Poly‐Onio‐Substituted Quinones as Strong Electron Acceptors

Weiß, Robert; Salomon, Norbert J.; Miess, Georg E.; Roth, Reinhard

doi:10.1002/anie.198609171

Cited by 33 publications

(6 citation statements)

References 4 publications

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“…Furthermore, such a process should not be very difficult, as Weiss et al have shown that onio substitution dramatically increases the electron affinity of a given substance. [14] To test this hypothesis, and knowing that ylide 2 a featuring the very basic tris(dimethylamino)phosphine is stable, [8] we prepared the phosphonio-substituted aldiminium salt 1 a and reduced it with potassium metal (Scheme 3). The reaction was carried out in tetrahydrofuran at À50 8C.…”

Section: Resultsmentioning

confidence: 99%

New Synthetic Routes to C‐Amino Phosphorus Ylides and their Subsequent Fragmentation into Carbenes and Phosphines

Conejero¹,

Song²,

Martín³

et al. 2006

Chemistry An Asian Journal

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Phosphonio-substituted aldiminium, iminium and imidazolidinium salts are readily prepared in excellent yields by addition of phosphines to Alder's dimer, or by treatment of the corresponding chloro iminium salt with the in situ generated phosphine/trimethylsilyl triflate adduct. A two-electron reduction, using either potassium metal or tetrakis(dimethylamino)ethylene, leads to the corresponding C-amino phosphorus ylides. When basic phosphine fragments are used, the ylides can be isolated; otherwise they spontaneously undergo a fragmentation into carbene and phosphine. Although the reduction/fragmentation sequence occurs under mild conditions, this method is limited to the preparation of transient carbenes, due to the non-availability of sterically hindered dications, and consequently of phosphorus ylides bearing bulky carbon substituents. To overcome this difficulty, a second novel route to phosphorus ylides has been developed: The addition, at low temperature, of 2,4-di-tert-butyl-ortho-quinone to readily available C-amino phosphaalkenes. Provided the phosphorus atom bears either an amino or tert-butyl group, a [4+1]-cycloaddition occurs, and the resulting ylides spontaneously undergo a fragmentation into a dioxaphospholane and a spectroscopically observed carbene.

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Section: Resultsmentioning

confidence: 99%

New Synthetic Routes to C‐Amino Phosphorus Ylides and their Subsequent Fragmentation into Carbenes and Phosphines

Conejero¹,

Song²,

Martín³

et al. 2006

Chemistry An Asian Journal

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“…This assumption is backed by ample literature evidence that, unlike easily reduced 4,4′-bipyridinium derivatives, 5 , 30 , 31 DMAP + -polysubstituted arenes and quinones undergo reductions at far more negative voltages and that these reductions are often irreversible in nature. 32 , 33 …”

Section: Resultsmentioning

confidence: 99%

“…It is important to note that these conclusions were reached under the assumption that the pyridinium groups themselves do not undergo reduction processes at these potentials. This assumption is backed by ample literature evidence that, unlike easily reduced 4,4′-bipyridinium derivatives, ,, DMAP + -polysubstituted arenes and quinones undergo reductions at far more negative voltages and that these reductions are often irreversible in nature. , …”

Section: Resultsmentioning

confidence: 99%

“…This assumption is backed by ample literature evidence that, unlike easily reduced 4,4′-bipyridinium derivatives, 5,30,31 DMAP +polysubstituted arenes and quinones undergo reductions at far more negative voltages and that these reductions are often irreversible in nature. 32,33 To further probe the validity of this assumption and investigate the electronic structure of the cationic PMDIs, DFT calculations (Figure 4) with the M06-2X functional at the 6-31G(d) level of theory were performed on the N,N′-dimethyl analogues of P, 1 + , and 2 2+ in the gas phase. Much like the solid-state structures obtained through single-crystal X-ray diffraction, the sterically demanding imide groups force the DMAP + units to twist at 52.5 and 55.8°dihedral angles to the PMDI benzene ring in 1 + and 2 2+ , respectively.…”

Section: ■ Results and Discussionmentioning

confidence: 99%

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Pyridinium-Functionalized Pyromellitic Diimides with Stabilized Radical Anion States

et al. 2018

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In this work, we report the stabilization of the reduced states of pyromellitic diimide by charge-balancing the imide radical anions with cationic pyridinium groups attached to the aromatic core. This structural modification is confirmed by single-crystal X-ray diffraction analysis. Characterization by (spectro)electrochemical experiments and computations reveal that the addition of cationic groups to an already electron-deficient ring system results in up to +0.57 V shifts in reduction potentials, largely as a consequence of charge screening and lowest unoccupied molecular orbital-lowering effects. This formal charge-balancing approach to stabilizing the reduced states of electron-deficient pyromellitic diimides will facilitate their incorporation into spin-based optoelectronic materials and devices.

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“…Avoiding the use of transition-metal catalysts is important because such metals can contaminate the resultant polymers as an insoluble residue that can adversely affect performance when the polymers are used in electronic devices. S N Ar reactions using thiolates, − aryloxides, − and pyridine derivatives − as nucleophiles have been used to fabricate functional small molecules and polymeric materials. However, the use of S N Ar reactions for modifying the main chain of conjugated polymers, again, remains rare. ,,− …”

Section: Introductionmentioning

confidence: 99%

Diversification of Conjugated Polymers via Postpolymerization Nucleophilic Aromatic Substitution Reactions with Sulfur-, Oxygen-, and Nitrogen-Based Nucleophiles

et al. 2021

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A postpolymerization nucleophilic aromatic substitution reaction is used as a strategy to efficiently diversify conjugated polymers. Conjugated polymers and small molecular models bearing tetrafluorophenyl and octafluorobiphenyl units are reacted with thiophenol derivatives, phenol derivatives, and carbazole in the presence of bases. Model reactions provide insights into the reactivity, numbers and patterns of substitution, structural features, and spectroscopic data. Thiophenol derivatives and carbazole achieve complete substitution of fluorine atoms in both the polymer and the model reactions, whereas phenol derivatives result in di-substitution in each arene ring with para-selectivity. The highly twisted and structurally rigid main chain structures are confirmed for a fully substituted arene motif in both the polymers and the models, resulting in the formation of syn- and anti-atropisomer or axial chirality and in the twisted intramolecular charge transfer character. The obtained polymers and models show unique optical and electrochemical properties, including phosphorescence at low temperatures in the case of the sulfur-containing materials.

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Poly‐Onio‐Substituted Quinones as Strong Electron Acceptors

Cited by 33 publications

References 4 publications

New Synthetic Routes to C‐Amino Phosphorus Ylides and their Subsequent Fragmentation into Carbenes and Phosphines

New Synthetic Routes to C‐Amino Phosphorus Ylides and their Subsequent Fragmentation into Carbenes and Phosphines

Pyridinium-Functionalized Pyromellitic Diimides with Stabilized Radical Anion States

Diversification of Conjugated Polymers via Postpolymerization Nucleophilic Aromatic Substitution Reactions with Sulfur-, Oxygen-, and Nitrogen-Based Nucleophiles

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