Cyclic Ether Auxofluors on Oligophenylene Laser Dyes

Kauffman, Joel M.; Kelley, Charles J.; Ghiorghis, Alem; Neister, Edward; Armstrong, Lorne

doi:10.1155/lc.8.335

Cited by 12 publications

(10 citation statements)

References 19 publications

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“…This p-dianisylcarbo-benzene 1o, a tetraphenylated derivative of the central ring carbo-mer of the terphenyl fluorophore 13 (Scheme 7), 60 was obtained by the two-step procedure from the key [6]pericyclynedione 12. Oxygen-or nitrogen-functional p-disubstituted carbobenzenes.…”

Section: Hexa-hetero-substituted Carbo-benzenesmentioning

confidence: 99%

“Carbo-aromaticity” and novel carbo-aromatic compounds

et al. 2015

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While the concept of aromaticity is being more and more precisely delineated, the category of "aromatic compounds" is being more and more expanded. This is illustrated by an introductory highlight of the various types of "aromaticity" previously invoked, and by a focus on the recently proposed "aromatic character" of the "two-membered rings" of the acetylene and butatriene molecules. This serves as a general foundation for the definition of "carbo-aromaticity", the relevance of which is surveyed through recent results in the synthetic, physical, and theoretical chemistry of carbo-mers and in particular macrocyclic-polycyclic representatives constituting a natural family of "novel aromatic compounds". With respect to their parent molecules, carbo-mers are constitutionally defined as "carbon-enriched", and can also be functionally regarded as "π-electron-enriched". This is exemplified by recent experimental and theoretical results on functional, aromatic, rigid, σ,π-macrocyclic carbo-benzene archetypes of various substitution patterns, with emphasis on the quadrupolar pattern. For the purpose of comparison, several types of non-aromatic references of carbo-benzenes are then considered, i.e. freely rotating σ,π-acyclic carbo-n-butadienes and flexible σ-cyclic, π-acyclic carbo-cyclohexadienes, and to "pro-aromatic" congeners, i.e. rigid σ,π-macrocyclic carbo-quinoids. It is shown that functional carbo-mers are entering the field of "molecular materials" for properties such as linear or nonlinear optical properties (e.g. dichromism and two-photon absorption) and single molecule conductivity. Since total or partial carbo-mers of aromatic carbon-allotropes of infinite size such as graphene (graphynes and graphdiynes) and graphite ("graphitynes") have long been addressed at the theoretical or conceptual level, recent predictive advances on the electrical, optical and mechanical properties of such carbo-materials are surveyed. Very preliminary experimental results on a carbo-benzenoid fragment are finally disclosed.

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Section: Hexa-hetero-substituted Carbo-benzenesmentioning

confidence: 99%

“Carbo-aromaticity” and novel carbo-aromatic compounds

et al. 2015

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“…It is henceforth worth noting that dianisyl-carbo-benzene p-(4-MeO-C 6 H 4 ) 2 C 18 H 4 is the central ring carbo-mer of dianisyl-benzene, a stronger quadrupolar fluorophore than its terphenyl parent [49]. A rationale for the fluorescence properties of these terphenyl derivatives is based on the decrease of the local aromaticity of rings upon UV light-induced co-planarization [50].…”

Section: Synthesis Of Quadrupolar Carbo-benzenesmentioning

confidence: 99%

Variation of aromaticity by twisting or expanding the ring content

Chauvin

Lepetit

Maraval

et al. 2010

Pure and Applied Chemistry

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Generalization of the Hückel rule predicts that the (anti)aromaticity of a neutral ring is qualitatively reverted upon a single twist of the π-orbital array (Möbius interconversion), and is preserved upon expansion of all the bonds by single C 2 units (ring carbo-merization). These opposite effects are addressed from quantitative theoretical and experimental standpoints, respectively. (i) According to most resonance energy (RE) schemes, the RE value of a Möbius ring is not the opposite of that of the Hückel version. This also applies to the Aihara's and Trinajstic's topological resonance energy (TRE), where a non-aromatic reference in the topological limit is defined as being "as identical as possible" to the parent ring but just "acyclic". In spite of its conceptual merits, the computing complexity and fictitious character of the TRE acyclic reference resulted in a disuse of TRE as a current energetic aromaticity index. Both the calculation and interpretation of TRE have been revisited in light of a cross-reference between the Hückel and Möbius rings within the Hückel molecular orbital (HMO) framework. Whereas the topological influence of triple bonds is currently neglected in the first-level HMO treatment of π-conjugated systems, a graph-theoretical analysis allows one to differentiate the TRE value of a [3n]annulene from those of the corresponding carbo-[n]annulene. The C 18 ring of carbo-benzene is thus predicted to be slightly more topologically aromatic than that of [18]annulene. (ii) Recent experimental and density functional theory (DFT) theoretical studies of quadrupolar carbo-benzene derivatives are presented. The results show that the "flexible aromaticity" of the p-C 18 Ph 4 bridge between donor anisyl substituents plays a crucial role in determining the intriguing chemical/spectroscopical/optical properties of these carbo-chromophores. theme of aromaticity. ‡ Corresponding author netic,…) are not uniquely determined [4], the rule remains qualitative in nature. Before addressing the problem of its quantitative transcription, it is noted that the rule is reversed by applying elementary molecular transformations altering not only the electronic configuration (one-electron spin inversion or two-electron ionization), but also the atomic configuration: one-bond 180°-twisting or one-bond C 2 -expansion, corresponding to Möbius conversion [5] and local carbo-merization, respectively [6]. The quantitative variation of aromaticity upon both latter types of transformations is hereafter addressed from both the theoretical and experimental standpoints. TWISTING THE RING CONTENT: THE MÖBIUS KEY TO AROMATICITYAfter a critical survey of various energetic measures of aromaticity proposed in the literature [7], the relative aromaticity of Hückel and Möbius rings will be scrutinized. Their complementary roles for the quantification of topological aromaticity is then investigated not only for cyclenes, but also for conjugated alkynes and cyclynes, and in particular for ring carbo-mers. Critical survey of HMO energetic a...

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“…[12d, 14] Previous experimental and theoretical studies on the p-dianisyl carbo-benzene 1, [12d] that is, the central-ring carbo-mer of the p-terphenyl fluorophore 2 (Figure 1), suggested 1 as ap romising 2PAc andidate. [15] Unlike 2,h owever, 1 is not fluorescent, andt his prevents 2PAc rosssection measurements by the two-photon excitation fluorescence method. [16] Moreover, the poor solubility of 1 prevented the determination of s 2PA by the alternative Z-scan method, which requires the use of highly concentrated (10 À2 m)s olutions of the chromophore.…”

Section: Introductionmentioning

confidence: 99%

Difluorenyl carbo‐Benzenes: Synthesis, Electronic Structure, and Two‐Photon Absorption Properties of Hydrocarbon Quadrupolar Chromophores

Baglai

Anda-Villa

Barba-Barba

et al. 2015

Chemistry A European J

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The synthesis, crystal and electronic structures, and one- and two-photon absorption properties of two quadrupolar fluorenyl-substituted tetraphenyl carbo-benzenes are described. These all-hydrocarbon chromophores, differing in the nature of the linkers between the fluorenyl substituents and the carbo-benzene core (C-C bonds for 3 a, C-C=C-C expanders for 3 b), exhibit quasi-superimposable one-photon absorption (1PA) spectra but different two-photon absorption (2PA) cross-sections σ2PA. Z-scan measurements (under NIR femtosecond excitation) indeed showed that the C≡C expansion results in an approximately twofold increase in the σ2PA value, from 336 to 656 GM (1 GM = 10(-50) cm(4) s molecule(-1) photon(-1)) at λ = 800 nm. The first excited states of Au and Ag symmetry accounting for 1PA and 2PA, respectively, were calculated at the TDDFT level of theory and used for sum-over-state estimations of σ2PA(λi), in which λi = 2 hc/Ei, h is Planck's constant, c is the speed of light, and Ei is the energy of the 2PA-allowed transition. The calculated σ2PA values of 227 GM at 687 nm for 3 a and 349 GM at 708 nm for 3 b are in agreement with the Z-scan results.

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Cyclic Ether Auxofluors on Oligophenylene Laser Dyes

Cited by 12 publications

References 19 publications

“Carbo-aromaticity” and novel carbo-aromatic compounds

“Carbo-aromaticity” and novel carbo-aromatic compounds

Variation of aromaticity by twisting or expanding the ring content

Difluorenyl carbo‐Benzenes: Synthesis, Electronic Structure, and Two‐Photon Absorption Properties of Hydrocarbon Quadrupolar Chromophores

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