Characterization of New Excimer Pumped UV Laser Dyes 2. <i>p</i>‐Quaterphenyls

Fleitz, Paul A.; Seliskar, Carl J.; Steppel, R. N.; Kauffman, Joel M.; Kelly, C. J.; Ghiorghis, Alem

doi:10.1155/lc.11.99

Cited by 10 publications

(10 citation statements)

References 3 publications

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“…Linear and recently reported cyclic oligo- p -phenyls with and without methyl and t -butyl substituents are among the simplest extended π -electron systems ( Chart 4 ). Linear oligo- p -phenyls have been utilized as luminophores in dye lasers and scintillators in near-UV and visible region for many years [ 76 , 77 , 78 ] due to their photochemically and thermally robust features. Although unsubstituted oligo- p -phenyls longer than five or six repeating units have limited solubility, p -dioxane is commonly used as a solvent for reasons not fully understood by the authors.…”

Section: Resultsmentioning

confidence: 99%

Questions of Mirror Symmetry at the Photoexcited and Ground States of Non-Rigid Luminophores Raised by Circularly Polarized Luminescence and Circular Dichroism Spectroscopy: Part 1. Oligofluorenes, Oligophenylenes, Binaphthyls and Fused Aromatics

et al. 2018

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We report experimental tests of whether non-rigid, π-conjugated luminophores in the photoexcited (S1) and ground (S0) states dissolved in achiral liquids are mirror symmetrical by means of circularly polarized luminescence (CPL) and circular dichroism (CD) spectroscopy. Herein, we chose ten oligofluorenes, eleven linear/cyclic oligo-p-arylenes, three binaphthyls and five fused aromatics, substituted with alkyl, alkoxy, phenyl and phenylethynyl groups and also with no substituents. Without exception, all these non-rigid luminophores showed negative-sign CPL signals in the UV-visible region, suggesting temporal generation of energetically non-equivalent non-mirror image structures as far-from equilibrium open-flow systems at the S1 state. For comparison, unsubstituted naphthalene, anthracene, tetracene and pyrene, which are achiral, rigid, planar luminophores, did not obviously show CPL/CD signals. However, camphor, which is a rigid chiral luminophore, showed mirror-image CPL/CD signals. The dissymmetry ratio of CPL (glum) for the oligofluorenes increased discontinuously, ranging from ≈ −(0.2 to 2.0) × 10−3, when the viscosity of the liquids increased. When the fluorene ring number increased, the glum value extrapolated at [η] = 0 reached −0.8 × 10−3 at 420 nm, leading to (–)-CPL signals predicted in the vacuum state. Our comprehensive CPL and CD study should provide a possible answer to the molecular parity violation hypothesis arising due to the weak neutral current mediated by the Z0-boson.

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Section: Resultsmentioning

confidence: 99%

Questions of Mirror Symmetry at the Photoexcited and Ground States of Non-Rigid Luminophores Raised by Circularly Polarized Luminescence and Circular Dichroism Spectroscopy: Part 1. Oligofluorenes, Oligophenylenes, Binaphthyls and Fused Aromatics

et al. 2018

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“…The empirical model proposed here was compared to previous models. Using a combination of data sets from various authors, − the parameter, θ, that Seliskar and co-workers proposed in their work, and the model proposed here, Figures and show that the new model markedly outperforms that of Seliskar et al on the prediction of both maximum molar absorption values and lasing maxima from XeCl pumping; the R 2 coefficients of determination for laser maxima and maximum molar absorption are 0.8200 and 0.9081, respectively, for the Seliskar et al method and 0.9778 and 0.9319 for the new model. This demonstrates that η is clearly the better parameter for predicting the properties of p -phenylene compounds, compared with the previous models, on account of its clear improvements in predictive quality and its more physical interpretation.…”

Section: Results and Discussionmentioning

confidence: 75%

“…Links between the structure of poly- p -phenylenes and their optical properties have been the subject of previous reports, focusing on the effect of three structural variables: the number of p -phenylene subunits, chemical substitution of these subunits, − and the bridging of the 2 and 2′ positions which constrains the torsion angles between the rings (Scheme ). , …”

Section: Introductionmentioning

confidence: 99%

Systematic Molecular Design of p-Phenylene Lasing Properties

2013

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In an effort to design p-phenylene laser dyes with molecular properties which allow them to work more effectively with 308 nm XeCl lasers, two new empirical theories are proposed to predict the peak lasing wavelength of terminally substituted p-phenylene laser dyes. These theories account for variable numbers of p-phenylene units, different terminal groups with a range of electronic properties, and the effects of bridging between p-phenylene units. Both empirical models predict maximum molar absorption coefficients in addition to peak lasing wavelengths with the one intuitive parameter. Possibilities for the molecular engineering of p-phenylene properties are achieved with these new models, which have also been used to forecast the properties of two further p-phenylene compounds.

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“…This effect was in the same direction as we observed in the p-quaterphenyls. 3 The FWHM (or the corresponding tuning ranges) of the tuning curves for these p-quinquiphenyls are typical of the p-oligophenylenes in this wavelength region, about 10 nm.…”

Section: Quinquiphenylsmentioning

confidence: 96%

Characterization of New Excimer Pumped UV Laser Dyes 3.P‐Quinqui‐, Sexi‐, Octi‐ and Deciphenyls

Seliskar¹,

Landis²,

Kauffman³

et al. 1992

Laser Chemistry

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The spectroscopic and lasing characteristics of a series of 308 nm pumped p-oligophenylenes with five or more phenyl rings have been studied. Quantitative comparisons of the absorption spectra of these dyes with numerous other dyes in this class of compounds can be made by defining a parameter, theta, as the sum of the number of phenyl rings and the number of ring-bridges. Statistically good linear regressions result from the correlations of molar extinction with theta and from wavelength of absorbance with the reciprocal of theta. We find that these correlations provide good predictive information in deciding which dyes to attempt to synthesize for testing. The lasing characteristics of the dyes studied show that these dyes are amongst the best dyes in this class of dyes. Some of these dyes have exceptionally long lifetimes coupled with acceptable conversion efficiencies.

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Characterization of New Excimer Pumped UV Laser Dyes 2. p‐Quaterphenyls

Cited by 10 publications

References 3 publications

Questions of Mirror Symmetry at the Photoexcited and Ground States of Non-Rigid Luminophores Raised by Circularly Polarized Luminescence and Circular Dichroism Spectroscopy: Part 1. Oligofluorenes, Oligophenylenes, Binaphthyls and Fused Aromatics

Questions of Mirror Symmetry at the Photoexcited and Ground States of Non-Rigid Luminophores Raised by Circularly Polarized Luminescence and Circular Dichroism Spectroscopy: Part 1. Oligofluorenes, Oligophenylenes, Binaphthyls and Fused Aromatics

Systematic Molecular Design of p-Phenylene Lasing Properties

Characterization of New Excimer Pumped UV Laser Dyes 3.P‐Quinqui‐, Sexi‐, Octi‐ and Deciphenyls

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