , 13 ], CH 2 IBr [ 14 ], CHBr 3 [ 30 ], CHI 3 [ 5 , 15 ], and HgI 2 [ 55 , 56 ]. In the case of the photodissociation of CHI 3 , an isomerization pathway leading to the formation of iso-CHI 2 −I is active in cyclohexane, whereas the pathway is inactive in methanol.…”

Section: Resultsmentioning

confidence: 99%

“…The photoexcitation of haloalkanes at ultraviolet wavelengths induces an electronic transition corresponding to the n → σ* transition of a carbon–halogen bond, leading to the dissociation of halogen atoms [ 1 , 2 ]. This photoinduced dissociation has served as an excellent model system to study reaction dynamics due to their simple molecular structures [ 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9 , 10 , 11 , 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 , 22 , 23 , 24 , 25 , 26 , 27 , 28 , 29 , 30 , 31 , 32 , 33 , 34 , 35 , 36 , 37 , 38 , 39 , 40 , 41 , 42 , 43 , 44 , 45 , 46 , 47 , 48 ]. The structures of reaction intermediates of haloalkane photodissociation are relevant to the stereochemical control of the products of the halogen elimination reaction of haloalkanes.…”

Section: Introductionmentioning

confidence: 99%

“…To investigate the reaction dynamics and structures of reaction intermediates, and subtle effects of atomic substitution, the molecular structures of reacting molecules must be characterized. In this regard, time-resolved X-ray liquidography (TRXL), also known as time-resolved X-ray solution scattering, is an excellent technique because it can be used to both provide global reaction pathways of chemical reactions and reveal the structures of transient intermediates in the liquid solution phase [ 5 , 6 , 7 , 8 , 9 , 10 , 11 , 12 , 13 , 14 , 15 , 16 , 51 , 52 , 53 , 54 , 55 , 56 , 57 , 58 , 59 , 60 , 61 , 62 , 63 , 64 , 65 , 66 , 67 , 68 , 69 , 70 , 71 , 72 , 73 , 74 , 75 ]. Thus far, TRXL has been used for studying the structural dynamics of a wide variety of systems spanning diatomic molecules, organometallic complexes, proteins, and nanoparticles in the solution phase [ 5 , 6 , 7 , 8 , 9 , 10 , 11 , 12 , 13 , 14 , 15 , 16 , 51 , 52 ...…”

Section: Introductionmentioning

confidence: 99%

“…In this regard, time-resolved X-ray liquidography (TRXL), also known as time-resolved X-ray solution scattering, is an excellent technique because it can be used to both provide global reaction pathways of chemical reactions and reveal the structures of transient intermediates in the liquid solution phase [5][6][7][8][9][10][11][12][13][14][15][16]. Thus far, TRXL has been used for studying the structural dynamics of a wide variety of systems spanning diatomic molecules, organometallic complexes, proteins, and nanoparticles in the solution phase [5][6][7][8][9][10][11][12][13][14][15][16].…”

Section: Introductionmentioning

confidence: 99%

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

Lee

Eom

et al. 2021

IJMS

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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.

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Femtosecond X-ray Liquidography Visualizes Wavepacket Trajectories in Multidimensional Nuclear Coordinates for a Bimolecular Reaction

et al. 2021

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Conspectus Vibrational wavepacket motions on potential energy surfaces are one of the critical factors that determine the reaction dynamics of photoinduced reactions. The motions of vibrational wavepackets are often discussed in the interpretation of observables measured with various time-resolved vibrational or electronic spectroscopies but mostly in terms of the frequencies of wavepacket motions, which are approximated by normal modes, rather than the actual positions of the wavepacket. Although the time-dependent positions (that is, the trajectory) of wavepackets are hypothesized or drawn in imagined or calculated potential energy surfaces, it is not trivial to experimentally determine the trajectory of wavepackets, especially in multidimensional nuclear coordinates for a polyatomic molecule. Recently, we performed a femtosecond X-ray liquidography (solution scattering) experiment on a gold trimer complex (GTC), [Au(CN)2 –]3, in water at X-ray free-electron lasers (XFELs) and elucidated the time-dependent positions of vibrational wavepackets from the Franck–Condon region to equilibrium structures on both excited and ground states in the course of the formation of covalent bonds between gold atoms. Bond making is an essential process in chemical reactions, but it is challenging to keep track of detailed atomic movements associated with bond making because of its bimolecular nature that requires slow diffusion of two reaction parties to meet each other. Bond formation in the solution phase has been elusive because the diffusion of the reactants limits the reaction rate of a bimolecular process, making it difficult to initiate and track the bond-making processes with an ultrafast time resolution. In principle, if the bimolecular encounter can be controlled to overcome the limitation caused by diffusion, the bond-making processes can be tracked in a time-resolved manner, providing valuable insight into the bimolecular reaction mechanism. In this regard, GTC offers a good model system for studying the dynamics of bond formation in solution. Au(I) atoms in GTC exhibit a noncovalent aurophilic interaction, making GTC an aggregate complex without any covalent bond. Upon photoexcitation of GTC, an electron is excited from an antibonding orbital to a bonding orbital, leading to the formation of covalent bonds among Au atoms. Since Au atoms in the ground state of GTC are located in close proximity within the same solvent cage, the formation of Au–Au covalent bonds occurs without its reaction rate being limited by diffusion through the solvent. Femtosecond time-resolved X-ray liquidography (fs-TRXL) data revealed that the ground state has an asymmetric bent structure. From the wavepacket trajectory determined in three-dimensional nuclear coordinates (two internuclear distances and one bond angle), we found that two covalent bonds are formed between three Au atoms of GTC asynchronously. Specifically, one covalent bond is formed first for the shorter Au–Au pair (of the asymmetric and bent ground-state structure) in 35 fs,...

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Transient isomers in the photodissociation of bromoiodomethane

Cited by 6 publications

References 112 publications

Vibrational wavepacket dynamics in Fe carbene photosensitizer determined with femtosecond X-ray emission and scattering

Vibrational wavepacket dynamics in Fe carbene photosensitizer determined with femtosecond X-ray emission and scattering

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

Femtosecond X-ray Liquidography Visualizes Wavepacket Trajectories in Multidimensional Nuclear Coordinates for a Bimolecular Reaction

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