Vibrational Relaxation Dynamics of the Core and Outer Part of Proton-Hydration Clusters

Sofronov, Oleksandr O.; Bakker, Huib J.

doi:10.1021/acs.jpcb.9b02067

Cited by 4 publications

(5 citation statements)

References 35 publications

(85 reference statements)

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“…In contrast, deuteration slows the relaxation dynamics by about twice. Such an effect suggests that the relaxation involves Förster energy transfer, which exists in water systems where OH modes of water are closely overlapped (45,58). In the literature, the energy transfer rate was also determined to be about 2.3 times more efficient for the OH band than the OD band due to the difference in transition dipole moments (59), which agrees with our experimental observation.…”

Section: Resultssupporting

confidence: 90%

Spatially dependent H-bond dynamics at interfaces of water/biomimetic self-assembled lattice materials

Wang

Wagner

Chen

et al. 2020

Proc. Natl. Acad. Sci. U.S.A.

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Understanding hydrogen-bond interactions in self-assembled lattice materials is crucial for preparing such materials, but the role of hydrogen bonds (H bonds) remains unclear. To gain insight into H-bond interactions at the materials’ intrinsic spatial scale, we investigated ultrafast H-bond dynamics between water and biomimetic self-assembled lattice materials (composed of sodium dodecyl sulfate and β-cyclodextrin) in a spatially resolved manner. To accomplish this, we developed an infrared pump, vibrational sum-frequency generation (VSFG) probe hyperspectral microscope. With this hyperspectral imaging method, we were able to observe that the primary and secondary OH groups of β-cyclodextrin exhibit markedly different dynamics, suggesting distinct H-bond environments, despite being separated by only a few angstroms. We also observed another ultrafast dynamic reflecting a weakening and restoring of H bonds between bound water and the secondary OH of β-cyclodextrin, which exhibited spatial uniformity within self-assembled domains, but heterogeneity between domains. The restoration dynamics further suggest heterogeneous hydration among the self-assembly domains. The ultrafast nature and meso- and microscopic ordering of H-bond dynamics could contribute to the flexibility and crystallinity of the material––two critically important factors for crystalline lattice self-assemblies––shedding light on engineering intermolecular interactions for self-assembled lattice materials.

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Section: Resultssupporting

confidence: 90%

Spatially dependent H-bond dynamics at interfaces of water/biomimetic self-assembled lattice materials

Wang

Wagner

Chen

et al. 2020

Proc. Natl. Acad. Sci. U.S.A.

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“…This part of the spectrum corresponds to the OH-stretch vibrations of the core of the proton hydration structures, that is, OHvibrations for which the H atom carries a significant fraction of the excess positive proton charge. 40 Since at very short delay times we already observe a strong heating signal from water molecules (Figure 2), we conclude that excited OH-stretch vibrations at 2600 cm −1 relax ultrafast within the time resolution (∼100 fs) of the experiment. This means that the transient spectra at frequencies <2800 cm −1 are not due to the population of the excited v = 1 state of the OH vibrations but rather reflect a local heating effect on the absorption spectrum of the proton hydration structure.…”

Section: ■ Resultsmentioning

confidence: 51%

“…This part of the spectrum corresponds to the OH-stretch vibrations of the core of the proton hydration structures, that is, OH-vibrations for which the H atom carries a significant fraction of the excess positive proton charge. 40 …”

Section: Resultsmentioning

confidence: 99%

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Slow Proton Transfer in Nanoconfined Water

Sofronov

Bakker

2020

ACS Cent. Sci.

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The transport of protons in nanoconfined environments, such as in nanochannels of biological or artificial proton conductive membranes, is essential to chemistry, biology, and nanotechnology. In water, proton diffusion occurs by hopping of protons between water molecules. This process involves the rearrangement of many hydrogen bonds and as such can be strongly affected by nanoconfinement. We study the vibrational and structural dynamics of hydrated protons in water nanodroplets stabilized by a cationic surfactant using polarization-resolved femtosecond infrared transient absorption spectroscopy. We determine the time scale of proton hopping in the center of the water nanodroplets from the dynamics of the anisotropy of the transient absorption signals. We find that in small nanodroplets with a diameter <4 nm, proton hopping is more than 10 times slower than in bulk water. Even in relatively large nanodroplets with a diameter of ∼7 nm, we find that the rate of proton hopping is slowed by ∼4 times compared with bulk water.

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“…FT-IR spectra of LFP and LSP are shown in Figure 1 A; no significant differences were observed, indicating that the structures of the two polysaccharides extracted by water extraction were similar. The strong absorption peak at 3400 cm −1 indicates O-H stretching vibration [ 18 ]. Bands in the 3000–2800 cm −1 region represent C-H stretching and bending vibrations, including CH, CH 2 , and CH 3 [ 19 ].…”

Section: Results and Analysismentioning

confidence: 99%

Lotus-Flower- and Lotus-Seedpod-Derived Polysaccharide: Structural Characterization and Biological Activity

Zhang,

Wang,

Zeng

et al. 2023

Polymers

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Lotus flower polysaccharide (LFP) and lotus seedpod polysaccharide (LSP) were separated by water extract–alcohol precipitation, and their structures and biological activities were investigated. The results of monosaccharide composition showed that LFP and LSP were composed of nine monosaccharides, fucose, rhamnose, arabinose, glucose, galactose, mannose, fructose, galacturonic acid, and glucuronic acid, with the molar percentages of 0.18: 0.43: 2.26: 45.22: 32.14: 4.28: 8.20: 6.28: 1.01 and 2.70: 1.02: 8.15: 45.63: 20.63: 1.44: 2.59: 16.45. LSP and LFP exhibited molecular weights of 9.37 × 104 Da and 1.24 × 106 Da, respectively. SEM showed that LFP and LSP have similar structures; XRD analysis showed that both polysaccharides had crystalline structure and amorphous structure. The results of ABTS+, DPPH, hydroxyl radical scavenging experiment, and a reducing power experiment showed that LFP and LSP had good antioxidant capacity. Cell viability findings showed that polysaccharide concentrations of lotus flower and lotus seedpod could enhance cellular proliferation ranging from 25 to 400 μg/mL without cytotoxicity. By inducing the production of crucial proteins in the TLR4/NF-κB pathway, LFP and LSP were able to induce autophagy in RAW264.7, according to the results of the RT-PCR and Western blotting assays.

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Vibrational Relaxation Dynamics of the Core and Outer Part of Proton-Hydration Clusters

Cited by 4 publications

References 35 publications

Spatially dependent H-bond dynamics at interfaces of water/biomimetic self-assembled lattice materials

Spatially dependent H-bond dynamics at interfaces of water/biomimetic self-assembled lattice materials

Slow Proton Transfer in Nanoconfined Water

Lotus-Flower- and Lotus-Seedpod-Derived Polysaccharide: Structural Characterization and Biological Activity

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