Synthesis and Properties of Functional Twisted Tolanes

Kozhemyakin, Yury; Kretzschmar, Andreas; Krämer, Maximilian; Röminger, Frank; Dreuw, Andreas; Bunz, Uwe H. F.

doi:10.1002/chem.201701519

Cited by 6 publications

(4 citation statements)

References 31 publications

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“…The origin for this effect lies in the relatively low‐lying π π*,LUMO of the acetylenic unit ( ε = −1.78 eV) which admixes in a bonding fashion with the higher lying NH 2π*,LUMO of the aniline fragment ( ε = −0.88 eV). Experimental studies on the effects of substituting X/Y on diphenylacetylene (c.f., D1‐π‐A1), which exhibits a large fluorescence quantum yield ( Φ F = 0.50) at low temperature implying good emission properties as well, have also shown that increasing the donor–acceptor strength causes an increase in the absorption wavelength maximum and hyperpolarizability …”

Section: Resultsmentioning

confidence: 99%

Rational design of near‐infrared absorbing organic dyes: Controlling the HOMO–LUMO gap using quantitative molecular orbital theory

et al. 2018

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Principles are presented for the design of functional near‐infrared (NIR) organic dye molecules composed of simple donor (D), spacer (π), and acceptor (A) building blocks in a D‐π‐A fashion. Quantitative Kohn–Sham molecular orbital analysis enables accurate fine‐tuning of the electronic properties of the π‐conjugated aromatic cores by effecting their size, including silaaromatics, adding donor and acceptor substituents, and manipulating the D‐π‐A torsional angle. The trends in HOMO–LUMO gaps of the model dyes correlate with the excitation energies computed with time‐dependent density functional theory at CAMY‐B3LYP. Design principles could be developed from these analyses, which led to a proof‐of‐concept linear D‐π‐A with a strong excited‐state intramolecular charge transfer and a NIR absorption at 879 nm. © 2018 The Authors. Journal of Computational Chemistry published by Wiley Periodicals, Inc.

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Section: Resultsmentioning

confidence: 99%

Rational design of near‐infrared absorbing organic dyes: Controlling the HOMO–LUMO gap using quantitative molecular orbital theory

et al. 2018

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“…The emissive quantum yield ( n ‐hexane, 0.01) is low, but easily measurable. The emissive life time is τ =0.2 ns fairly short; planar and singly tethered tolanes have emissive lifetimes ( n ‐hexane) of 0.4 ns ,…”

Section: Methodsmentioning

confidence: 99%

A Tethered Tolane: Twisting the Excited State

Kozhemyakin

Krämer

Röminger

et al. 2018

Chemistry A European J

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The synthesis of a doubly bridged tolane is reported. The target is obtained in a five-step synthesis, starting from commercially available 2-amino-meta-xylene by a combination of a Sandmeyer reaction, radical bromination, and Stille-type coupling, followed by double ring closing. The doubly tethered tolane is crystalline; the two phenyl rings are highly twisted with respect to each other both in solution and in the solid state. Optical spectroscopy and quantum chemical calculations show that the doubly bridged tolane is twisted not only in the ground state, but also in the excited state, leading to emission from the twisted state in solution and in the solid state. Strong phosphorescence is observed at cryogenic temperatures.

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“…Sonogashira reaction was discovered in 1975 [ 105 ] and represents a fascinating route to various alkynes. Sonogashira cross coupling of acetylene with iodo- and bromoarenes can be successfully applied to obtain symmetric diaryl ethynes [ 42 , 106 , 107 , 108 ]. For example, palladium-catalyzed Sonogashira coupling of acetylene with methyl 4-iodobenzoate ( 51 ) gives 4,4′-(1,2-ethynediyl)-bisbenzoic acid ( 52 ), a comonomer for the synthesis of liquid crystalline polymer ( Scheme 27 ) [ 107 ].…”

Section: Acetylene In Organic Synthesismentioning

confidence: 99%

Acetylene in Organic Synthesis: Recent Progress and New Uses

et al. 2018

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Recent progress in the leading synthetic applications of acetylene is discussed from the prospect of rapid development and novel opportunities. A diversity of reactions involving the acetylene molecule to carry out vinylation processes, cross-coupling reactions, synthesis of substituted alkynes, preparation of heterocycles and the construction of a number of functionalized molecules with different levels of molecular complexity were recently studied. Of particular importance is the utilization of acetylene in the synthesis of pharmaceutical substances and drugs. The increasing interest in acetylene and its involvement in organic transformations highlights a fascinating renaissance of this simplest alkyne molecule.

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Synthesis and Properties of Functional Twisted Tolanes

Cited by 6 publications

References 31 publications

Rational design of near‐infrared absorbing organic dyes: Controlling the HOMO–LUMO gap using quantitative molecular orbital theory

Rational design of near‐infrared absorbing organic dyes: Controlling the HOMO–LUMO gap using quantitative molecular orbital theory

A Tethered Tolane: Twisting the Excited State

Acetylene in Organic Synthesis: Recent Progress and New Uses

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