Fluorescence of 9-anthroic acid and its esters. Environmental effects on excited-state behavior

Werner, Tobias; Hercules, David M.

doi:10.1021/j100726a060

Cited by 121 publications

(83 citation statements)

References 2 publications

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“…The nearest Eu···Eu distance along the length of an ADC unit is 11.4 Å. Interestingly, the carboxylate groups are significantly twisted outside the plane of the anthracene moiety and measure 63.6 • (C6-C2-C1-O2) for the bis-chelating, 85.8 • (C11-C10-C9-O3) for the bis-bridging, and 68.7 • for the bis-bridging/chelating ligands. The twisting of the carboxylate groups, as compared to a coplanar configuration, is consistent with reported DFT calculations on the parent H 2 ADC molecule, which showed its potential energy to be at a minimum with a 60 • rotation of the COOH group [35]. The interconnectivity of the chains through the Eu1 atoms creates a 3-D arrangement, with channels along the b axis and the coordinated DMF solvent inside.…”

Section: Structure Descriptionsupporting

confidence: 87%

Anthracene-Based Lanthanide Metal-Organic Frameworks: Synthesis, Structure, Photoluminescence, and Radioluminescence Properties

et al. 2018

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Four anthracene-based lanthanide metal-organic framework structures (MOFs) were synthesized from the combination of the lanthanide ions, Eu 3+ , Tb 3+ , Er 3+ , and Tm 3+ , with 9,10-anthracenedicarboxylic acid (H 2 ADC) in dimethylformamide (DMF) under hydrothermal conditions. The 3-D networks crystalize in the triclinic system with P-1 space group with the following compositions: (i) {{[Ln 2 (ADC) 3 (DMF) 4 ·DMF]} n , Ln = Eu (1) and Tb (2)} and (ii) {{[Ln 2 (ADC) 3 (DMF) 2 (OH 2 ) 2 ·2DMF·H 2 O]} n , Ln = Er (3) and Tm (4)}. The metal centers exist in various coordination environments; nine coordinate in (i), while seven and eight coordinate in (ii). The deprotonated ligand, ADC, assumes multiple coordination modes, with its carboxylate functional groups severely twisted away from the plane of the anthracene moiety. The structures show ligand-based photoluminescence, which appears to be significantly quenched when compared with that of the parent H 2 ADC solid powder. Structure 2 is the least quenched and showed an average photoluminescence lifetime from bi-exponential decay of 0.3 ns. On exposure to ionizing radiation, the structures show radioluminescence spectral features that are consistent with the isolation of the ligand units in its 3-D network. The spectral features vary among the 3-D networks and appear to suggest that the latter undergo significant changes in their molecular and/or electronic structure in the presence of the ionizing radiation.

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Section: Structure Descriptionsupporting

confidence: 87%

Anthracene-Based Lanthanide Metal-Organic Frameworks: Synthesis, Structure, Photoluminescence, and Radioluminescence Properties

et al. 2018

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“…This is supported by the Stokes shift observed in cyclohexane for 2-FAm. This behaviour is similar to that observed for 2-FA (27), but quite different from that of many other carboxylic acids, where the -COOH group is not coplanar in the So state but attains coplanarity with the parent aromatic molecule on excitation (37)(38)(39).…”

Section: Effect Of Solventssupporting

confidence: 73%

Prototropic reactions for 1-, 2-, and 4-fluorenamides in the ground and excited singlet states

Manoharan¹,

Dogra²

1988

Can. J. Chem.

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RAMASAMY MANOHARAN and SNEH K. DOGRA. Can. J. Chem. 66, 2375Chem. 66, (1988. Absorption and fluorescence spectra of 1-, 2-and 4-fluorenamides (1-FAm, 2-FAm, 4-FAm) were studied in different solvents and at various acid concentrations. This study indicates that the long wavelength absorption band is long-axis polarised in 2-FAm whereas in 1-FAm and 4-FAm, it is composed of long-and short-axis polarised transitions. The -CONH2 group in 1-FAm and 4-FAm is coplanar with the fluorene moiety, whereas the same group in 2-FAm is non-coplanar with the fluorene ring in non-polar solvents, both in So and S, states, but attains coplanarity in the polar and hydrogen bonding solvents in the SI state. Hammett's acidity scale is not valid for the protonation reaction of amides and a medium effect is observed on the absorption spectra of the monocations in strong sulphuric acid. The prototropic equilibrium for the protonation of ring carbon atom is not established in the S1 state, due to the slower rate of protonation reaction. Proton-induced fluorescence quenching of the monocations is followed before the monocations are being protonated.RAMASAMY MANOHARAN et SNEH K. DOGRA. Can. J. Chem. 66,2375Chem. 66, (1988. Utilisant diffkrents solvents et des concentrations diffkrentes d'acide, on a Ctudit les spectres de fluorescence des fluorhamides-1, -2 et -4 (FAm-1, FAm-2, FAm-4). Ces Ctudes indiquent que la grande longueur d'onde d'absorption est polariste selon le grand axe dans le composC FAm-2 tandis que dans les composCs FAm-I et FAm-2 cette longueur d'onde est composCe de transitions polarisCes selon les deux axes. Le groupe -CONH2 du compC FAm-I et I'unitt fluorkne sont coplanaires, tandis que dans le composC FAm-2, cette coplanCaritC n'existe pas dans les solvants non-polaires dans les ttats So et S I , mais on l'observe dans 1'Ctat SI dans les solvants polaires et dans les solvants contenant des liaisons hydrogknes. L'Cchelle d'aciditk de Hammett n'est pas valable pour la reaction de protonation des amides et on observe un effet du milieu sur les spectres d'absorption des monocations dans l'acide sulfurique fort. On n'a pas pu dCterminer 1'Cquilibre prototropique de la protonation I de l'atome de carbone du cycle dans 1'Ctat S I , cause de la vitesse plus lente de la rCaction de protonation. On observe l'arrkt I de fluorescence du monocation, induit par le proton, avant la protonation des monocations.

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“…We presently have no explanation for this effect.) By (25) this distinction in y values means that wos/wf, is appreciably larger for the pair structures than for the infinite-stack ones. This difference apparently does not arise primarily from a difference in excimer frequencies in the two types of structures: this can be seen from Fig.…”

Section: Interpretation Of Resultsmentioning

confidence: 99%

The fluorescence properties of crystalline anthracenes and their dependence on the crystal structures

Cohen

Ludmer

Yakhot

1975

Physica Status Solidi (b)

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The fluorescence properties of a number of crystalline anthracenes are described. It is found that in excimer-emitting crystals the energy of the emission is shifted by change in temperature much more strongly in infinite-stack structures than in structures based on pair-wise packing. A theoretical treatment is given of the general problem of the excimer emission from a crystal, and is applied to the anthracenes. This theory shows that the sensitivity to temperature for high temperatures is determined by the ratio of the frequencies of intra-pair vibrations in ground and excited states of the particular material. An interpretation of the difference in this ratio for stack and pair structures is given, and some predictions based on this interpretation are given and tested. It is confirmed that structures in which molecular overlap is small give rise to monomer emission.Es werden die Fluoreszenzeigenschaften einer Anzahl Anthrazenkristalle beschrieben. E s wurde gefunden, da13 in ,,excimer"-emittierenden Kristallen die Emissionsenergie durch Temperaturveranderung in unendlich gestapelten Strukturen vie1 starker verschoben ist als in Strukturen, die auf der paarweisen Stapelung beruhen. Es wird eine theoretische Behandlung des allgemeinen Problems der Excimer-Emission von einem Kristall angegeben und auf Anthrazen angewendet. Diese Theorie zeigt, da13 die Temperaturempfindlichkeit fur hohe Temperaturen durch das Verhaltnis der Intra-Pam-Schwingungen im Grundzustand und den angeregten Zustanden des betreffenden Materials bestimmt wird. Es wird eine Interpretation des Unterschieds in diesem Verhaltnis fur Stapel-und Paar-Strakturen gegeben und es nerden einige Vorhersagen auf der Grundlage dieser Interpretation gemacht und gepruft. Es wird bestatigt, da13 Strukturen, in denen die Molekuluberlappung klein ist, RnlaB zu monomerer Emission geben.

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Fluorescence of 9-anthroic acid and its esters. Environmental effects on excited-state behavior

Cited by 121 publications

References 2 publications

Anthracene-Based Lanthanide Metal-Organic Frameworks: Synthesis, Structure, Photoluminescence, and Radioluminescence Properties

Anthracene-Based Lanthanide Metal-Organic Frameworks: Synthesis, Structure, Photoluminescence, and Radioluminescence Properties

Prototropic reactions for 1-, 2-, and 4-fluorenamides in the ground and excited singlet states

The fluorescence properties of crystalline anthracenes and their dependence on the crystal structures

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