Doping of C60 with tertiary amines: TDAE, DBU, DBN. A comparative study

Klos, H.; Rystau, I.; Schütz, Wilhelm; Gotschy, B.; Skiebe, Andreas; Hirsch, Andreas

doi:10.1016/0009-2614(94)00550-8

Cited by 29 publications

(19 citation statements)

References 13 publications

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“…Importantly, the high stability of the radical ion pairs in [4] •+ ⊂[C60] •− is highlighted upon comparison with previous studies into the interaction of C60 and simple organic amine donors that reported significant air and moisture sensitivity 116 of the C60 •− generated with t½ = 10 -30 mins. 133,134,136 After three days the complex solution returned to its original green colour (Figure 5a) and the Vis-NIR absorption spectrum predominantly resembled that of the 'neutral' Green Box and C60 fullerene species, i.e. reforming [4] δ+ ⊂[C60] δ− (Figure S4.10-4.11).…”

Section: Nitrobenzenementioning

confidence: 98%

“…This remarkable durability of the radical ions in solution prompted a more detailed kinetic study by Vis-NIR absorption, EPR and NMR spectroscopies. A time course measurement of the electronic absorption band associated with [PDI] •+ at λabs = 890 nm of a 1:5 host:guest stoichiometric mixture revealed fast SET followed by a slow decrease in concentration of this species over seven hours, 123,133,134 giving a PDI radical cation half-life of t½ > 600 minutes with radical ions still apparent in the NIR spectrum after two days (Figure S7.1). 135 Under the same conditions the time dependence of the EPR spectrum revealed similar kinetic behaviour for C60 •− (Figures S6.3, S7.2).…”

Section: Nitrobenzenementioning

confidence: 99%

“…137 Over the same time course, 1 H NMR spectroscopy revealed a gradual sharpening of Green Box proton resonances (Figure S2.9) with 13 C NMR (Figure S2.10) and MALDI-TOF mass spectra (Figure S3.3) also confirming the presence of pristine C60 fullerene whilst no new signals appeared in the EPR spectrum. Furthermore, TLC analysis of the mixture indicated only the regeneration of starting materials (via back electron transfer) so that, unlike with simple organic amine donors, 116,125,134 follow up chemical reactions do not occur. The superior SET behaviour of Green Box with C60 can be related to contrasting chemical structures; it has been shown that sterically hindered tertiary amines, 134 such as those present in the bis-pyrrolidine PDI panels of 4, produce a more persistent spin density in solution than secondary or less bulky amines 116,125,134 for which new covalent bond forming reaction pathways can compete.…”

Section: Nitrobenzenementioning

confidence: 99%

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The Green Box: An Electronically Versatile Perylene Diimide Macrocyclic Host for Fullerenes

et al. 2019

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The powerful electron accepting ability of fullerenes makes them ubiquitous components in biomimetic donor-acceptor systems that model the intermolecular electron transfer processes of Nature's photosynthetic centre. Exploiting perylene diimides (PDIs) as components in cyclic host systems for the noncovalent recognition of fullerenes is unprecedented, in part because archetypal PDIs are also electron deficient, making dyad assembly formation electronically unfavourable. To address this, we report the strategic design and synthesis of a novel large, macrocyclic receptor comprised of two covalently strapped electron-rich bis-pyrrolidine PDI panels, nicknamed the "Green Box" due to its colour. Through the principle of electronic complementarity, the Green Box exhibits strong recognition of pristine fullerenes (C60/70), with the non-covalent ground and excited state interactions that occur upon fullerene guest encapsulation characterised by a range of techniques including electronic absorption, fluorescence emission, NMR and time-resolved EPR spectroscopies, cyclic voltammetry and mass spectrometry. Whilst relatively low polarity solvents result in partial charge transfer in the host donor-guest acceptor complex, increasing the polarity of the solvent medium facilitates rare, thermally allowed full electron transfer from Green Box to fullerene in the ground state. Both species in the ensuing charge separated radical ion paired complex are spectroscopically characterised, with thermodynamic reversibility and significant kinetic stability also demonstrated. Importantly, the Green Box represents a seminal type of C60/70 host where electron-rich PDI motifs are utilised as recognition motifs for fullerenes, facilitating novel intermolecular, solvent tuneable ground state electronic communication with these guests. The ability to switch between extremes of the charge transfer energy continuum is without precedent in synthetic fullerene-based dyads.

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Section: Nitrobenzenementioning

confidence: 98%

Section: Nitrobenzenementioning

confidence: 99%

Section: Nitrobenzenementioning

confidence: 99%

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The Green Box: An Electronically Versatile Perylene Diimide Macrocyclic Host for Fullerenes

et al. 2019

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“…However, very few new compounds have been found to show similar behaviour, and until very recently TDAE-C6o remained the comp ound with the highest Tc. For example TDAE-C70 and many different TDAEdoped C6o derivatives show no evidence for a ferromagnetic (FM) state down to 4K -which is also true when TDAE is substit uted with other electron donors [7] -and although there have been some reports of possible ferromagnetism at higher temp eratures [8], up until quite recently such unidentified ferromagnetic organic comp ounds (UFOs) have so far failed the reproducibility test. The current record thus stands at 20K, which was set very recently at our laboratory and is for cobaltocene-3-aminophenyl-methano-[6o]fullerene [9], whose properties are currently being intensively investigated.…”

Section: Magnetism In Fullerenesmentioning

confidence: 99%

Molecular Magnetism with Fullerene Building Blocks: the race is on for High T

Mihailovic¹

1997

Europhysics news

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Ferromagnetism in organic materials with only p electrons is a relatively new phenomenon having been discovered only a few years ago. Recent discoveries of fullerene charge-transfer compounds with Curie temperatures beyond the exotic experimental domain of dilution refrigerators, together with progress in our understanding of the magnetically ordered state, opens the field to discoveries of potentially useful organic ferromagnets.

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“…16 The electron transfer reactions of cyclic amines such as diazabicyclo(5.3.0)non-5-ene (DBN) and 1,8diazabicyclo(5.4.0)undec-7-ene (DBU) with C 60 have also been examined. 17,18 DBU was found to react with C 60 by electron transfer to form the radical ions C 60 À and DBU + , followed by formation of a diamagnetic adduct with and optical absorbance in the near infrared region. 17 Recently addition of DBU was found to lead to increases in the electrical conductivity of [6,6] a Electronics Materials and New Energy Laboratory, Mitsubishi Chemical dithiophene (ITIC).…”

Section: Introductionmentioning

confidence: 99%