π-Dimers and π-Stacks in Solution and in Conducting Polymers

Miller, Larry L.; Mann, Kent R.

doi:10.1021/ar9600446

Cited by 352 publications

(273 citation statements)

References 43 publications

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“…The equilibrium distance turns out to be around 0.3 Å larger in the periodic system, although it exhibits a slightly stronger binding. This is in agreement with experimental data showing that ⌬H d is enhanced by the length of the chain, 20 a trend related to a "dilution" of the Coulombic repulsion as the ratio between charge and oligomer size decreases. 22 At the same time, however, the increase in length at a given oxidation state would diminish the ratio between unpaired electrons available to -bonding and thiophene rings.…”

Section: Resultssupporting

confidence: 92%

“…Since the early 1990s electrochemical and spectroscopic evidences were gathered indicating that oxidized oligothiophenes reversibly associate in solution. [19][20][21] In a recent study, 22 we have outlined how this association is driven by three contributions: the attractive -interactions, the Coulombic repulsion, and the solvent effects. In the case of oligothiophene cations dimers, combination of half-filled highest occupied molecular orbitals ͑HOMOs͒ forms occupied bonding and empty antibonding orbitals, resulting in an interaction of covalent character, different in nature to the one arising in neutral dimers, of dispersive origin.…”

Section: Introductionmentioning

confidence: 99%

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Stacking of oligo- and polythiophene cations in solution: Surface tension and dielectric saturation

Scherlis

Fattebert

Marzari

2006

The Journal of Chemical Physics

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The stacking of positively charged ͑or doped͒ terthiophene oligomers and quaterthiophene polymers in solution is investigated applying a recently developed unified electrostatic and cavitation model for first-principles calculations in a continuum solvent. The thermodynamic and structural patterns of the dimerization are explored in different solvents, and the distinctive roles of polarity and surface tension are characterized and analyzed. Interestingly, we discover a saturation in the stabilization effect of the dielectric screening that takes place at rather small values of ⑀ 0 . Moreover, we address the interactions in trimers of terthiophene cations, with the aim of generalizing the results obtained for the dimers to the case of higher-order stacks and nanoaggregates.

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Section: Resultssupporting

confidence: 92%

Section: Introductionmentioning

confidence: 99%

Stacking of oligo- and polythiophene cations in solution: Surface tension and dielectric saturation

Scherlis

Fattebert

Marzari

2006

The Journal of Chemical Physics

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“…Numerous experimental and theoretical studies already explored the electronic structure of oxidized thiophenes at a fundamental level, but mixed-valence approaches are comparatively rare. [6][7][8][9][10][11][12][13][14] In a purely computational study, Lacroix and coworkers arrived at the conclusion that oligothiophene monocations may be described as organic mixed-valence species. 15 Indeed, the oneelectron oxidized or one-electron reduced forms of several oligo-p-phenylene and oligo-p-phenylene vinylene systems could be described well as organic mixed-valence compounds in various experimental studies, [16][17][18][19][20][21][22][23][24][25] but until now there has been comparatively little conceptually analogous work on thiophene systems.…”

Section: Introductionmentioning

confidence: 99%

Charge Delocalization in a Homologous Series of α,α′-Bis(dianisylamino)-Substituted Thiophene Monocations

et al. 2012

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A homologous series of three molecules containing thiophene, bithiophene and terthiophene bridges between two redox-active tertiary amino-groups was synthesized and explored. Charge-delocalization in the one-electron oxidized forms of these molecules was investigated by a combination of cyclic voltammetry, near-infrared optical absorption spectroscopy, and EPR spectroscopy. All three cation radicals can be described as organic mixed-valence species, and for all of them the experimental data is consistent with strong delocalization of the unpaired electron. Depending on what model is used for 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 2 analysis of the optical absorption data, estimates for the electronic coupling matrix element (H AB ) range from ∼5000 cm -1 to ∼7000 cm -1 for the shortest member of the homologous series. According to optical absorption and EPR spectroscopy even the terthiophene radical appears to belong either to Robin-Day class III or to a category of radicals commonly denominated as borderline class II / class III systems. The finding of such a large extent of charge delocalization over up to three adjacent thiophene units is remarkable.

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“…The construction of complex and multifunctional p-architecture is difficult because of the poor directionality of p,p-interactions (8)(9)(10)(11)(12)(13)(14)(15)(16)(17)(18). Apart from a central role in oligonucleotide chemistry and biology (18), cofacial p-stack architecture contributes very little to electron transfer in biological (1-3) and synthetic (4-7) photosystems, not to speak of the structure of biological or synthetic ion channels or pores (19).…”

mentioning

confidence: 99%

Photoproduction of Proton Gradients with π-Stacked Fluorophore Scaffolds in Lipid Bilayers

Bhosale

Sisson

Talukdar

et al. 2006

Science

419

372

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Rigid p -octiphenyl rods were used to create helical tetrameric π-stacks of blue, red-fluorescent naphthalene diimides that can span lipid bilayer membranes. In lipid vesicles containing quinone as electron acceptors and surrounded by ethylenediaminetetraacetic acid as hole acceptors, transmembrane proton gradients arose through quinone reduction upon excitation with visible light. Quantitative ultrafast and relatively long-lived charge separation was confirmed as the origin of photosynthetic activity by femtosecond fluorescence and transient absorption spectroscopy. Supramolecular self-organization was essential in that photoactivity was lost upon rod shortening (from p -octiphenyl to biphenyl) and chromophore expansion (from naphthalene diimide to perylene diimide). Ligand intercalation transformed the photoactive scaffolds into ion channels.

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π-Dimers and π-Stacks in Solution and in Conducting Polymers

Cited by 352 publications

References 43 publications

Stacking of oligo- and polythiophene cations in solution: Surface tension and dielectric saturation

Stacking of oligo- and polythiophene cations in solution: Surface tension and dielectric saturation

Charge Delocalization in a Homologous Series of α,α′-Bis(dianisylamino)-Substituted Thiophene Monocations

Photoproduction of Proton Gradients with π-Stacked Fluorophore Scaffolds in Lipid Bilayers

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