Photoejection of cations from complexes with a crown-ether-linked merocyanine evidenced by ultrafast spectroscopy

Martin, Monique M.; Plaza, Pascal; Hung, Nguyen Ba; Meyer, Yves; Bourson, Jean; Valeur, Bernard

doi:10.1016/0009-2614(93)90065-9

Cited by 85 publications

(77 citation statements)

References 11 publications

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“…A slight bleaching (~ < 0) can be seen around 420 urn. Within 3 ps a strong increase in the transient absorption around 530 nm is observed, confirming our pre~ious observations [7], which lead us to suggest rapid formation of the free DCM-crown by cation photoejection from the complex excited state. In the present experiment~ LkD is also found to increase in the range 380-440 nm, where free DCM-crown transient absorption is also expected.…”

Section: Resultssupporting

confidence: 73%

“…Similar conclusions have been drawn from the observation of "crowned" donoracceptor stilbene derivatives [6]. A preliminary investigation of DCM-erown and its complexes by picosecond pump-probe spectroscopy has provided evidence for a disruption of the interaction between the cation and the nitrogen atom of the crown [7]. Further study of the excited-state phenomena by this technique is reported here.…”

Section: Dcm-crownsupporting

confidence: 63%

“…Pump-probe experiments are carried out with a two-beam probe arrangement as in Ref. 7. The transient spectra are accumulated over 500 laser shots.…”

Section: Methodsmentioning

confidence: 99%

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A new concept of photogeneration of cations: Evidence for photoejection of Ca2+ and Li+ from complexes with a crown-ether-linked merocyanine by picosecond spectroscopy

et al. 1994

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Time-resolved transient absorption and gain spectra of DCM-crown and its complexes with Li(+) and Ca(2+) in acetonitrile are measured in the wavelength range 370-670 nm after subpicosecond excitation at 425 nm. The results give evidence for the fast formation of free DCM-crown from both excited complexes, with a faster rate for the Li(+) complex. A two-step mechanism is found for the initial decay (within 30 ps) of the free DCM-crown.

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Section: Resultssupporting

confidence: 73%

Section: Dcm-crownsupporting

confidence: 63%

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A new concept of photogeneration of cations: Evidence for photoejection of Ca2+ and Li+ from complexes with a crown-ether-linked merocyanine by picosecond spectroscopy

et al. 1994

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“…[25][26][27] However, complete disconjugation of the nitrogen atom and the π-electronic system, which is observed for protonation in acidic media, does not occur. The absence of such a disconjugation in our case is in line with the observation that the absorption spectra of magnium complexes Ibc are situated at longer wavelengths compared with the spectra of protonated flavonol and have a higher intensity.…”

Section: Methodsmentioning

confidence: 99%

“…Similar dissociation of the complex in the excited state is observed also for other compounds that possess an azacrown group. 25,26,28 More significant increase of Ba 2+ ion concentration in solution results in the disappearance of the bands of flavonol I and the appearance of a new band of emission with high intensity and a maximum at 535 nm. In our opinion, this emission band corresponds to an "external" complex, which does not exist in a ground state.…”

Section: Methodsmentioning

confidence: 99%

Flavonols and Crown-Flavonols as Metal Cation Chelators. The Different Nature of Ba²⁺and Mg²⁺Complexes

et al. 1998

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The derivatives of 3-hydroxyflavone exhibit excited-state intramolecular proton transfer (ESIPT) reaction with significant (60-80 nm) shifts of fluorescence spectra between normal and phototautomer forms. This fact makes these compounds attractive as fluorescence probes in analytical chemistry, biophysics, and molecular biology. Different flavonol derivatives, including 4′-(monoaza-15-crown-5)flavonol, were synthesized, and their absorption and fluorescent spectra were studied in acetonitrile in the presence of different concentrations of Mg 2+ and Ba 2+ ions. It was shown that the general feature of flavonols is the ability to form two types of complexes with alkaline-earth cations: the low-stability "external" and high-stability chelating complexes. On the formation of the complexes, parent flavonols and their 4′-dialkylamino derivatives undergo different perturbations of their electronic structures. 4′-(Monoaza-15-crown-5)flavonol forms two types of complexes with both Mg 2+ and Ba 2+ ions; the sequence of steps in formation of Ba 2+ and Mg 2+ complexes is different.

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Luminescent Spectroscopy in Supramolecular Chemistry

Erbaş-Çakmak

Guliyev

Akkaya

2012

Supramolecular Chemistry

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Luminescence phenomena are highly sensitive to microenvironment. Consequently, supramolecular processes may induce remarkable changes in the emission character of the interacting molecular species. These changes could be useful in designing functional luminophores, such as luminescent molecular sensors for ions and neutral molecules, or just for probing supramolecular interactions. In this chapter, the photophysical processes, such as internal charge transfer (ICT), excitation energy transfer, and photoinduced electron transfer (PeT), are presented, since they are modulated by supramolecular interactions.

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Photoejection of cations from complexes with a crown-ether-linked merocyanine evidenced by ultrafast spectroscopy

Cited by 85 publications

References 11 publications

A new concept of photogeneration of cations: Evidence for photoejection of Ca2+ and Li+ from complexes with a crown-ether-linked merocyanine by picosecond spectroscopy

A new concept of photogeneration of cations: Evidence for photoejection of Ca2+ and Li+ from complexes with a crown-ether-linked merocyanine by picosecond spectroscopy

Flavonols and Crown-Flavonols as Metal Cation Chelators. The Different Nature of Ba²⁺and Mg²⁺Complexes

Luminescent Spectroscopy in Supramolecular Chemistry

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Photoejection of cations from complexes with a crown-ether-linked merocyanine evidenced by ultrafast spectroscopy

Cited by 85 publications

References 11 publications

A new concept of photogeneration of cations: Evidence for photoejection of Ca2+ and Li+ from complexes with a crown-ether-linked merocyanine by picosecond spectroscopy

A new concept of photogeneration of cations: Evidence for photoejection of Ca2+ and Li+ from complexes with a crown-ether-linked merocyanine by picosecond spectroscopy

Flavonols and Crown-Flavonols as Metal Cation Chelators. The Different Nature of Ba2+and Mg2+Complexes

Luminescent Spectroscopy in Supramolecular Chemistry

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Product

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Flavonols and Crown-Flavonols as Metal Cation Chelators. The Different Nature of Ba²⁺and Mg²⁺Complexes