Multi-fold Sonogashira coupling: a new and convenient approach to obtain tetraalkynyl anthracenes with tunable photophysical properties

Islam, Khadimul; Narjinari, Himani; Bisarya, Akshara; Kumar, Akshai

doi:10.1039/d1ob01861b

Cited by 4 publications

(3 citation statements)

References 59 publications

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“…Interestingly while Kwon and co‐workers [17c] reported a four‐step synthetic route to tetrabromoanthracene derivatives using Pd(PPh 3 ) 4 as catalyst with an overall yield of 13.4 %, the Moorthy group used the same catalyst to synthesize similar derivatives in five steps with an overall yield of 14.2 % [17b] . With an objective to formulate a cost‐effective high‐yield route to several new 2,6,9,10‐ tetrabromoanthracenes, we set out to explore the Ni(II) salt catalyzed tetra‐fold Suzuki coupling of tetrabromoanthracene [17d] with phenyl boronic acid (Table 3).…”

Section: Resultsmentioning

confidence: 99%

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Nickel Bromide Catalyzed Ligand‐Free and Activator‐less Suzuki Coupling Reactions

et al. 2022

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Readily available and inexpensive bromide salt based on earthabundant nickel has been used to catalyze the Suzuki coupling of a variety of aryl halides (ca. 37 examples) in high yields under ambient conditions with good functional group tolerance. The reactivity of various aryl halides follows the corresponding CÀ X (X = I, Br and Cl) bond strength in the order ArÀ I > ArÀ Br > ArÀ Cl. EPR analysis, mercury-drop experiments and reactions with radical scavenger such as TEMPO point to the involvement of well-defined molecular species that operate via a Ni(0)/Ni(II) catalytic cycle where oxidative addition of the aryl halide to Ni(0) is likely to be the rate-determining-step (RDS). For the first time, valuable new polycyclic aromatic hydrocarbons (PAHs) with exciting photophysical properties have been synthesized (ca. 23 examples) via a Ni(II) catalyzed multi-fold Suzuki coupling.

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Section: Resultsmentioning

confidence: 99%

“…[a] The absorption (3×10 −5 M) as well as emission (6×10 −6 M) spectra recorded in CHCl 3 . [b] Quantum yield were calculated with respect to quinine sulfate in 0.1 M H 2 SO 4 as standard (ϕ=54 %) [17d] . [c] The band‐gaps were calculated from Tauc plot.…”

Section: Resultsmentioning

confidence: 99%

Nickel Bromide Catalyzed Ligand‐Free and Activator‐less Suzuki Coupling Reactions

et al. 2022

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“…Compared with their corresponding polymer counterparts, organic small molecules are of continuous interest to the academic community because of their attractive advantages such as well-defined molecular structures, better crystallinity, convenient large-scale preparation, and better batch-to-batch reproducibility. − Over the past few decades, numerous π-conjugated organic small molecules have been developed for their intriguing photophysical properties and potential applications as fluorescent probes, − organic solar cells, − ,− and modular building blocks, − etc. Among them, thiophene-based π-conjugated organic small molecules have attracted increasing attention owing to their remarkable electrical and optical features. − …”

Section: Introductionmentioning

confidence: 99%

Positional Isomeric Thiophene-Based π-Conjugated Chromophores: Synthesis, Structure, and Optical Properties

Yi,

Qin,

Zhai

et al. 2023

Precision Chemistry

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A series of positional isomeric chromophores o-TC, m-TC, and p-TC, in which electron-rich thiophene moieties were connected by π-conjugated bridges, were divergently synthesized and characterized. Single-crystal X-ray diffraction analysis revealed an intriguing zipper-like packing mode which was adopted by m-TC in the solid state. Subsequently, UV−vis absorption spectra and fluorescence spectra in a series of solvents were investigated. The nearly coplanar para isomer p-TC was found to have the most intense UV−vis absorption, fluorescence emission, and the highest photoluminescence quantum yield. The molecule structure, electronic nature, and origination of the absorption of p-TC were revealed through density functional theory calculations. Interestingly, all three positional isomers exhibited strong and stable electrochemiluminescence emission, which enriched the existing knowledge on the optical properties of thiophene-based oligomers.

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Room-Temperature, Copper-Free, and Amine-Free Sonogashira Reaction in a Green Solvent: Synthesis of Tetraalkynylated Anthracenes and In Vitro Assessment of Their Cytotoxic Potentials

et al. 2023

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The multifold Sonogashira coupling of a class of aryl halides with arylacetylene in the presence of an equivalent of Cs 2 CO 3 has been accomplished using a combination of Pd(CH 3 CN) 2 Cl 2 (0.5 mol %) and cataCXium A (1 mol %) under copperfree and amine-free conditions in a readily available green solvent at room temperature. The protocol was used to transform several aryl halides and alkynes to the corresponding coupled products in good to excellent yields. The rate-determining step is likely to involve the oxidative addition of Ar-X. The green protocol provides access to various valuable polycyclic aromatic hydrocarbons (PAHs) with exciting photophysical properties. Among them, six tetraalkynylated anthracenes have been tested for their anticancer properties on the human triple-negative breast cancer (TNBC) cell line MDA-MB-231 and human dermal fibroblasts (HDFs). The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay was performed to find out the IC 50 concentration and lethal dose. The compounds being intrinsically fluorescent, their cellular localization was checked by live cell fluorescence imaging. 4′,6-Diamidino-2-phenylindole (DAPI) and propidium iodide (PI) staining was performed to check apoptosis and necrosis, respectively. All of these studies have shown that anthracene and its derivatives can induce cell death via DNA damage and apoptosis.

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Multi-fold Sonogashira coupling: a new and convenient approach to obtain tetraalkynyl anthracenes with tunable photophysical properties

Abstract: For the first time a direct single-step one-pot route to access nine new symmetric tetraalkynylated anthracenes via the Pd(CH3CN)2Cl2/ cataCXium®A catalyzed tetra-fold Sonogashira coupling is reported. Five of these tetraalkynylated...

Cited by 4 publications

References 59 publications

Nickel Bromide Catalyzed Ligand‐Free and Activator‐less Suzuki Coupling Reactions

Nickel Bromide Catalyzed Ligand‐Free and Activator‐less Suzuki Coupling Reactions

Positional Isomeric Thiophene-Based π-Conjugated Chromophores: Synthesis, Structure, and Optical Properties

Room-Temperature, Copper-Free, and Amine-Free Sonogashira Reaction in a Green Solvent: Synthesis of Tetraalkynylated Anthracenes and In Vitro Assessment of Their Cytotoxic Potentials

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