Unter dem Ab‐initio‐Mikroskop: molekulare Beiträge in der Femtosekunden‐Stokes‐Verschiebung eines Reichardt‐Farbstoffs

Allolio, Christoph; Sajadi, Mohsen; Érnsting, N. P.; Sebastiani, Daniel

doi:10.1002/ange.201204532

Cited by 4 publications

(2 citation statements)

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“…The self-consistent field (SCF) convergence was set to 6 10 À7 a.u. [32][33][34] We used the deuteron mass for the hydrogen atoms and a time step of 1 fs. The system was thermostatically controlled to 350 K by using a CSVR thermostat [31] with a time constant of 100 fs.…”

Section: Computational Detailsmentioning

confidence: 99%

“…The increased temperature with respect to standard conditions was meant to compensate for the overstructuring of water. [32][33][34] We used the deuteron mass for the hydrogen atoms and a time step of 1 fs. All ab initio simulations were performed using the CP2K code [35] .Despite the use of a stochastical thermostat in the ab initio trajectory, diffusion coefficients and power spectra were not expected to be strongly affected by thermostatic control.…”

Section: Computational Detailsmentioning

confidence: 99%

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Ab Initio H₂O in Realistic Hydrophilic Confinement

et al. 2014

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A protocol for the ab initio construction of a realistic cylindrical pore in amorphous silica, serving as a geometric nanoscale confinement for liquids and solutions, is presented. Upon filling the pore with liquid water at different densities, the structure and dynamics of the liquid inside the confinement can be characterized. At high density, the pore introduces long-range oscillations into the water density profile, which makes the water structure unlike that of the bulk across the entire pore. The tetrahedral structure of water is also affected up to the second solvation shell of the pore wall. Furthermore, the effects of the confinement on hydrogen bonding and diffusion, resulting in a weakening and distortion of the water structure at the pore walls and a slowdown in diffusion, are characterized.

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Section: Computational Detailsmentioning

confidence: 99%

Section: Computational Detailsmentioning

confidence: 99%

Ab Initio H₂O in Realistic Hydrophilic Confinement

et al. 2014

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Ionische Flüssigkeit mit eingebautem Farbstoff zeigt große Stokes‐Verschiebung

et al. 2017

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Eine Farbstoffsonde wurde in protonierter Form als Kation in eine ionische Flüssigkeit (IL) implementiert. Die Farbstoff‐IL N‐Methyl‐6‐hydroxychinolinium‐bis(trifluormethylsulfonyl)imid [6MQc][NTf2] wurde mittels NMR‐, ATR‐IR‐ und Röntgenkristallstrukturanalyse charakterisiert. Die Fluoreszenzbande der reinen Farbstoff‐IL zeigt eine große Stokes‐Verschiebung (Δλ=116 nm). In Acetonitril wurde eine Quantenausbeute von φF=0.56 ermittelt. In Abhängigkeit vom Lösungsmittel wird eine charakteristische Verschiebung der Emissionsbande beobachtet. Im Vergleich zur reinen Farbstoff‐IL (467 nm) wurde in Lösung mit anderen ionischen Flüssigkeiten, Acetonitril und THF eine bathochrome Verschiebung um 28 nm beobachtet. In stärker polaren Lösungsmitteln sind die Fluoreszenzsignale zu 650 nm stark rotverschoben, was auf einen Protonentransfer zum Lösungsmittel im angeregten Zustand schließen lässt. Dadurch wird ein weiterer Anwendungsbereich des 6MQc‐Bausteins als Photosäure aufgezeigt.

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Large Stokes Shift Ionic‐Liquid Dye

et al. 2017

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Abstract:We have incorporated the dye N-methyl-6-oxyquinolone [6MQz] in its protonated form as acation into an ionic liquid (IL) and thus to synthesize an IL dye.T he IL dye N-methyl-6-hydroxyquinolinium bis(trifluoromethylsulfonyl) imide [6MQc][NTf 2 ]w as characterized by NMR, ATRI R spectroscopya nd X-ray crystallography.T he fluorescence of the IL dye has al arge Stokes shift of Dl = 116 nm and aq uantum yield of f F = 0.56 in acetonitrile.C haracteristic solvent dependent shifts can be detected in the emission spectra. In other ILs,acetonitrile and THF we observe abathochromic shift of up to 28 nm compared to the pure IL dye at 467 nm. Forstronger polar solvents the fluorescence signals are strongly red-shifted to 650 nm indicating proton transfer to the solvent molecules in the excited state.T his underlines the importance of the IL building block [ MQc] + as photo acid.Fluorescent dyes are important tools in many branches of chemistry related sciences,s uch as biological chemistry, [1][2][3][4][5][6][7][8] materials science, [9][10][11] or solar-energy conversion. [12,13] Attractive fluorescent dyes are characterized by their extended spectral range,h igh emission quantum yields,p hotostability and good solubility in the solvent. Thef luorescent dye N-methyl-6-oxyquinolone [6MQz] was used for studying solvation phenomena. Thec olor of this solvatochromatic dye molecule depends strongly on the polarity of the surrounding,a st he permanent dipole moments strongly change upon excitation from the ground to the excited state.T hus [6MQz] has been used as dye for understanding solvation processes and proton transfer to solvents. [14][15][16][17][18][19][20][21][22] In some cases the polarity probe was incorporated into biomolecules such as sugars or enzymes for probing the chemical environment and providing biocompatibility. [10,11,18,19] Whereas other dyes have been extensively applied to probe the polarity of ionic liquids,t he protonated form of [6MQz] has never been used as moiety of an ionic liquid itself. [23,24] Thus,t he goal of our work was to incorporate the dye N-methyl-6-oxyquinolone [6MQz] in its protonated form as acation into an ionic liquid (IL) and thus to synthesize an IL dye.T he resulting ionic liquid dye N-methyl-6-hydroxyquinolinium bis(trifluoromethylsulfonyl) imide ]involves anion metathesis reaction and is shown in Scheme 1. Initial N-methyl-6-hydroxyquinolinium iodide was prepared using ak nown procedure which is also described in the Supporting Information (SI0). [25,26] Then, equimolar amounts of N-methyl-6-hydroxyquinolinium iodide (287 mg, 1mmol) and silver bis(trifluoromethylsulfonyl)imide (388 mg, 1mmol) were dissolved in 15 mL water each. Thet wo solutions were combined and the reaction mixture was stirred for 15 min. Silver iodide,which precipitates instantly,was filtered off and discarded. Them other liquor was removed on ar otary evaporator and the residue was dissolved in 25 mL ethanol to carry out ah ot-filtration with activated charcoal. After filtration, the solvent wa...

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Unter dem Ab‐initio‐Mikroskop: molekulare Beiträge in der Femtosekunden‐Stokes‐Verschiebung eines Reichardt‐Farbstoffs

Cited by 4 publications

References 40 publications

Ab Initio H₂O in Realistic Hydrophilic Confinement

Ab Initio H₂O in Realistic Hydrophilic Confinement

Ionische Flüssigkeit mit eingebautem Farbstoff zeigt große Stokes‐Verschiebung

Large Stokes Shift Ionic‐Liquid Dye

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Unter dem Ab‐initio‐Mikroskop: molekulare Beiträge in der Femtosekunden‐Stokes‐Verschiebung eines Reichardt‐Farbstoffs

Cited by 4 publications

References 40 publications

Ab Initio H2O in Realistic Hydrophilic Confinement

Ab Initio H2O in Realistic Hydrophilic Confinement

Ionische Flüssigkeit mit eingebautem Farbstoff zeigt große Stokes‐Verschiebung

Large Stokes Shift Ionic‐Liquid Dye

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Ab Initio H₂O in Realistic Hydrophilic Confinement

Ab Initio H₂O in Realistic Hydrophilic Confinement