Theoretical study of structural and electronic properties of oligo(thiophene-phenylene)s in comparison with oligothiophenes and oligophenylenes

Zgou, H.; Bouzzine, Si Mohamed; Bouzakraoui, Saïd; Hamidi, Mohamed; Bouachrine, Mohammed

doi:10.1016/j.cclet.2007.10.011

Cited by 20 publications

(11 citation statements)

References 16 publications

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“…For the bridged or unbridged mono or heterocyclic polymers, comparisons between the theoretical and the experimental results are available in the literature. Previously published results show that while the computed energy gaps differ in the range of 4-5 eV for dimers and 2.5-3.5 eV for hexamers, the experimental gaps were found to be in between 2.0-3.0 eV for polymers [34][35][36][37][38][39]. When those published data and our results have been compared, we may conclude that our title polymer is expected to have larger energy gap with respect to bridged or unbridged mono or heterocyclic polymers.…”

Section: Theoretical Electronic Propertiesmentioning

confidence: 66%

FTIR, Raman and NMR spectroscopic and DFT theoretical studies on poly(N-vinylimidazole)

Talu

Demiroğlu

Yurdakul

et al. 2015

Spectrochimica Acta Part A: Molecular and Biomolecular Spectros

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Section: Theoretical Electronic Propertiesmentioning

confidence: 66%

FTIR, Raman and NMR spectroscopic and DFT theoretical studies on poly(N-vinylimidazole)

Talu

Demiroğlu

Yurdakul

et al. 2015

Spectrochimica Acta Part A: Molecular and Biomolecular Spectros

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“…The bands featured in the 300-550nmr egion were investigated in this study because these bands were most clearly identified.N SB showeda similar absorption maximum as X-34, assigning to the p-p* transition, whereas the absorption maximum of TSB was 35 nm redshifted due to an enhanced planarity and conjugation length through the backbonec omparedw ith X-34. [23][24][25] QSB and BTDSB, which have donor-p-acceptor-p-donor (D-p-Ap-D)-typee lectronics tructure, displayed two absorption maxima. The use of nitrogen-containing heterocyclics as effective electron acceptors has been reported previously.…”

Section: Resultsmentioning

confidence: 99%

Detection and Imaging of Aβ1‐42 and Tau Fibrils by Redesigned Fluorescent X‐34 Analogues

Zhang

Sandberg

Konsmo

et al. 2018

Chemistry A European J

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We revisited the Congo red analogue 2,5-bis(4'-hydroxy-3'-carboxy-styryl)benzene (X-34) to develop this highly fluorescent amyloid dye for imaging Alzheimer's disease (AD) pathology comprising Aβ and Tau fibrils. A selection of ligands with distinct optical properties were synthesized by replacing the central benzene unit of X-34, with other heterocyclic moieties. Full photophysical characterization was performed, including recording absorbance and fluorescence spectra, Stokes shift, quantum yield and fluorescence lifetimes. All ligands displayed high affinity towards recombinant amyloid fibrils of Aβ1-42 (13-300 nm K ) and Tau (16-200 nm K ) as well as selectivity towards the corresponding disease-associated protein aggregates in AD tissue. We observed that these ligands efficiently displaced X-34, but not Pittsburgh compound B (PiB) from recombinant Aβ1-42 amyloid fibrils, arguing for retained targeting of the Congo red type binding site. We foresee that the X-34 scaffold offers the possibility to develop novel high-affinity ligands for Aβ pathology found in human AD brain in a different mode compared with PiB, potentially recognizing different polymorphs of Aβ fibrils.

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“…In addition, from the histology experiments, the level of conformational freedom along the conjugated backbone was identified as a novel criterion for spectral separation of Aβ aggregates and NFTs. To verify all these findings, p-FTAA was subjected to further molecular engineering and as phenyl moieties previously have been utilized to disrupt the planarity of oligothiophenes, 41 – 43 two co-oligomers termed p-FTAA-Ph and p-FTAA-MeOPh with the central thiophene ring replaced with a phenyl ring, were synthesized (Figure 4 , Scheme 4 ). The aim with these designs was to create pentameric analogues to p-FTAA that have a nonplanar backbone with a disrupted conjugation length as well as a sterically restricted center.…”

Section: Resultsmentioning

confidence: 99%

The Structural Basis for Optimal Performance of Oligothiophene‐Based Fluorescent Amyloid Ligands: Conformational Flexibility is Essential for Spectral Assignment of a Diversity of Protein Aggregates

Klingstedt¹,

Shirani²,

Åslund³

et al. 2013

Chemistry A European J

146

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Protein misfolding diseases are characterized by deposition of protein aggregates, and optical ligands for molecular characterization of these disease-associated structures are important for understanding their potential role in the pathogenesis of the disease. Luminescent conjugated oligothiophenes (LCOs) have proven useful for optical identification of a broader subset of disease-associated protein aggregates than conventional ligands, such as thioflavin T and Congo red. Herein, the molecular requirements for achieving LCOs able to detect nonthioflavinophilic Aβ aggregates or non-congophilic prion aggregates, as well as spectrally discriminate Aβ and tau aggregates, were investigated. An anionic pentameric LCO was subjected to chemical engineering by: 1) replacing thiophene units with selenophene or phenylene moieties, or 2) alternating the anionic substituents along the thiophene backbone. In addition, two asymmetric tetrameric ligands were generated. Overall, the results from this study identified conformational freedom and extended conjugation of the conjugated backbone as crucial determinants for obtaining superior thiophene-based optical ligands for sensitive detection and spectral assignment of disease-associated protein aggregates.

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Theoretical study of structural and electronic properties of oligo(thiophene-phenylene)s in comparison with oligothiophenes and oligophenylenes

Cited by 20 publications

References 16 publications

FTIR, Raman and NMR spectroscopic and DFT theoretical studies on poly(N-vinylimidazole)

FTIR, Raman and NMR spectroscopic and DFT theoretical studies on poly(N-vinylimidazole)

Detection and Imaging of Aβ1‐42 and Tau Fibrils by Redesigned Fluorescent X‐34 Analogues

The Structural Basis for Optimal Performance of Oligothiophene‐Based Fluorescent Amyloid Ligands: Conformational Flexibility is Essential for Spectral Assignment of a Diversity of Protein Aggregates

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