An unpaired electron-based hole-transporting molecule: Triarylamine-combined nitroxide radicals

Kurata, Takeshi; Koshika, Kenichiroh; Kato, Fumiaki; Kido, Junji; Nishide, Hiroyuki

doi:10.1039/b703790b

Cited by 33 publications

(17 citation statements)

References 25 publications

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“…According to Creutz and Taube, the most common MV compounds are represented by the general formula [M a n −BL−M b n +1 ], in which BL refers to an organic bridge and M a and M b are usually redox‐active inorganic or organometallic centers . Transition‐metal complexes that are decorated with additional redox‐active units represent one type of promising photoelectric materials that display intriguing electrochemical and photophysical properties and are potentially useful for applications in molecular electronics, information storage, charge transportation, light scavenging, and solar cells . In most cases, the BL backbones in these MV systems are readily oxidizable organic bridge cores, such as unsaturated sp/sp 2 ‐carbon‐based chains (oligoyne, oligoene) or fused aromatic rings (heterocycles, oligoacene) .…”

Section: Introductionmentioning

confidence: 99%

Diphenylamine‐Substituted Osmanaphthalyne Complexes: Structural, Bonding, and Redox Properties of Unusual Donor–Bridge–Acceptor Systems

Zhang

Jin

et al. 2018

Chemistry A European J

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Diarylamine‐substituted osmanaphthalyne complexes that feature two redox centers linked by the rigid skeleton of the metallacycle (C^C+), specifically, [OsCl2(PPh3)2{(C^C+)NAr2}][BF4−] (Ar=Ph (1 a), p‐MeOPh (1 b)) and their open‐ring precursors [OsHCl2(PPh3)2{(≡C−C(PPh3+)=CHPh)NR2}][BF4−] (Ar=Ph (2 a), p‐MeOPh (2 b)), were successfully synthesized and characterized by 1H, 13C, and 31P NMR spectroscopy, ESI‐MS, and elemental analysis. The solid‐state molecular structures of complexes 1 a and 2 a were ascertained by single‐crystal X‐ray diffraction. The Os≡C bond length in both complexes 1 a and 2 a fell within the range reported for similar osmanaphthalynes and osmium carbyne complexes, respectively. The structural parameters determined for complex 1 a, which were successfully reproduced by theoretical calculations, point to a π‐delocalized metallacycle structure. The purple color of compounds 1 a and b was explained by the diarylamine→Os(metallacycle) charge‐transfer absorption in the visible region. The neutral, one‐electron‐oxidized and one‐electron‐reduced states of compounds 1 a, b, and a reference complex that lacked the diarylamine substituent, [OsCl2(PPh3)2{(C^C+)}][BF4−] (1′), were investigated by cyclic and square‐wave voltammetry, UV/Vis/NIR spectroelectrochemistry, and DFT calculations. The spin density in singly oxidized complexes [1 a]+ and [1 b]+ predominantly resided on the aminyl segment, with osmium involvement controlled by the diphenylamine substitution. Spin density in stable, singly‐reduced [1′]− was distributed mainly over the osmanaphthalyne metallacycle.

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Section: Introductionmentioning

confidence: 99%

Diphenylamine‐Substituted Osmanaphthalyne Complexes: Structural, Bonding, and Redox Properties of Unusual Donor–Bridge–Acceptor Systems

Zhang

Jin

et al. 2018

Chemistry A European J

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“…[9] Since this pioneering work, the Nakahara group has reported the synthesis of a polymeric TEMPO radical derivative, poly(2,2,6,6-tetramethylpiperidinyloxy methacrylate) (PTMA), for an organic radical battery. [10] The research group of Nishide extended this work toward applications, such as radical batteries as cathode active materials, [11] organic light-emitting diodes as holeinjection layers, [12] and memory as p-type redox active materials.…”

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confidence: 99%

Nitronyl Nitroxide Radicals as Organic Memory Elements with Both n‐ and p‐Type Properties

et al. 2011

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“…Our recent examples include triarylamine-based high-spin oligo-and poly(cationic radical)s, [36][37][38][39][40][41] polymer gels of p-phenylenediamine-based cationic radicals, 42 as well as their applications to organic devices. 43,44 During the course of this series of studies, we have shown an RT ground state multiplet polyradical using a poly[1,2,(4)-phenylenevinyleneanisylaminium] hyperbranched structure, prepared by a tedious multistep synthesis of the AB2-type monomer, followed by self-polycondensation and terminal protection. 45 This triarylamine-based cationic polyradical displayed a remarkable thermal stability even at 70 1C.…”

Section: Introductionmentioning

confidence: 99%

Two-dimensionally extended organic high-spin poly(aminium cationic radical)s and their magnetic force microscopic images

Michinobu

Inui

Nishide

2010

Polym J

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Purely organic high-spin poly(aminium cationic radical)s of two-dimensionally extended soluble aromatic polyamines P1 and P2 were prepared by the palladium-catalyzed polycondensation of two multifunctional monomers, followed by chemical or electrochemical oxidations. The chemical structures of the precursor polyamines were fully characterized by 1 H-and 13 C nuclear magnetic resonance (NMR), infrared and MALDI-TOF mass spectra (MS). The aminium radical sites of N,N,N¢,N¢-tetraaryl-pphenylenediamines were connected through the m-phenylene ferromagnetic coupler, which satisfies the non-Kekulé -type molecular design. Oxidation of radical sites was facilitated by electron-donating methoxy substituents. The first oxidation potential (E o ¢(1)) of P2 with methoxy substituents, evaluated from the cyclic voltammograms in CH 2 Cl 2 , was 0.69 V (vs Ag/Ag + ), whereas the E o ¢(1) of P1 without electron-donating substituents was 0.78 V. This result was further verified by spectroelectrochemistry measurements. The electrochemically oxidized P2 displayed a more intense low-energy band at ca. 800 nm ascribed to aminium cationic radicals and bications. Chemical oxidation of P1 and P2 with NOPF 6 solubilized with 18-crown-6 in CH 2 Cl 2 gave the corresponding poly(aminium cationic radical)s. The high-spin ground states were confirmed by the temperature dependence of forbidden electron spin resonance (ESR) transition peak intensities, and the average spin quantum number (S) determined by the magnetic curves reached 8.4/2 at low temperatures. Remarkably, when a small amount of trifluoroacetic acid was added, the half-life of polyradicals reached ca. 1 week at room temperature (RT). This result prompted us to observe the single polymer-based molecular and magnetic images by atomic force microscopy and magnetic force microscopy, respectively. The precursor polyamine P1 showed globular-shaped polymer particles with an average vertical distance of 1.43 nm. After chemical oxidation, the vertical distance of P1 definitely decreased, reflecting the improved p-type character of the nitrogen atoms. Moreover, the detection of weak MFM images supported the presence of magnetic spins in the single polymers.

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An unpaired electron-based hole-transporting molecule: Triarylamine-combined nitroxide radicals

Abstract: A durable nitroxide radical combined with a triarylamine moiety exhibited a hole-drift mobility of 6 x 10(-3) cm(2) V(-1) s(-1), to which the aminophenyl nitroxide structure contributed.

Cited by 33 publications

References 25 publications

Diphenylamine‐Substituted Osmanaphthalyne Complexes: Structural, Bonding, and Redox Properties of Unusual Donor–Bridge–Acceptor Systems

Diphenylamine‐Substituted Osmanaphthalyne Complexes: Structural, Bonding, and Redox Properties of Unusual Donor–Bridge–Acceptor Systems

Nitronyl Nitroxide Radicals as Organic Memory Elements with Both n‐ and p‐Type Properties

Two-dimensionally extended organic high-spin poly(aminium cationic radical)s and their magnetic force microscopic images

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