Organic Hourglass Inclusions: A Review of Past and Recent Work and a Student Experiment

Kahr, Bart; Chow, Jason K.; Peterson, Matthew L.

doi:10.1021/ed071p584

Cited by 26 publications

(12 citation statements)

References 6 publications

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“…The opacity developed in definite zones, particularly a distinct hourglass shape in 4, indicating a solid-state reaction via specific crystal axes. [46][47][48] It is unlikely that the opacity is caused by photochemical dimerization since both SHB/FSHB and HB crystals develop it and the powdery coating is highly photoluminescent. Moreover, we minimized exposure of these compounds to room light to prevent the dimerization.…”

Section: Discussionmentioning

confidence: 99%

Crystal Structure and Triboluminescence 2. 9-Anthracenecarboxylic Acid and Its Esters

et al. 1997

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Triboluminescence activity is usually assumed to be a consequence of crystal dissymmetry; however, the multitude of reports of centrosymmetric triboluminescent materials cast doubt on that assumption. We examine here the connection between triboluminescence and crystal symmetry without prejudice, by synthesizing 12 esters of 9-anthracenecarboxylic acid and correlating their triboluminescence activity and that of the acid with crystal structure, purity, and photoluminescence. In this series, a noncentrosymmetric crystal structure is necessary but not sufficient for triboluminescence in relatively pure materials; impurities are necessary for triboluminescence activity in all centrosymmetric and one noncentrosymmetric materials. Crystallization motif and other structure factors were only weakly correlated with triboluminescence. The results provide evidence in support of a charge separation and recombination mechanism for the excitation of the triboluminescence.Supporting Information Available: For 3-4 and 6-12, complete lists of atomic coordinates, bond lengths, bond angles, and anisotropic displacement coefficients (52 pages); for 2-4 and 6-12, correlation of crystal cell parameters with stacking motif (1 page); and observed and calculated structure factors (46 pages). Ordering information is given on the current masthead page. CM960438R

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Section: Discussionmentioning

confidence: 99%

Crystal Structure and Triboluminescence 2. 9-Anthracenecarboxylic Acid and Its Esters

et al. 1997

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“…31,32,33,34 SSY in micromolar concentrations had earlier been studied in crystals of K 2 SO 4,35,36 and by our group 37,38 and others in KH 2 PO 4 .39,40,41 These mixed crystals grow at solution concentrations of SSY known to favor the formation of dimers and trimers, on their way to chromonic aggregates. 31,32,33,34 SSY in micromolar concentrations had earlier been studied in crystals of K 2 SO 4,35,36 and by our group 37,38 and others in KH 2 PO 4 .39,40,41 These mixed crystals grow at solution concentrations of SSY known to favor the formation of dimers and trimers, on their way to chromonic aggregates.…”

Section: Introductionmentioning

confidence: 93%

Structural Correspondence of Solution, Liquid Crystal, and Crystalline Phases of the Chromonic Mesogen Sunset Yellow

Xiao

Carter

et al. 2014

Crystal Growth & Design

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The azo dye, sunset yellow, is a prototypical, chromonic liquid crystal in which assembly in aqueous solution at high volume fraction leads to lyotropic mesophases with a "package of properties distinct in almost every aspect" (Lydon, J. Curr. Opin. Colloid Interfac. Sci. 2004, 8, 480). In particular, the isotropic to nematic transition in such phases, the consequence of stacking of dye molecules in chains, is difficult to bring into correspondence with athermal theories for rigid rods as well as modifications that consider chain interactions with one another. Chromonic mesogens, small molecules that stack to form lyotropic liquid crystals, prompt structural questions that have yet to be answered; a full understanding of structure should inform colligative properties. Herein, the single crystal structure of a guanidinium salt of the sunset yellow dianion, a known chromonic mesogen, is reported. The compound crystallizes as a dihydrate, tetrahydrofuran solvate in the orthorhombic space group Pnna, with a = 6.8426 (5) Å, b = 20.048(1) Å, c = 21.466(2) Å. The sunset yellow molecules, point group approximately C s , are disordered about a crystallographic diad axis. The structure is informative because pairwise interactions in the disordered crystal structure show a remarkable correspondence with the stereochemistry of sunset yellow molecules in solution and in the liquid crystal phase. The solution structure is here simulated by the combination of molecular dynamics, metadynamics, and quantum chemical computations. The comparable disorder in the fluid and solid states suggests the possibility that stacked aggregates adhere to growing crystals intact. Computations evaluated proposals that stacking faults and branching pointslower the X-ray correlation lengths while preserving extended structures. Evidence is found for stacking faults but not branches. The solution stereochemistry and stereodynamics has implications for the geometry of long rods, for which understanding is a prerequisite for reckoning properties of vexing chromonic mesophases.

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“…Serra et al (1998aSerra et al ( , 1998b trapped luminescent europium(III) and terbium(III) βdiketonates in K 2 SO 4 crystals, and obtained in such a way luminescent hourglass inclusions. This work was inspired by the well-known hourglass crystals consisting of organic dyes trapped into K 2 SO 4 crystals (Kahr et al, 1994(Kahr et al, , 1996.…”

Section: Photoluminescencementioning

confidence: 99%

Rare-earth beta-diketonates

Binnemans

2005

Handbook on the Physics and Chemistry of Rare Earths

403

303

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Contents 157 5.6. Solution structure 157 5.7. Electrochemical properties 158 5.8. Thermodynamic properties 159 5.9. Magnetic properties 159 5.10. Crystal-field splittings 160 5.11. Infrared spectra 161 5.12. Chirality sensing 161 5.13. Properties of hemicyanine dyes with βdiketonate counter ions 162 6. Luminescence of β-diketonate complexes 162 6.1. Photoluminescence 162 6.2. Electroluminescence 178 6.3. Triboluminescence 179 6.4. Sensitized chemiluminescence 183 7. From complexes to materials 185 7.1. Sol-gel glasses 185 7.2. Ormosils 186 7.3. β-Diketonates in polymer matrices 190 7.4. β-Diketonates in zeolites 195 7.5. Langmuir-Blodgett films (LB films) 197 7.6. Liquid crystals 200 7.7. Nonlinear optical materials 203 8. From materials to devices 205 8.1. Chelates for lasers 205 8.2. Organic light-emitting diodes (OLEDs) 206 8.3. Liquid crystal displays (LCDs) 216 8.4. Polymeric optical waveguides and amplifiers 217 9. NMR shift reagents 218 9.1. Historical development and general principles 218 9.2. Achiral shift reagents 221 9.3. Chiral shift reagents 226 10. Analytical applications 227 10.1. Trace analysis of lanthanide ions 227 10.2. Trace analysis of organic and biomolecular compounds 229 10.3. Luminescent visualization of latent fingerprints 230 10.4. Chemical sensors 232 10.5. Stationary phases in gas chromatography 232 11. Applications of volatile complexes 233 11.1. Volatile β-diketonate complexes 233 11.2. Gas chromatographic separation of the rare earths 237 11.3. Preparation of thin films by metalorganic chemical vapor deposition (MOCVD) 238 11.4. Preparation of thin films by atomic layer deposition (ALD) 241 11.5. Fuel additives 242 12. Solvent extraction 243 13. Catalytic properties 247

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Organic Hourglass Inclusions: A Review of Past and Recent Work and a Student Experiment

Abstract: Discussion of the history and utility of organic hourglass inclusions and a recipe for synthesizing a particular system (K2SO4 containing acid fuchsin), the quantification of the dye content, and the observation of its dichroism.

Cited by 26 publications

References 6 publications

Crystal Structure and Triboluminescence 2. 9-Anthracenecarboxylic Acid and Its Esters

Crystal Structure and Triboluminescence 2. 9-Anthracenecarboxylic Acid and Its Esters

Structural Correspondence of Solution, Liquid Crystal, and Crystalline Phases of the Chromonic Mesogen Sunset Yellow

Rare-earth beta-diketonates

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