Excited-State Proton Transfer of 2-Naphthol Inclusion Complexes with Cyclodextrins

Park, Hyoung‐Ryun; Mayer, Bernd; Wolschann, Peter; Koehler, G.

doi:10.1021/j100075a019

Cited by 102 publications

(70 citation statements)

References 12 publications

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“…The authors observed that ESPT of β-naphthol is effectively suppressed when 2:1 host−guest complexes are formed with α-cyclodextrin but only partially in the case of 1:1 complexes with α-and β-cyclodextrin. 28 ■ CONCLUSIONS Steady-state fluorescence emission titration curves while not giving mechanistic details of the ESPT processes are still a very useful tool to account for this phenomenon. Crucial information can be achieved upon interpretation of the data through a mathematical model recast from the Weller theory.…”

Section: ■ Results and Discussionmentioning

confidence: 99%

Excited-State Proton Transfer in Confined Medium. 4-Methyl-7-hydroxyflavylium and β-Naphthol Incorporated in Cucurbit[7]uril

2014

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Excited-state proton transfer (ESPT) was studied by fluorescent emission using a mathematical model recast from the Weller theory. The titration curves can be fitted with three parameters: pK(a) (acidity constant of the ground sate), pK(ap)* (apparent acidity constant of the excited state), and η(A*), the efficiency of excited base formation from the excited acid. β-Naphthol and 4-metyhl-7-hydroxyflavylium were studied in aqueous solution and upon incorporation in cucurbit[7]uril. For all the compounds studied the interaction with the host leads to 1:1 adducts and the ground-state pK(a) increases upon incorporation. Whereas the ESPT of 4-methyl-7-hydroxyflavylium practically does not change in the presence of the host, in the case of β-naphthol it is prevented and the fluorescence emission titration curves are coincident with those taken by absorption. The position of the guest inside the host was investigated by NMR experiments and seems to determine the efficiency of the ESPT. The ESPT decreases for the guest, exhibiting a great protection of the phenol to the bulk water interaction.

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Section: ■ Results and Discussionmentioning

confidence: 99%

Excited-State Proton Transfer in Confined Medium. 4-Methyl-7-hydroxyflavylium and β-Naphthol Incorporated in Cucurbit[7]uril

2014

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“…When the solution is at lower pH, 2-naphthol and phenol can be protonized, so electrostatic repulsion existed between BHPD-Mt and protonated 2-naphthol and phenol, and the adsorption amount of them are both relatively lower. 2-Naphthol is weak acid with dissociation constant (pK a ) of 9.5 [56], as the solution pH is 10, the increased negative charge on the surface and the anionic species of 2-naphthol cause repulsive interaction electrostatically. Hence, the adsorption amount of 2-naphthol is decreased significantly, which was also reported by Tai [48].…”

Section: Effect Of Phmentioning

confidence: 99%

The characterization of organo-montmorillonite modified with a novel aromatic-containing gemini surfactant and its comparative adsorption for 2-naphthol and phenol

Yang

Gao

Luo

et al. 2015

Chemical Engineering Journal

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“…While solvation dynamics of water molecules occurs in subpicosecond time scale in ordinary water, 5a it is retarded by at least 3 orders of magnitude to the nanosecond time scale inside the cyclodextrin cavities, 5a,b micelles, 6 and microemulsions. 7 The intermolecular proton transfer processes are also found to be markedly affected by cyclodextrins, [8][9][10][11] lipids, 12 and microemulsions. 13 The excited-state double proton-transfer process 15 is also largely modified in microemulsions.…”

Section: Introductionmentioning

confidence: 99%

Excited-State Proton Transfer of 1-Naphthol in Micelles

1998

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The fast deprotonation of 1-naphthol, which occurs in 35 ps in aqueous solution, is studied in neutral (triton X 100, reduced, TX-100R), cationic (cetyl trimethylammonium bromide, CTAB), and anionic (sodium dodecyl sulfate, SDS) micelles. Drastically different effects on the proton transfer process and the relative emission intensities of the neutral form (360 nm) and the anion (460 nm) are observed in the three micelles. The intensities of the anion and the neutral emission of 1-naphthol exhibit a break around the reported critical micellar concentration (cmc) of the three micelles. Above cmc, intensity of the neutral emission is enhanced by a factor of nearly 90, 66, and 20 in 20 mM TX-100R, 200 mM SDS, and 96 mM CTAB, respectively. The anion emission is enhanced for CTAB and TX-100R, while for SDS its intensity decreases, compared to water. In CTAB, the rise time of the 460 nm emission (600 ( 100 ps) is similar to the lifetime of decay at 360 nm. However, for TX-100R and SDS, the rise time of the anion emission (at 460 nm) is found to be faster than the decay of the neutral emission (at 360 nm). This indicates that in TX-100R and SDS, there is no parental relation between the normal and the anion emission and they originate from the probe, 1-naphthol molecules, at distinctly different locations. The rise times at 460 nm are 1.8 ( 0.1 ns and 600 ( 100 ps for TX-100R and SDS, respectively, while the corresponding decay times at 360 nm are 2.5 ( 0.1 ns and 1.8 ( 0.1 ns.

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Excited-State Proton Transfer of 2-Naphthol Inclusion Complexes with Cyclodextrins

Cited by 102 publications

References 12 publications

Excited-State Proton Transfer in Confined Medium. 4-Methyl-7-hydroxyflavylium and β-Naphthol Incorporated in Cucurbit[7]uril

Excited-State Proton Transfer in Confined Medium. 4-Methyl-7-hydroxyflavylium and β-Naphthol Incorporated in Cucurbit[7]uril

The characterization of organo-montmorillonite modified with a novel aromatic-containing gemini surfactant and its comparative adsorption for 2-naphthol and phenol

Excited-State Proton Transfer of 1-Naphthol in Micelles

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