Effect of end substitution on electrochemical and optical properties of oligothiophenes

Garcia, P.; Pernaut, Jean Michel; Hapiot, Philippe; Wintgens, Véronique; Valat, P.; Garnier, F.; Delabouglise, Didier

doi:10.1021/j100104a040

Cited by 146 publications

(117 citation statements)

References 2 publications

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“…The quantum yields of the terthiophene nucleoside 3a and the free terthiophene 7 are about the same as the reported quantum yield for free terthiophene [27], and the quantum yield of pyrene nucleoside 3d is similar to that of pyrene-1-butanoic acid. However, the quantum yield we measured is ca.…”

supporting

confidence: 79%

Novel Nucleoside Analogues with Fluorophores Replacing the DNA Base

Strässler

Davis

Kool

1999

HCA

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We describe the preparation and fluorescence properties of a set of new nucleosides in which a known hydrocarbon or oligothiophene fluorophore replaces the DNA base at C(1) of the deoxyribose moiety (see 3a -f). These compounds are potentially useful as probes in the study of the structure and dynamics of nucleic acids and their complexes with proteins. In addition, they may find use as fluorescent labels for nucleic-acid-based biomedical diagnostics methods. The fluorophores conjugated to deoxyribose at C(1) in the α-D-form include terphenyl, stilbene, terthiophene, benzoterthiophene, and pyrene. Also included is a non-fluorescent spacer in which cyclohexene replaces the DNA base. The nucleosides are derived from brominated fluorophore precursors and Hoffer's 2-deoxy-3,5-di-O-(p-toluoyl)-D-ribofuranosyl chloride. The emission maxima of the free nucleosides range from 345 to 536 nm. Also described are the 5′-(dimethoxytrityl) 3′-O-phosphoramidite derivatives 5a -f, suitable for incorporation into oligonucleotides by automated synthesizers.We have taken a related approach to developing new fluorescent labels for DNA [10]. Rather than modifying an existing DNA base, however, we have simply replaced it by another flat aromatic structure, i.e.

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supporting

confidence: 79%

Novel Nucleoside Analogues with Fluorophores Replacing the DNA Base

Strässler

Davis

Kool

1999

HCA

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“…24 The structural distortion is reflected on the energy gap. For the 2T in the anti conformation, the experimental E 0 0 is 3.68 eV 25 values at SVWN/6-31G(d)//HF/6-31G(d) level were found to be 4.05 eV for alkyl side chain longer than propyl, being higher than the value calculated for the syn conformation, which was 3.86 eV (see Table 1). The corresponding values for anti HH isomers were constant and equal to 4.35 eV ( Table 2).…”

Section: Resultsmentioning

confidence: 78%

Structure and electronic properties of alkylthiophenes coupled by Head-to-Tail and Head-to-Head regioselectivity

Oliveira¹,

Almeida²,

Santos³

2004

J. Braz. Chem. Soc.

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No presente artigo, métodos teóricos foram utilizados na análise da estrutura e propriedades eletrônicas de oligômeros de alquiltiofenos considerando diferentes regiosseletividades. A lacuna de energia entre as bandas de valência e condução foi calculada nos níveis ab initio Hartree-Fock (HF) e teoria do funcional de densidade (DFT) e semi-empírico ZINDO/S-CI. Os resultados mostraram que o isômero Head-Head-Tail-Tail (HH-TT) apresenta menores valores para a lacuna de energia quando oligômeros com mais de três unidades monoméricas são considerados e que a substituição do anel tiofeno por grupos alquila não afeta significativamente a lacuna de energia. Esse resultado é importante no sentido que mostra que polímeros mais processáveis podem ser obtidos através da alquilação sem perda considerável de suas características condutoras.In the present paper a theoretical analysis of alkylthiophenes with Head-Tail-Head-Tail (HT-HT) and Head-Head-Tail-Tail (HH-TT) regioselectivities up to 6 monomeric units was carried out. Structure and electronic properties for the syn and anti forms were calculated by ab initio HartreeFock (HF) and Density Functional Theory (DFT) approaches. The energy gap between the conduction and valence bands was obtained at HF and DFT levels and also calculated with the semiempirical ZINDO/S-CI method. The results showed that the isomer with HH-TT regioselectivity presents lower energy gap for longer oligomers and the substitution of thiophene by alkyl groups does not change significantly the energy gap. This is important in the sense that more processable polymers can be obtained through alkylation without decrease the energy gap that is a molecular properties related to the electronic conductivity. Regarding to the conformational equilibrium, the syn form was found to be stable only for the HT-HT isomer and in this case the energy gap was found to be lower than those calculated for the anti form.

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“…The a-end-capping of the terthiophene by the bromo groups stabilizes the radical cation. [19] Thus, we obtained reversible CV waves in the oxidation part (Figure 7a and b). The half-wave potentials for 3 TBr-b-DEG and 3 TBr-b-Rx are + 1.15 V and + 1.40 V, respectively.…”

Section: Electrochemistry Of Terthiophene [2]rotaxane 3 Tbr-b-rxmentioning

confidence: 83%

“…These values are comparable to the reported ones for 3 T and 3 TBr (5.5 and 1.9 %, respectively). [19] Inclusion complexation of terthiophene threads with CBPQT 4 + ·4 PF 6 : When CBPQT 4 + ·4 PF 6 was added to a solution of 3 T-b-DEG or 3 TBr-b-DEG, the color of the solution changed immediately from yellow to red purple, indicating the formation of pseudo-rotaxane.…”

Section: Resultsmentioning

confidence: 99%

β‐Substituted Terthiophene [2]Rotaxanes

Ikeda

Higuchi

Kurth

2009

Chemistry A European J

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Two kinds of beta-substituted terthiophene [2]rotaxanes were synthesized using the host-guest pairs of the electron-deficient cyclophane cyclobis(paraquat-p-phenylene) (CBPQT(4+)) and the electron-rich terthiophenes with diethyleneglycol chains at the beta-position. One is made from the alpha-position non-substituted terthiophene (3 T-beta-Rx) and the other is made from the alpha-dibromo-substituted terthiophene (3 TBr-beta-Rx). The binding constants of the beta-substituted terthiophene threads were confirmed to be smaller than that of the alpha-substituted terthiophene analogue. By UV/Vis absorption measurements, we confirmed the charge-transfer (CT) band in the visible region with an extinction coefficient of approximately 10(2) (M(-1) cm(-1)). Strong, but not quantitative, quenching of the terthiophene fluorescence was confirmed for the [2]rotaxanes. Although the beta-substituted terthiophene thread was electrochemically polymerizable, the [2]rotaxane 3 T-beta-Rx was not polymerizable. This result indicates that the interlocked CBPQT(4+) macrocycle effectively suppresses the electrochemical polymerization of the terthiophene unit because electrostatic repulsive and steric effects of CBPQT(4+) hinder the dimerization of the terthiophene radical cations. In the electrochemical measurement, we confirmed the shift of the first reduction peak towards less negative potential compared to free CBPQT(4+) and the splitting of the second reduction peak. These electrochemical behaviors are similar to those observed for the highly-constrained [2]rotaxanes. The beta-substituted terthiophene [2]rotaxanes reported herein are important key compounds to prepare polythiophene polyrotaxanes.

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Effect of end substitution on electrochemical and optical properties of oligothiophenes

Cited by 146 publications

References 2 publications

Novel Nucleoside Analogues with Fluorophores Replacing the DNA Base

Novel Nucleoside Analogues with Fluorophores Replacing the DNA Base

Structure and electronic properties of alkylthiophenes coupled by Head-to-Tail and Head-to-Head regioselectivity

β‐Substituted Terthiophene [2]Rotaxanes

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