Synthesis of conjugated 2 and 2,5-(ethenyl) and (ethynyl)phenylethynyl thiophenes: fluorescence properties

The synthesis of two [4]-dendralene compounds incorporating thiophene-(p-nitrophenyl) donor–acceptor units is presented. The dendralenes adopt two different conformers in solution and solid state and the transformation between the structures can be controlled by light and heat. The electron-donating components of the dendralenes are represented by bromothienyl (in 13) and ethylenedioxythiophene(EDOT)-thienyl (in 15) end-groups. The most facile transformation involves the isomerisation of donor–acceptor conjugated systems (a conformers) into structures in which only the thiophenes are conjugated (b conformers), and this process is driven by ambient light. The structures of the two conformers of compound 13 are confirmed by single-crystal X-ray diffraction studies and the structural changes in both compounds have been monitored by 1H NMR spectroscopy and absorption studies. The transformations were found to be first-order processes with rate constants of k = 0.0027 s−1 and k = 0.00022 s−1 for 13 and 15, respectively. Density functional theory calculations at the B3LYP/6-31G∗ level give credence to the proposed mechanism for the a→b conversion, which involves photoinduced intramolecular charge transfer (ICT) as the key step. The EDOT derivative (15) can be polymerised by electrochemical oxidation and a combination of cyclic voltammetry and UV/Vis spectroelectrochemical experiments indicate that the a conformer can be trapped and stabilised in the solid state.

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“…The spectroscopic properties of 23 have been reported elsewhere 70. The λ max is reported at 381 nm in CH 2 Cl 2 .…”

Section: Resultsmentioning

confidence: 99%

Controlling the Conformational Changes in Donor–Acceptor [4]‐Dendralenes through Intramolecular Charge‐Transfer Processes

Kanibolotsky

Forgie

McEntee

et al. 2009

Chemistry A European J

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“…A number of bis(phenylethynyl)thiophenes (BPETs) have been reported and are of interest due to their luminescence [114][115][116][117][118][119] and non-linear optical [120][121][122] properties and also, due to the bent nature of the thiophene moiety, their liquid crystal phase behavior [123][124][125][126]. There are a number of routes for the synthesis of BPETs.…”

Section: Bis(arylethynyl) Thiophenesmentioning

confidence: 99%

“…There are a number of routes for the synthesis of BPETs. The most straightforward methods utilize catalytic Sonogashira or Kumada-Tamao cross-couplings of terminal alkynes [114][115][116][117][118] or alkynyl Grignard reagents [127], Fig. 61.…”

Section: Bis(arylethynyl) Thiophenesmentioning

confidence: 99%

Dibenzometallacyclopentadienes, boroles and selected transition metal and main group heterocyclopentadienes: Synthesis, catalytic and optical properties

Steffen

Ward

Jones

et al. 2010

Coordination Chemistry Reviews

113

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“…2017, 23,1623 -1633 www.chemeurj.org 2017 Wiley-VCH Verlag GmbH &Co. KGaA, Weinheim previously described. [26] Click reaction Generalprocedure Scaffold 8,12,15,18,19,o r21,C uSO 4 ·5H 2 O( 0.3 equiv/alkyne) and sodium ascorbate (0.3 eqiv/alkyne) were dissolved in DMF/H 2 O (9:1). [17,18] VAAw as purified by affinity chromatography on lactosylated Sepharose 4B, obtained after activation by divinyl sulfone, checked for purity by one-and two-dimensional gel electrophoresis and for activity by haemagglutination, solid-phase assays and cell toxicity.…”

Section: Materials and Reagentsmentioning

confidence: 99%

Direct Enzymatic Branch‐End Extension of Glycocluster‐Presented Glycans: An Effective Strategy for Programming Glycan Bioactivity

Bayón

Deir‐Kaspar

et al. 2016

Chemistry A European J

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The sequence of a glycan and its topology of presentation team up to determine the specificity and selectivity of recognition by saccharide receptors (lectins). Structure-activity analysis would be furthered if the glycan part of a glycocluster could be efficiently elaborated in situ while keeping all other parameters constant. By using a bacterial α2,6-sialyltransferase and a small library of bi- to tetravalent glycoclusters, we illustrate the complete conversion of scaffold-presented lactoside units into two different sialylated ligands based on N-acetyl/glycolyl-neuraminic acid incorporation. We assess the ensuing effect on their bioactivity for a plant toxin, and present an analysis of the noncovalent substrate binding contacts that the added sialic acid moiety makes to the lectin. Enzymatic diversification of a scaffold-presented glycan can thus be brought to completion in situ, offering a versatile perspective for rational glycocluster engineering.

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Synthesis of conjugated 2 and 2,5-(ethenyl) and (ethynyl)phenylethynyl thiophenes: fluorescence properties

Cited by 20 publications

References 43 publications

Controlling the Conformational Changes in Donor–Acceptor [4]‐Dendralenes through Intramolecular Charge‐Transfer Processes

Controlling the Conformational Changes in Donor–Acceptor [4]‐Dendralenes through Intramolecular Charge‐Transfer Processes

Dibenzometallacyclopentadienes, boroles and selected transition metal and main group heterocyclopentadienes: Synthesis, catalytic and optical properties

Direct Enzymatic Branch‐End Extension of Glycocluster‐Presented Glycans: An Effective Strategy for Programming Glycan Bioactivity

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