Thienopyrazine‐Based Low‐Bandgap Poly(heteroaryleneethynylene)s for Photovoltaic Devices

Ashraf, Raja Shahid; Shahid, Munazzaa; Klemm, Elisabeth; Al‐Ibrahim, Maher; Sensfuß, Steffi

doi:10.1002/marc.200600314

Cited by 160 publications

(94 citation statements)

References 33 publications

(63 reference statements)

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“…Such E p,a values afford an approximate estimation of the HOMO energy levels for the five molecules (also reported in Table 3) by use of Equation (1): [17,18] E HOMO ½eV % À1eðE p,a ½V vs: Fc þ jFc þ 4:8 ½V Fc þ jFc vs: zeroÞ ð1Þ ultimately based on the absolute value for the normal hydrogen electrode (NHE) critically assessed in a fundamental review paper. [19] More significant, albeit moderate, appears the positive shift of the first reduction peak potentials, E p,c , with increasing n a .…”

Section: Electrochemical Properties Of T'xmentioning

confidence: 99%

Towards Molecular Design Rationalization in Branched Multi‐Thiophene Semiconductors: The 2‐Thienyl‐Persubstituted α‐Oligothiophenes

Benincori

Bonometti

Angelis

et al. 2010

Chemistry A European J

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The introduction of branching in multi-thiophene semiconductors, although granting the required solubility for processing, results in an increased molecular fluxionality and a higher level of distortion, thus hampering pi conjugation. Accordingly, branched oligothiophenes require rationalization of their structure-reactivity relationships for target-oriented design and optimization of the synthetic effort. Our current research on spiderlike oligothiophenes affords deep insight into the subject, and introduces new, easily accessible molecules with attractive functional properties. In particular, a regular series, T'X(Y), of five new multi-thiophene systems, T'5(3), T'8(4), T'11(5), T'14(6), and T'17(7), constituted by five, eight, 11, 14, and 17 thiophene units, respectively, their longest alpha-conjugated chain consisting of tri-, tetra-, penta-, hexa-, and heptathiophene moieties, respectively, has been synthesized and fully characterized from the structural, spectroscopic, and electrochemical point of view. The electronic properties of the monomers and their electropolymerization ability are discussed and rationalized as a function of their molecular structure, particularly in comparison with the series of 5-(2,2'-dithiophene)yl-persubstituted alpha-oligothiophenes (TX(Y)) previously reported by us. These oligothiophenes are easily accessible materials, with promising properties for applications as active layers in multifunctional organic devices including solar cells.

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Section: Electrochemical Properties Of T'xmentioning

confidence: 99%

Towards Molecular Design Rationalization in Branched Multi‐Thiophene Semiconductors: The 2‐Thienyl‐Persubstituted α‐Oligothiophenes

Benincori

Bonometti

Angelis

et al. 2010

Chemistry A European J

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“…From the first oxidation and reduction peak potentials, values of HOMO and LUMO levels can be estimated by the following equations [72,73] ultimately based on the absolute value for the normal hydrogen electrode (NHE) critically assessed in a fundamental review paper: [74] E HOMO (eV) » -1e ´ [ (E p,a (V vs Fc + |Fc) + 4.8 (V Fc + |Fc vs zero)]…”

Section: Electrochemical Homo and Lumo Levels And Gapsmentioning

confidence: 99%

Ternary thiophene–X–thiophene semiconductor building blocks (X=fluorene, carbazole, phenothiazine): Modulating electronic properties and electropolymerization ability by tuning the X core

Tacca

Pò

Caldararo

et al. 2011

Electrochimica Acta

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To achieve rationalization criteria for target-oriented molecular design of Th-X-Th (Th = thiophene) semiconductor building blocks, we have carried out an extensive investigation on the effects of the X core (X = fluorene, carbazole or phenothiazine) on the electronic properties and polymerization ability of Th-X-Th monomers and on the electronic and structural properties of the corresponding periodic conducting polymers -(Th-X-Th) n -, obtained by electropolymerization and, for

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“…Although it is impossible to obtain a precise discussion due to the presence of irreversible redox waves, as shown in Table 3, the HOMOLUMO gaps of the three molecules, estimated from the onsets of the oxidation and the reduction peaks, indicated the similarity between 1 and 5 (¦E CV : 2.82 eV for 1, 2.81 eV for 5, and 3.41 eV for 6, respectively). 10 These results indicated that electrochemical and optical properties of the C 70 fragment 1 are also largely affected by the indenopyrene 5 skeleton rather than benzo [e]pyrene 6 skeleton.…”

Section: ¹1mentioning

confidence: 87%

Synthesis of a C₇₀ Fragment Buckybowl C₂₈H₁₄ from a C₆₀ Fragment Sumanene

et al. 2017

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A C 70 fragment (1) (C 28 H 14 ) was synthesized by conversion of a C 60 fragment sumanene, via ring expansion and annulation in 3 steps, the key step being the WagnerMeerwein rearrangement of a five-membered ring to a six-membered one. Both theoretical and experimental investigations exhibited the shallower bowl structure of 1, resulting in the lower bowl inversion barrier than sumanene. It was also revealed that the indenopyrene skeleton largely contributed to the physical properties of 1. Bowl-shaped π-conjugated aromatic hydrocarbons, corresponding to the fragments of fullerenes (buckybowls), have been attracting widespread interest owing to their unique chemical and physical properties.1 Buckybowls, which possess the fragment skeleton of C 60 , such as corannulene and sumanene, have been extensively studied and various unique properties have been reported. 2,3 In contrast, buckybowls bearing C 70 fragment have not drawn much attention and only few examples have been reported to date. 4 The feature of C 70 is that the presence of additional ten carbons, which connect the two C 60 -like hemispheres and provide the shallower curved structure partially than in C 60 skeleton. A simple and effective method to achieve the formation of the fragment skeleton of C 70 is the conversion of the fused five-membered ring in the fragment structure of C 60 to the fused six-membered ring, which realizes the bowl-depth change from deeper to shallower.Here we show the synthesis of a new buckybowl C 28 H 14 (1) (Figure 1), corresponding to a 40% fragment of C 70 from the C 60 fragment sumanene (2) via ring expansion and annulation, in which WagnerMeerwein rearrangement of a five-membered ring to a six-membered one was the key step.The synthetic plan from sumanene 2 to 1 is shown in Scheme 1 according to Bavin's report on the transformation from the fluorene skeleton to the phenanthrene one via Wagner Meerwein rearrangement (Scheme 1).5 Generation of benzylic carbanion by the addition of n-BuLi (150 mol %) to 2 in THF at ¹80°C, followed by the addition of aryl or heteroaryl aldehydes (150 mol %) quantitatively afforded the precursors 3a3c for the rearrangement reaction (Table 1). The WagnerMeerwein rearrangement was carried out by the reaction of 3a3c with stoichiometric p-TsOH in toluene under reflux condition, giving the benzopyrene derivative 4a4c in good yields. X-ray singlecrystal analysis of 4b confirmed its shallower curved structure

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Thienopyrazine‐Based Low‐Bandgap Poly(heteroaryleneethynylene)s for Photovoltaic Devices

Cited by 160 publications

References 33 publications

Towards Molecular Design Rationalization in Branched Multi‐Thiophene Semiconductors: The 2‐Thienyl‐Persubstituted α‐Oligothiophenes

Towards Molecular Design Rationalization in Branched Multi‐Thiophene Semiconductors: The 2‐Thienyl‐Persubstituted α‐Oligothiophenes

Ternary thiophene–X–thiophene semiconductor building blocks (X=fluorene, carbazole, phenothiazine): Modulating electronic properties and electropolymerization ability by tuning the X core

Synthesis of a C₇₀ Fragment Buckybowl C₂₈H₁₄ from a C₆₀ Fragment Sumanene

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Thienopyrazine‐Based Low‐Bandgap Poly(heteroaryleneethynylene)s for Photovoltaic Devices

Cited by 160 publications

References 33 publications

Towards Molecular Design Rationalization in Branched Multi‐Thiophene Semiconductors: The 2‐Thienyl‐Persubstituted α‐Oligothiophenes

Towards Molecular Design Rationalization in Branched Multi‐Thiophene Semiconductors: The 2‐Thienyl‐Persubstituted α‐Oligothiophenes

Ternary thiophene–X–thiophene semiconductor building blocks (X=fluorene, carbazole, phenothiazine): Modulating electronic properties and electropolymerization ability by tuning the X core

Synthesis of a C70 Fragment Buckybowl C28H14 from a C60 Fragment Sumanene

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Synthesis of a C₇₀ Fragment Buckybowl C₂₈H₁₄ from a C₆₀ Fragment Sumanene