Synthesis, Characterization and Theoretical Calculation of the Fulleropyrrolidines Containing Triphenylamine (original) (raw)
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Carbon, 2006
Fulleropyrrolidine and pyrrolidine derivatives were studied using X-ray photoemission spectroscopy in order to determine the effects of the C 60 -cage on the pyrrolidine nitrogen, as well as the influence of further derivatisation. Charge transfer from the carbon pyrrolidine ring to the C 60 -cages is observed and this charge redistribution influences not only the carbon atoms but also the nitrogen. The major influence of different functionalization groups on the pyrrolidine nitrogen is whether or not they lead to quaternisation while no differences could be detected for different groups (methyl group or alkyl chain) producing one or the other configuration. However, the type of counter ion is important for the stability of the pyrrolidinium nitrogen: demethylated nitrogen, always found to be present in iodide counter balanced compounds, disappears in compounds counter balanced with BF À 4 anion.
Journal of Materials Chemistry, 2002
Fullerene derivatives A-3PV and B-3PV in which an oligophenylenevinylene trimeric subunit (3PV) is attached to C 60 through, respectively, a pyrrolidine or a pyrazoline ring have been prepared. The electrochemical and excited-state properties of the multicomponent arrays A-3PV and B-3PV have been investigated in solution using the related oligophenylenevinylene derivative 3PV, fullerenopyrrolidine A and fullerenopyrazoline B as reference compounds. In A-3PV quantitative OPV A C 60 photoinduced singlet-singlet energy transfer has been observed. Population of the lowest fullerene singlet excited state is followed by nearly quantitative intersystem crossing to the lowest fullerene triplet excited state in CH 2 Cl 2 and toluene, whereas OPV A C 60 electron transfer is able to compete significantly in the more polar solvent benzonitrile. In the case of B-3PV, the excited-state properties are more complex due to the electron donating ability of the pyrazoline ring. As observed for A-3PV, quantitative OPV A C 60 photoinduced singlet-singlet energy transfer occurs in B-3PV. However, in this case, the population of the lowest fullerene singlet excited state is followed by an efficient electron transfer from the pyrazoline ring in CH 2 Cl 2 and benzonitrile. In B-3PV, studies of the dependence of photoinduced processes on solvent polarity, addition of acid, and temperature also reveal that this compound can be considered as a fullerene-based molecular switch, the switchable parameters being the photoinduced processes. Finally, A-3PV and B-3PV have been tested as active materials in photovoltaic devices and the differences of light to energy conversion efficiencies found for the two compounds have been rationalised on the basis of their photophysical properties.
Bulletin of the Chemical Society of Japan, 2007
Photoinduced intramolecular events of the newly synthesized fullerene-triphenylamine-fullerene (C 60-TPA-C 60) triad, in which the TPA entity was substituted with an electron-donating CH 3 O-group to increase electron-donating ability, were investigated in relation to a C 60-TPA dyad. The molecular orbital calculations showed that the radical cation is located on the TPA entity, whereas the radical anion is located on two C 60 entities in the radical ion pair. The fluorescence intensity of the singlet excited state of C 60 was efficiently quenched by the attached TPA moiety in polar solvents. The quenching pathway involves a charge-separation process from the TPA to the singlet excited state C 60. The lifetimes of the radical ion-pairs for C 60-TPA-C 60 evaluated from nanosecond transient absorption measurements were found to be 600 and 454 ns in benzonitrile and dimethylformamide, respectively. These lifetimes of radical ion-pairs of C 60-TPA-C 60 are longer than those of the C 60-TPA dyad, which reflects the effect of the second C 60 moiety in stabilizing the radical ion-pairs.
PLOS ONE
Since the early nineties, countless publications have been devoted to the study of possible uses of [60] fullerene (C 60) and its derivatives in the fields of materials and nano-biomedical sciences. However, in spite of the importance of conformers notably from the pharmacological point of view, the cis/trans isomerization of C 60 mono-adducts has been rarely seldom investigated. Here we present the results of DFT calculations of the structural, vibrational and NMR properties of both cis and trans isomers of fulleropyrrolidine mono-adduct obtained by photo-addition of glycine methyl ester to C 60. Taken together, our results have shown that the cis isomer is more stable than the trans one. For the cis conformation, the simulated vibrational spectrum shows a more intense peak at 1298 cm-1. While 13 C spectra revealed no significant differences between the two isomers as compared to experimental results, the calculated 1 H chemical shifts show a significant difference between the two conformers in both the gas phase and in solution. The trans isomer presents a proton at 5.86 ppm, which is more deshielded than the proton of the cis conformer (5.24 ppm).
International Journal of Photoenergy, 2001
A fullerene derivative in which two oligophenylenevinylene (OPV) groups are attached to C 60 through a pyrrolidine ring has been prepared and photophysical studies in CH 2 Cl 2 solution show that photoinduced energy transfer from the OPV moieties to C 60 occurs, and not electron transfer. On passing to a more polar solvent such as benzonitrile, again no evidence of electron transfer is found. the expected signals. Interestingly, the signals corresponding to some of the protons of the pyrrolidine ring and those of the phenyl group directly attached to it Vol. 3
Spectroscopic Analyses of Modified Fulleropyrrolidine Derivatives
The Open Spectroscopy Journal, 2015
Fullerene (C 60) is enhanced with pyrrolidine group to produce fulleropyrrolidine which is considered as one of the most important derivatives of fullerene. Fulleropyrrolidine is further modified in order to enhance its solubility which in turn could enhance its biological applications. Accordingly this work is dedicated to modify fulleropyrrolidine carbodithioic acid as NO 2 group introduced at meta position. Quantitative structure-activity relationship models (QSAR) was utilized to evaluate the biological activates of the investigated compounds through some descriptors. Later on chalcogenide could be subtitled in order to form three derivative groups. The QSAR descriptors were compared with the QSAR of the parent compound. Results indicate that, NO 2 group enhances the biological activity.
Theoretical investigation on two different mechanisms of fulleropyrrolidine formation
Theoretical Chemistry Accounts, 2016
AM1 level, and finally DFT on geometries optimized at DFT level were considered. At DFT level, GGA (PBE), hybrid (PBE0) and meta-GGA (M06-2X) were used, with a 6-31+G(d) basis set. We proved that the release of NH 3 and the ring formation step in the first mechanism require a higher energy barrier compared to the second mechanism reaction steps like tautomerization and H 2 O departure. Thus, we can conclude that the second mechanism involving in a first step the azomethine ylide formation is more favorable than the first mechanism. The interest in using in a first step a semiempirical determination of reaction paths is highlighted, and the choice of the exchange-correlation functional is discussed.
Physical Chemistry Chemical Physics, 2006
Pyrazolino[60]fullerene covalently-linked to ferrocene and N,N-dimethylaniline groups has been prepared and studied using time-resolved spectroscopic methods. The fluorescence quenching of the C 60 moiety indicates that charge-separation takes place via the singlet excited state of the C 60 moiety in both polar and non-polar solvents. The charge-separated state, in which an electron is localized on the C 60 sphere and a hole is located on the whole donor moieties of ferrocene, pyrazole, and N,N-dimethylaniline groups, has been confirmed by nanosecond transient spectra in the visible and near-IR spectral region. The lifetimes of the radical ion-pairs are as long as 30-50 ns in both polar and non-polar solvents.
Structural and electronic properties of pyrrolidine-functionalized [60] fullerenes
We have investigated energetic, geometric, electronic, and field emission properties of three recently synthesized fulleropyrrolidines based on the density functional theory method B3LYP/6-31G(d). Fulleropyrrolidines show higher conductivity, and solubility in water, and smaller work function in comparison with the pristine C 60 fullerene. The functionalization of C 60 with different pyrrolidines containing -NH 2 , NO, or NO 2 groups transforms it to an n-type semiconductor. The functionalization can also dramatically enhance the electrophilicity of the C 60 about 23-37%. Moreover, it should be mentioned that the work function is mainly influenced by the pyrrolidine containing -NO 2 group whereas the conductivity is largely affected by the one containing -NH 2 functionality.
The Journal of Physical Chemistry A, 2006
Photoinduced intramolecular processes in a tricomponent molecule C 60 (>(CN) 2-DPAF), consisting of an electron-accepting methano[60]fullerene moiety (C 60 >) covalently bound to an electron-donating diphenylaminofluorene (DPAF) unit via a bridging dicyanoethylenyl group [(CN) 2 ], were investigated in comparison with (CN) 2-DPAF. On the basis of the molecular orbital calculations, the lowest charge-separated state of C 60 (>(CN) 2-DPAF) is suggested to be C 60 •-(>(CN) 2-DPAF •+) with the negative charge localized on the fullerene cage, while the upper state is C 60 (>(CN) 2 •-DPAF •+). The excited-state events of C 60 (>(CN) 2-DPAF) were monitored by both time-resolved emission and nanosecond transient absorption techniques. In both nonpolar and polar solvents, the excited charge-transfer state decayed mainly through initial energytransfer process to the C 60 moiety yielding the corresponding 1 C 60 *, from which charge separation took place leading to the formation of C 60 •-(>(CN) 2-DPAF •+) in a fast rate and high efficiency. In addition, multistep charge separation from C 60 (>(CN) 2 •-DPAF •+) to C 60 •-(>(CN) 2-DPAF •+) may be possible with the excitation of charge-transfer band. The lifetimes of C 60 •-(>(CN) 2-DPAF •+) are longer than the previously reported methano[60]fullerene-diphenylaminofluorene C 60 (>(CdO)-DPAF) with the C 60 and DPAF moieties linked by a methanoketo group. These findings suggest an important role of dicyanoethylenyl group as an electron mediating bridge in C 60 (>(CN) 2-DPAF).