Excited-state double proton transfer in the solid state: the dimers of 1-azacarbazole

Waluk, Jacek; Herbich, Jerzy; Oelkrug, D.; Uhl, S.

doi:10.1021/j100408a002

Cited by 42 publications

(26 citation statements)

References 4 publications

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“…Although the strong experimental bands at 770 cm −1 and 741 cm −1 have been correlated with those of highest intensities, 39 and 42 , respectively, it is apparent in Fig. 4 that they also cover the weak 40 and 41 bands calculated at 755 cm −1 and 746 cm −1 .…”

Section: Spectral Region 1000-700 CM −1mentioning

confidence: 87%

See 1 more Smart Citation

Combined study of vibrational spectra of α-carboline by theoretical and experimental IR methods

Muñoz

Sánchez‐Coronilla

Carmona

et al. 2011

Vibrational Spectroscopy

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Section: Spectral Region 1000-700 CM −1mentioning

confidence: 87%

“…While much work has been done on the photophysics of the cyclic complexes of ␣CB [35][36][37][38][39], the possible ground state selfassociated structures in solution are still under study by UV-vis spectroscopy techniques [40].…”

Section: Discussionmentioning

confidence: 99%

Combined study of vibrational spectra of α-carboline by theoretical and experimental IR methods

Muñoz

Sánchez‐Coronilla

Carmona

et al. 2011

Vibrational Spectroscopy

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“…The results of the drastic deuterium isotope effect for the tautomer emission intensity indicate tunnelling as the principal mechanism for ESDPT at low temperature. In yet another approach, in a carefully prepared non-polar polymer matrix, the oligomer formation in 7AI may be dynamically prohibited at cryogenic temperature, as the rigid environment prevents diffusive motion of the pre-existing 7AI dimer at ambient temperature [49]. Nevertheless, such careful preparations, in our experience, still involve several sensitive parameters, such as concentration, which causes a possible microcrystalline formation owing to low solubility, temperature gradient and protic solvent contamination, resulting in intrinsic difficulty in achieving an ideal 7AI dimeric formation.…”

Section: Esdpt Dynamics Of 7ai Analogue Homodimers In the Solid Statementioning

confidence: 99%

Excited‐State Proton Transfer via Hydrogen‐Bonded Dimers and Complexes in Condensed Phase

Hsieh

Jiang

Chou

2010

Hydrogen Bonding and Transfer in the Excited State

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Proton transfer represents one of the most fundamental processes involved in chemical reactions as well as in living systems [1]. Vast numbers of scientists have been participating in relevant research, leading to thousands upon thousands of publications and numerous books on the topic. Accordingly, various types of proton transfer reaction, depending on, for example, the reaction in the ground or excited state, adiabatic versus non-adiabatic, strong and weak hydrogen bonding, acidity (proton donor) and basicity (proton acceptor), have been identified [2][3][4][5][6][7][8]. At this time, proton transfer reactions seem to have the potential for unlimited extensions and aspects in terms of fundamentals and applications. Thus, to cover the broad spectrum of proton transfer research within a limited number of pages seems to be an unachievable task. Rather than trying to achieve the impossible, this chapter focuses mainly on areas related to excited-state proton transfer (ESPT) [9] with pre-existing intramolecular hydrogen bonds. Under this constraint, the photoinduced process involving excited-state proton dissociation and/or protonation in bulk solvents or clusters, also a currently active topic that has received considerable attention [10][11][12][13][14], unfortunately cannot be addressed in this chapter.One particular focus of this chapter is bifunctional molecules possessing a proton donor group and a proton acceptor group, such that ESPT takes place via self-associated hydrogen-bonded (HB) dimers and/or solvent bridge relay. In spite of numerous explorations and elegant research on guest-molecule-assisted ESPT reactions, the results of which have provided great insight into the fundamentals as well as perspectives in applications,

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“…As the temperature for the vanishing of this emission crucially depended on the solvent viscosity, these authors concluded that, unlike the AI dimer, the phototautomerization of the AC dimer was viscosity controlled (4). Conversely, in the crystal phase, where the AC molecules formed doubly hydrogen bonded centro‐symmetric dimers (18), the ESDPT process occurred without apparent energy barrier and the fluorescence of the tautomer was detected throughout the temperature range studied (from 293 K to 1.5 K) (5). It is noteworthy that in the solid phase, the structure of the AI crystals consisted of basket‐like tetramers, in which each AI molecule was doubly hydrogen bonded to two other AI partners (19,20).…”

Section: Introductionmentioning

confidence: 99%

A Photophysical Study of the α‐Carboline (1‐Azacarbazole) Aggregation Process

García‐Fernández

Carmona

Muñoz

et al. 2012

Photochem & Photobiology

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This paper reports a comprehensive photophysical study of the aggregation process of 1-azacarbazole, or α-carboline (9H-pyrido[2,3-b]indole), AC, in low polar aprotic solvents by using absorption, steady state and time-resolved fluorescence spectroscopic techniques. To ascertain the characteristics of the aggregation process we have studied the changes produced by the increase of the AC concentration and the decrease of the temperature on the absorption and fluorescence spectra of the AC monomer. Previously, to aid the interpretation of these results, the hydrogen bonding interactions of the AC monomer with pyridine, PY, and indole, IND, have been also analyzed. The results obtained from these studies reveal that, under our experimental conditions, AC does not form doubly hydrogen bonded cyclic dimers, (AC)(2), but singly hydrogen bonded open dimers, AC-AC, and open higher aggregates, (-AC-)(n). The formation of these species shifts to the red the absorption spectrum of the AC monomer and quenches its fluorescence.

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Excited-state double proton transfer in the solid state: the dimers of 1-azacarbazole

Cited by 42 publications

References 4 publications

Combined study of vibrational spectra of α-carboline by theoretical and experimental IR methods

Combined study of vibrational spectra of α-carboline by theoretical and experimental IR methods

Excited‐State Proton Transfer via Hydrogen‐Bonded Dimers and Complexes in Condensed Phase

A Photophysical Study of the α‐Carboline (1‐Azacarbazole) Aggregation Process

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