On a specific state of C60 fullerene in N-methyl-2-pyrrolidone solution: Mass spectrometric study

Abstract

A solution of fullerene C 60 in N-methylpyrrolidone (NMP) presents a suitable system for tunable size. However, a mechanism of interaction of a polar NMP solvent with the fullerene molecules is still elusive. Herein, we present the laser desorption/ionization mass spectra (LDI MS) of the precipitates produced from C 60 /NMP solutions of different age in comparison with the typical spectra of C 60 crystallized from toluene and benzene. The distinctive characteristics of the C 60 /NMP mass spectra were identified and carefully examined. The number of characteristic peaks and their relative intensities in the spectra strongly depends on the age of the initial C 60 /NMP solutions. This effect was attributed to the specific C 60-NMP interactions in the solution, namely to the formation of the chargetransfer complexes of C 60 with NMP molecules followed by the fullerene cluster formation. The results of additional measurements carried out by means of Small-angle X-ray scattering (SAXS), Nuclear magnetic resonance (NMR), UV-Vis adsorption spectroscopy together with the Density functional theory (DFT) calculations were in accord with the proposed hypothesis.

Liquid Systems with Fullerenes in Organic Solvents and Aqueous Media

“…Besides the time-dependent solvatochromic effect, the studies of the C 60 /NMP/water and C 70 /NMP/toluene systems [54,55] also revealed the drastic appearance of the solvatochromism when adding second solvent to the initial C 60 /NMP system, the absorption spectrum of which had not been ultimately smoothed out yet [56]. It was shown that the both effects emerge owing to the formation of donor-acceptor bonds [50,57], which, according to the results of theoretical calculations, are formed between oxygen atoms in the NMP molecule and carbon atoms of fullerene [58,59]. The formation of donor-acceptor bonds is responsible for the aggregate stabilization and changes the fullerene properties.…”

Application of the Consonance Solvent Concept for Accurate Prediction of Buckminster Solubility in 180 Net Solvents using COSMO-RS Approach

“…Unfortunately, in reports providing the values of solubility there are not sufficient information about solid phase present in the equilibrium with the saturated solutions. Although no direct clues about C60 solvates can be inferred from solubility measurements this aspect was not overlooked and attracted serious attention by many investigators [10][11][12][13][14][15][16][17][64][65][66][67][68]. For example, the dissolution properties of C60 in aromatic solvents were studied using the thermos-analytical approach [10,12] and many solid solvates were identified.…”

“…It is also worth mentioning that the reference solvent method cannot help in the cases if solid states in equilibrium with saturated solutions comprise solvates. Since, there is a vast gross of evidences [10][11][12][13][14]16,17,[64][65][66]68] that Buckminster can interact with many solvents, it is quite clear that reference solubility cannot be used neither for serious improvement of predicted solubility data nor for treating cases of unknown fusion characteristics.…”

“…Unfortunately, low solubility of C60 in many organic solvents [7] stands for the major cost of the production from soot [8], since extraction by organic solvents is the first step for obtaining fullerenes-rich fractions further separated using HPLC [9]. Moreover, strong tendency of precipitation in the form of solvates [10][11][12][13][14][15][16][17] makes it difficult to preserve purity of the solid. This is why modeling of C60 solubility attracted so much attention and resulted in a variety of theoretical approaches, among which the best predications come so far from non-linear modeling via machine learning [18].…”

Investigations of the Kinetics of Cluster Growth in Fullerene C60 Solutions

“…Investigations of the effect of solvent polarity (using binary mixtures) reveals a certain transitional value of the dielectric permittivity of a solvent [26]. A subclass of these systems can be distinguished for the nitrogen-containing solvents such as N-methyl-pyrrolidone (NMP) [27][28][29][30] and pyridine [8]. The formation of donor-acceptor type complexes between fullerene and solvent molecules takes place [30][31][32], and a peculiar transition from a molecular to a stable colloidal solution, accompanied by the color change, can be observed.…”