Synthesis and properties of pyrazolino[60]fullerene-donor systems

Espíldora, Eva; Delgado, Juan Luis; Cruz, Pilar de la; Hoz, Antonio de la; López-Arza, Vicente; Langa, Fernando

doi:10.1016/s0040-4020(02)00552-5

Cited by 46 publications

(37 citation statements)

References 32 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The cycloreversion reaction of these compounds seems to take place efficiently only when charged species, induced either by Lewis acid metals or ESI conditions, are involved. In contrast, diaryl substituted 2-pyrazolinofullerenes are thermally stable compounds and the retro-cycloaddition process does not take place even under microwave irradiation [24,40].…”

Section: Resultsmentioning

confidence: 99%

Mass Spectrometry Studies of the Retro-Cycloaddition Reaction of Pyrrolidino and 2-Pyrazolinofullerene Derivatives Under Negative ESI Conditions

Delgado

Filippone

Martín‐Domenech

et al. 2011

J. Am. Soc. Mass Spectrom.

Self Cite

View full text Add to dashboard Cite

Substituted pyrrolidino-and 3-alkyl-2-pyrazolinofullerenes ionize under ESI and MALDI mass spectrometry conditions and negative mode of detection undergoing mass spectral fragmentations, which can be easily correlated with the reported results for the thermal and electrochemical retro-cycloaddition reactions of these compounds. 2-Pyrazolinofullerenes lead directly to a [60] fullerene product ion formed through a retro-cycloaddition process regardless of the substituents attached at the carbon and nitrogen atoms of the heterocyclic ring. These results are different from whose reported for the thermal and electrochemical processes. In contrast, pyrrolidinofullerenes undergo different fragmentative reactions depending upon the substituents (hydrogen, alkyl, or acyl) attached at the nitrogen atom of the heterocyclic ring leading eventually to the pristine C 60 in the last step of the fragmentation pathway.

show abstract

Section: Resultsmentioning

confidence: 99%

Mass Spectrometry Studies of the Retro-Cycloaddition Reaction of Pyrrolidino and 2-Pyrazolinofullerene Derivatives Under Negative ESI Conditions

Delgado

Filippone

Martín‐Domenech

et al. 2011

J. Am. Soc. Mass Spectrom.

Self Cite

View full text Add to dashboard Cite

show abstract

“…[12][13][14] Extending these studies, we here focus our investigations on the design and directed (i.e., stereoselective) synthesis of C 3 -symmetrical (chiral) tribenzotriquinacene stators, which are crucial yet unexplored components of a nanoratchet system featuring unidirectional rotation. We also present the first results on the self-assembly of chiral stator (7) with fullerene-type rotors, in conjunction with molecular dynamics (MD) simulations, demonstrating the asymmetry of the rotational energy profile for a rotor like R. [10] Results and Discussion Synthesis of the chiral receptor (7) We herein report the synthesis of the first chiral and enantiopure tribenzotriquinacene receptor 7 for C 60 fullerene possessing C 3 point group symmetry (Scheme 1). The C 3 symmetry of 7 is induced by tert-butyl substituents placed at appropriate positions of the tribenzotriquinacene moiety.…”

Section: Introductionmentioning

confidence: 94%

“…b) Alternative ratchet design in which the gearwheel is set in a molding shaped to admit rotation in one direction only. c) Nanoratchet design comprising the C 3 -symmetrical (chiral) tribenzotriquinacene stator (7, spheres point to the position of bulky substituents, for example, tert-butyl groups), and a (putative) C 60 fullerene-based rotor R [10] (Figure 7). Hydrogen atoms are omitted for clarity.…”

Section: Introductionmentioning

confidence: 99%

Tribenzotriquinacene Receptors for C₆₀ Fullerene Rotors: Towards C₃ Symmetrical Chiral Stators for Unidirectionally Operating Nanoratchets

Bredenkötter

Grzywa

Alaghemandi

et al. 2014

Chemistry A European J

View full text Add to dashboard Cite

The synthesis of a stereochemically pure concave tribenzotriquinacene receptor (7) for C60 fullerene, possessing C3 point group symmetry, by threefold condensation of C2 -symmetric 1,2-diketone synthons (5) and a hexaaminotribenzotriquinacene core (6) is described. The chiral diketone was synthesized in a five-step reaction sequence starting from C2h -symmetric 2,6-di-tert-butylanthracene. The highly diastereo-discriminating Diels-Alder reaction of 2,6-di-tert-butylanthracene with fumaric acid di(-)menthyl ester, catalyzed by aluminium chloride, is the relevant stereochemistry introducing step. The structure of the fullerene receptor was verified by (1)H and (13)C NMR spectroscopy, mass spectrometry and single crystal X-ray diffraction. VCD and ECD spectra were recorded, which were corroborated by ab initio DFT calculations, establishing the chiral nature of 7 with about 99.7 % ee, based on the ee (99.9 %) of the chiral synthon (1). The absolute configuration of 7 could thus be established as all-S [(2S,7S,16S,21S,30S,35S)-(7)]. Spectroscopic titration experiments reveal that the host forms 1:1 complexes with either pure fullerene (C60) or fullerene derivatives, such as rotor 1'-(4-nitrophenyl)-3'-(4-N,N-dimethylaminophenyl)-pyrazolino[4',5':1,2][60]fullerene (R). The complex stability constants of the complexes dissolved in CHCl3/CS2 (1:1 vol. %) are K([C60 ⊂7]) = 319(±156) M(-1) and K([R⊂7]) = 110(±50) M(-1). With molecular dynamics simulations using a first-principles parameterized force field the asymmetry of the rotational potential for [R⊂7] was shown, demonstrating the potential suitability of receptor 7 to act as a stator in a unidirectionally operating nanoratchet.

show abstract

“…Four of them (E [60]fullerene derivatives, the first reduction potentials (E 1 red ) are analogous to that of pristine C 60 and shifted to more positive values relative to other fullerene derivatives due to the ÀI effect of the pyrazoline ring. [53,54] On the oxidation side, an irreversible one-electron wave was observed at around + 0.44 V (F-3 PV-F) and + 0.35 V (F-5 PV-F), while these waves appear at + 0.34 V and + 0.31 V in F-3 PV and F-5 PV, respectively. Similarly, bishydrazones 6 and 12 show the same oxidation around + 0.37 V. These values can be assigned to the oxidation of the OPV moiety, in agreement with previous reports.…”

Section: Electrochemistrymentioning

confidence: 99%

“…This result is in agreement with those observed in other fulleropyrazoline derivates with electrondonor or electron-withdrawing susbtituents. [54] The absorption spectra of the oligophenylenevinylene (OPV) model compounds 3 PV and 5 PV are depicted in Figure 3. They exhibit the characteristic p-p* absorption with maxima at 409 and 447 nm, respectively.…”

Section: Photophysical Propertiesmentioning

confidence: 99%

Pyrazolino[60]fullerene–Oligophenylenevinylene Dumbbell‐Shaped Arrays: Synthesis, Electrochemistry, Photophysics, and Self‐Assembly on Surfaces

Langa

Gómez‐Escalonilla

Rueff

et al. 2005

Chemistry A European J

Self Cite

View full text Add to dashboard Cite

Symmetrically substituted oligophenylenevinylene (OPV) derivatives bearing terminal p-nitrophenylhydrazone groups have been prepared and used for the synthesis of dumbbell-shaped bis(pyrazolino[60]fullerene)-OPV systems. In these triad arrays, the OPV-type fluorescence is dramatically quenched as a consequence of ultrafast OPV-->C60 singlet energy transfer. In its turn the fullerene singlet state is quenched by pyrazoline-->C60 electron transfer, in line with the behavior of the corresponding reference fullerene molecule. The occurrence of electron transfer in the multicomponent arrays is evidenced by recovery of fullerene fluorescence at 77 K in CH2Cl2 and in toluene at 298 K. Under these conditions the OPV-->C60 energy transfer is unaffected. The rate of this process turns out to be higher for the OPV trimer than for the corresponding pentameric OPV arrays, in agreement with energy-transfer theory expectations. Scanning tunneling microscopy (STM) and scanning force microscopy (SFM) revealed that the bis(pyrazolino[60]fullerene)-OPV can self-assemble into ordered layered crystalline architectures on the basal plane of highly oriented pyrolitic graphite.

show abstract

Synthesis and properties of pyrazolino[60]fullerene-donor systems

Cited by 46 publications

References 32 publications

Mass Spectrometry Studies of the Retro-Cycloaddition Reaction of Pyrrolidino and 2-Pyrazolinofullerene Derivatives Under Negative ESI Conditions

Mass Spectrometry Studies of the Retro-Cycloaddition Reaction of Pyrrolidino and 2-Pyrazolinofullerene Derivatives Under Negative ESI Conditions

Tribenzotriquinacene Receptors for C₆₀ Fullerene Rotors: Towards C₃ Symmetrical Chiral Stators for Unidirectionally Operating Nanoratchets

Pyrazolino[60]fullerene–Oligophenylenevinylene Dumbbell‐Shaped Arrays: Synthesis, Electrochemistry, Photophysics, and Self‐Assembly on Surfaces

Contact Info

Product

Resources

About

Synthesis and properties of pyrazolino[60]fullerene-donor systems

Cited by 46 publications

References 32 publications

Mass Spectrometry Studies of the Retro-Cycloaddition Reaction of Pyrrolidino and 2-Pyrazolinofullerene Derivatives Under Negative ESI Conditions

Mass Spectrometry Studies of the Retro-Cycloaddition Reaction of Pyrrolidino and 2-Pyrazolinofullerene Derivatives Under Negative ESI Conditions

Tribenzotriquinacene Receptors for C60 Fullerene Rotors: Towards C3 Symmetrical Chiral Stators for Unidirectionally Operating Nanoratchets

Pyrazolino[60]fullerene–Oligophenylenevinylene Dumbbell‐Shaped Arrays: Synthesis, Electrochemistry, Photophysics, and Self‐Assembly on Surfaces

Contact Info

Product

Resources

About

Tribenzotriquinacene Receptors for C₆₀ Fullerene Rotors: Towards C₃ Symmetrical Chiral Stators for Unidirectionally Operating Nanoratchets