Oligothiophene – immer länger? Synthese, Charakterisierung und rastertunnelmikroskopische Abbildung von homologen, isomerenreinen Oligo(alkylthiophenen)

Bäuerle, Peter; Fischer, Thomas; Bidlingmeier, Bernd; Stabel, Andreas; Rabe, Jürgen P.

doi:10.1002/ange.19951070310

Cited by 61 publications

(27 citation statements)

References 31 publications

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“…22,23,[29][30][31] For fair comparison, we also estimated the ECL with this method. Figure 2b shows the correlation between absorption energy (E max ) and inverse phenyl ring numbers (m).…”

mentioning

confidence: 99%

Iterative Binomial Synthesis of Monodisperse Polyfluorenes up to 64-mers and Their Chain-Length-Dependent Properties

Wang

Tian

et al. 2011

Macromolecules

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C onjugated polymers have emerged as one class of advanced materials due to their applications in optoelectronic devices and sensors. 1-4 However, various fundamental issues, such as crystalline structures and chain-length-related properties, still need further study for understanding insight from the polymer viewpoint. [5][6][7][8][9][10] In principle, polymer samples with well-defined chain length and chemical structures and narrow molecular weight distribution are preferable in studying these fundamental issues. However, synthesis of well-defined conjugated polymers by polymerizations has been only realized for limited conjugated systems to date. 11,12 As one class of the most important conjugated polymers, polyfluorenes with defined molecular weights and narrow molecular weight distributions are still difficult to be prepared.Monodisperse conjugated oligomers (MCOs) are characterized with well-defined and uniform chemical structures. 13,14 These characteristics enable them as the ideal model compounds to attain specific information, such as effective conjugation length (ECL), of their corresponding polydisperse high molecular weight analogues by extrapolation. 15,16 However, the molecular weights of the most of MCOs reported today locate in the oligomeric region since the synthesis of MCOs is a multistep process and requires carefully optimizing the reaction condition and synthetic strategy. 17-23 Their molecular weights are not high enough to serve as models of the corresponding conjugated polymers in all cases. In this regard, synthesis of monodisperse conjugated polymers (MCPs) with molecular weights beyond 10 000 g/mol is very important. Two series of MCPs based on thiophene and fluorene units with the molecular weights beyond 20 000 g/mol have been reported. 24,25 However, these MCPs were separated from the polymerization mixtures of macromonomers by preparative gel permeation chromatography (PGPC), and the methods do not allow preparing MCPs in a relatively large quantity.The iterative binomial approach is most efficient in the synthesis of MCOs. 13,17,18 However, it has not been used in the preparation of MCPs yet. After carefully optimizing the reaction conditions, in the current paper, we first successfully synthesized monodisperse poly(9,9-dioctylfluorene)s (POFs) with molecular weights up to 25 018 g/mol in half-gram scale via iterative binomial approach. In THF, the R value of POFs in the Mark-Houwink equation was measured to be 1.15. Absorption spectroscopic measurements indicate that absorption maxima of POFs do not reach the convergent limit yet up to 64-mer, indicating that POFs are highly conjugated.The structures of the monodisperse POFs, i.e. SiFnSi and Fn, are depicted in Chart 1, where n and Si represent the number of fluorene units and the terminal SiMe 3 group, respectively. Synthesis of SiFnSi and Fn is outlined in Scheme 1. In general, two orthogonal protecting groups are required in iterative binomial synthesis of MCOs, as exemplified by the synthesis of oligo(p-phenyleneethynylene)s...

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“…22,23,[29][30][31] For fair comparison, we also estimated the ECL with this method. Figure 2b shows the correlation between absorption energy (E max ) and inverse phenyl ring numbers (m).…”

mentioning

confidence: 99%

Iterative Binomial Synthesis of Monodisperse Polyfluorenes up to 64-mers and Their Chain-Length-Dependent Properties

Wang

Tian

et al. 2011

Macromolecules

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“…[20,21] The precursor, didodecyl-substituted quaterthiophene 5, is known to self-organize into highly regular suprastructures on surfaces [22] and in the bulk. [6a] Synthesis of the semiconductor block and the final oligothiophene-peptide hybrid 8 are shown in Scheme 1b.…”

mentioning

confidence: 99%

Oligothiophene Versus β‐Sheet Peptide: Synthesis and Self‐Assembly of an Organic Semiconductor‐Peptide Hybrid

et al. 2009

Self Cite

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Investigation of self-organization behavior of organic (semi)-conductors became very important recently, since their physical properties and performance in organic electronic devices strongly depend on ordering effects, on both molecular and nanoscale levels. [1] In this respect, bioinspired functionalization of conjugated systems might greatly enhance the diversity of electronically interesting assemblies, and potentially allow for the rational design of hierarchically ordered nanostructures.[2] Thus, from possible hybrids of conjugated backbones, the combination of oligo-or polythiophenes with biomolecules, such as nucleotides, [3] carbohydrates, [4] or peptides, [5] are interesting. Particularly, the latter appears to be attractive, because interplay between different intermolecular forces in the peptide and oligothiophene segments results in competing self-assembly motifs. Hence, very specific organization properties can be expected. Whereas thiophene-based materials typically form well-organized 2D lamellar superstructures due to van der Waals interactions of alkyl side chains, and stack into the third dimension via p-p interactions, [6] secondary structures of peptides, preferentially bsheets or a-helices, are governed by stronger and directed hydrogen-bond formation.[7] The high tendency of peptides to adopt well-defined secondary-structure motifs has been exploited recently to guide self-organization of a broad range of synthetic polymers.[8] Attention has mainly been devoted to the b-sheet motif, leading to anisotropic fibrillar or fiber-like structures. [9] However, other highly interesting assembly motifs, for example the coiled-coil motif, were exploited, resulting in distinct nanoobjects by the lateral assembly of amphiphilic a-helices. [10] We recently presented the first conjugate between a regioregularly alkylated quaterthiophene and a pentapeptide consisting of a silk-inspired sequence of alanine-glycine repeats, which is known to adopt b-sheet structures.[5a] Unexpected and novel 3D nanostructures were found, suggesting that short peptide sequences may indeed influence the nanoscale structure, and ultimately, properties of organic semiconducting materials.The versatility of this class of hybrid oligo-/polymers is certainly not exploited, considering the diversity of both the conjugated oligo-/polymer platforms and the bioorganic segments. It becomes increasingly evident that such materials will envelop by far more structural and functional space as, for example, common AB-block copolymer systems.[11]Here, we present the synthesis and self-organization behavior of a symmetrically substituted A-B-A-type bioinspired semiconductor, quaterthiophene-peptide hybrid 8 (Scheme 1b), by combining a central quaterthiophene segment (B) with two peptide-poly(ethylene oxide) bioconjugates (A).As outlined in Scheme 1, the oligothiophene segment was substituted on both sides with an amino acid sequence Gly-(ThrVal) 3 -Gly-aPhe-Gly (Scheme 1, structure 2), with Gly ¼ glycine, Val ¼ valine, Thr ¼ threonine, ...

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“…The dimerization enthalpy which was determined either by UV/VIS/NIR or EPR increases as the chain length increases. The experiments showed that radical cations of very long oligomers are almost completely dimerized at room temperature and show only weak EPR activity (see above) [169]. The correlation of the transition energies obtained for the ECnT monomeric and dimeric radical cations 283-285 also exhibit a linear dependence with the inverse chain length.…”

Section: 67-tetrahydrobenzo[b]thiophenementioning

confidence: 81%

“…As expected, the first oxidation potential for oligomers 143-146 is shifted cathodically with increasing chain length. The oxidation potentials of dodecamer 145 (Epd = 0.19 V vs Fc/Fc+) and hexadecamer 146 (Epa = 0.12V vs Fc/Fc+) are more negative than that of the structurally related poly(3-dodecyl-2,2'-bithiophene) (EFd = 0.3-0.35 V vs Fc/Fc+) [169]. This clearly indicates that longer oligomers exceed the average conjugated chain length of the parent polythiophenes which typically lie at 8-10 properly linked monomer units.…”

Section: -141mentioning

confidence: 99%

Sulfur‐Containing Oligomers

Bäuerle¹,

Becher²,

Lau³

et al. 1998

Electronic Materials: The Oligomer Approach

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Oligothiophene – immer länger? Synthese, Charakterisierung und rastertunnelmikroskopische Abbildung von homologen, isomerenreinen Oligo(alkylthiophenen)

Cited by 61 publications

References 31 publications

Iterative Binomial Synthesis of Monodisperse Polyfluorenes up to 64-mers and Their Chain-Length-Dependent Properties

Iterative Binomial Synthesis of Monodisperse Polyfluorenes up to 64-mers and Their Chain-Length-Dependent Properties

Oligothiophene Versus β‐Sheet Peptide: Synthesis and Self‐Assembly of an Organic Semiconductor‐Peptide Hybrid

Sulfur‐Containing Oligomers

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