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

Martin, Monique M.; Plaza, Pascal; Meyer, Yves; Bégin, L.; Bourson, Jean; Valeur, Bernard

doi:10.1007/bf01881437

Cited by 18 publications

(7 citation statements)

References 8 publications

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“…It is interesting that the cation which was initially attracted to the receptor is no longer welcome due to the new photogenerated repulsion. These principles were first crystallized to rationalize the increased acidity of phenols in the excited state , and later exploited in the pH jump method for photogenerating proton (or hydroxide) pulses. 175a,, However the generality of these principles and their application to metal ion-sensing phenomena was not realized until Valeur − and Lapouyade and Rettig 181-184a had conducted extensive steady state and kinetic studies on 18 and 19 , respectively. Alfimov's systems also display photocontrolled cation binding, although most of them are weakly fluorescent (see 37 233 for an example).…”

Section: Charge-transfer (Ct) Excited States and Relativesmentioning

confidence: 99%

“…[210][211][212][213][214] A related study is available for 2,2′bipyridyl-3,3′-diol when it binds Zn(II). 215 For instance, the weakened cation binding in the excited state (which leads to cation disengagement) [178][179][180][181][182][183][184] can be quantitated in this way. [211][212][213] Prior to this benevolent invasion of biology by molecular fluorescent sensors/switches, there were examples quietly serving analytical chemistry.…”

Section: Signaling Recognition Eventsmentioning

confidence: 99%

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Signaling Recognition Events with Fluorescent Sensors and Switches

et al. 1997

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Section: Charge-transfer (Ct) Excited States and Relativesmentioning

confidence: 99%

Section: Signaling Recognition Eventsmentioning

confidence: 99%

Signaling Recognition Events with Fluorescent Sensors and Switches

et al. 1997

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“…Irreversible photoinduced changes in the chemical structure of a calcium chelator (EGTA type) with the effect of supressing the coordinating role of a nitrogen atom was shown to result in a decrease of the stability constant of the complex by a factor of 10−30 . In previous papers, , we provided evidence for cation photorelease from Li + − and Ca 2+ −DCM−crown complexes by picosecond pump−probe spectroscopy and suggested that photoejection occurs from the excited complex, once the latter has relaxed to its charge−transfer state reported a picosecond study of a crown−phenylstilbene derivative complexed with Ca 2+ and proposed an excited-state mechanism including a reversible breaking of the nitrogen−calcium interaction followed by the reversible formation of a solvent-separated cation−probe pair.…”

Section: Introductionmentioning

confidence: 92%

Steady-State and Picosecond Spectroscopy of Li⁺ or Ca²⁺ Complexes with a Crowned Merocyanine. Reversible Photorelease of Cations

Martin¹,

Plaza²,

Meyer³

et al. 1996

J. Phys. Chem.

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Reversible photorelease of Li+ and Ca2+ cations from complexes with a crowned derivative of the merocyanine dye DCM (4-(dicyanomethylene)-2-methyl-6-(p-(dimethylamino)styryl)-4H-pyran) in acetonitrile is investigated by steady-state and time-resolved spectroscopy. The results obtained by fluorescence spectroscopy reveal the presence of two emitting species in solutions containing DCM−crown complexes. One species with a 2 ns lifetime is attributed to the free ligand resulting from cation photorelease, with a maximum formation yield of 86% for Li+ and 41% for Ca2+. The other one with a 400 ps slightly blue-shifted emission for both cations is suggested to be due to a loose complex. The mechanism of cation photorelease is studied by transient absorption and gain spectroscopy within 2 ns after excitation with a 0.7 ps pulse at 425 nm. In the 360−660 nm spectral range, the main changes observed take place within 30 ps. For longer time delays the time-resolved differential spectra indicate a dominant decay of 1.5−2 ns in all spectral regions. From the analysis of the early spectral changes, it is concluded that the dominant excited-state mechanism includes the disruption of the binding between the nitrogen atom of the crown and the cation in the locally excited state of the complex, followed by intraligand charge transfer at a slower rate for Ca2+ than for Li+. In spite of the absence of experimental evidence for cation diffusion to the bulk, a significant increase in concentration of free cations should be obtained by using light pulses of long duration.

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“…Further, the ligand hole contribution at the wavelength of the isosbestic point, 485 nm, if any, is strongly overshadowed by the LMCT GSB and the ESA of S n (d) origin. We note that analyzing isosbestic points in transient absorption spectra at the many picoseconds timescale has precedence. − …”

Section: Results: Transient Optical Spectroscopy and Td-dft Calculationsmentioning

confidence: 99%

Long-Lived LMCT in a d⁰ Vanadium(V) Complex by Internal Conversion to a State of 3d_xy Character

et al. 2015

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Vous avez des questions? Nous pouvons vous aider. Pour communiquer directement avec un auteur, consultez la première page de la revue dans laquelle son article a été publié afin de trouver ses coordonnées. Si vous n'arrivez pas à les repérer, communiquez avec nous à PublicationsArchive-ArchivesPublications@nrc-cnrc.gc.ca. Questions? Contact the NRC Publications Archive team atPublicationsArchive-ArchivesPublications@nrc-cnrc.gc.ca. If you wish to email the authors directly, please see the first page of the publication for their contact information. NRC Publications Archive Archives des publications du CNRCThis publication could be one of several versions: author's original, accepted manuscript or the publisher's version. / La version de cette publication peut être l'une des suivantes : la version prépublication de l'auteur, la version acceptée du manuscrit ou la version de l'éditeur. NRC Publications Record / Notice d'Archives des publications de CNRC:http://nparc.cisti-icist.nrc-cnrc.gc.ca/eng/view/object/?id=5da554e5-7ac2-43d0-bfc9-07b668c650eb http://nparc.cisti-icist.nrc-cnrc.gc.ca/fra/voir/objet/?id=5da554e5-7ac2-43d0-bfc9-07b668c650eb ABSTRACT:The excited state dynamics of a d 0 vanadium(V) oxido ligand-tometal charge transfer (LMCT) complex, VOL F , were investigated via a combination of static optical and X-ray absorption (XAS) spectroscopy, transient optical absorption spectroscopy, and time-dependent density functional theory (TD-DFT). Upon excitation of the LMCT in the visible region, transient absorption data reveal that internal conversion traps the excited carrier population into a long-lived charge transfer state of 3d xy electron character, S 1 (d xy ). The internal conversion is substantiated by an isosbestic point in the transient absorption data, two nearby charge transfer states that couple well by TD-DFT, multiple rates in the ground state recovery, and the decay kinetics of an excited state absorption with the energy of a d-d transition in O K-edge XAS spectra. The long lifetime (∼420 ps) of S 1 (d xy ) can be ascribed to its poor optical and vibrational coupling to a distorted ground state (S 0 *) via a negligible electronic dipole transition in TD-DFT. The lack of luminescence or an identifiable triplet state also suggests attributing the lifetime to electronic contributions. In conjunction with its strong visible absorption and reduction potential, the long-lived LMCT suggests that molecules such as VOL F could have potential utility for energy conversion applications. Moreover, the results show that internal conversion between two nearby charge transfer states, differentiated by their 3d character, can form a long-lived charge transfer excitation, broadly informing the discovery of 3d metalcentered optical absorbers with long-lived charge transfer lifetimes.

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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

Cited by 18 publications

References 8 publications

Signaling Recognition Events with Fluorescent Sensors and Switches

Signaling Recognition Events with Fluorescent Sensors and Switches

Steady-State and Picosecond Spectroscopy of Li⁺ or Ca²⁺ Complexes with a Crowned Merocyanine. Reversible Photorelease of Cations

Long-Lived LMCT in a d⁰ Vanadium(V) Complex by Internal Conversion to a State of 3d_xy Character

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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

Cited by 18 publications

References 8 publications

Signaling Recognition Events with Fluorescent Sensors and Switches

Signaling Recognition Events with Fluorescent Sensors and Switches

Steady-State and Picosecond Spectroscopy of Li+ or Ca2+ Complexes with a Crowned Merocyanine. Reversible Photorelease of Cations

Long-Lived LMCT in a d0 Vanadium(V) Complex by Internal Conversion to a State of 3dxy Character

Contact Info

Product

Resources

About

Steady-State and Picosecond Spectroscopy of Li⁺ or Ca²⁺ Complexes with a Crowned Merocyanine. Reversible Photorelease of Cations

Long-Lived LMCT in a d⁰ Vanadium(V) Complex by Internal Conversion to a State of 3d_xy Character