Theoretical calculations of the structure and UV–vis absorption spectra of hydrated C60 fullerene

Abstract

A combined Monte Carlo simulation with semiempirical quantum mechanics calculations has been performed to investigate the structure of hydrated fullerene (C 60 HyFn) and the influence of hydration on its UV-vis spectra. The statistical information of the C 60 fullerene aqueous solution (C 60 FAS) is obtained from NPT ensemble including one C 60 fullerene immerses in 898 water molecules. To obtain an efficient ensemble average, the auto-correlation function of the energy has been calculated. The analyzed center-of-mass pair-wise radial distribution function indicates that, on average, there are 65 and 151 water molecules around the first and second hydration shells, respectively, of a single C 60 molecule. To calculate the average UV-vis transition energies of C 60 HyFn, only the statistically uncorrelated configurations are used in the quantum mechanical calculations (INDO/CIS). These involve hundreds of supramolecular structures containing one C 60 fullerene surrounded by the first hydration shell. The calculated average transitions at 268 and 350 nm are in very good agreement with the experimental prediction.

Towards better understanding of C60organosols

“…The numerous and sometimes conflicting results of experimental 5,14,[16][17][18][19][20][21][22][23][24][25][43][44][45][46][47][48][49] and theoretical [73][74][75][76][77][78][79] investigations demand such a comparison. Indeed, the theoretical calculations often predict strong interaction between C 60 and water (as a recent example, the work by Choi et al 77 may be proposed), which may be considered as a type of expressed hydration, whereas the coagulation data indicate the hydrophobic nature of the fullerene hydrosols.…”

Inclusion Complexation of Praziquantel and -Cyclodextrin, Combined Molecular Mechanic and Monte Carlo Simulation

“…Of course, the hydrogen bonding formation will depend on the type of interaction potential used in the simulation. 26 The first shell is formed by ∼2 water molecules around PZQ molecule, which it presents preferential hydrogen bond interactions between water and oxygen in the PZQ molecule. The second shell is formed by ∼6 water molecules around PZQ molecules.…”

Synthesis of Mono-Dispersed Nano-Scale Fullerene (C<SUB>60</SUB>) Crystals

“…260 and 338 cm, the peak at 530 nm showed a hypsochromic shift, a slight shorter-wavelength shift (from 531 to 525 nm), depending on the increase in the pH, indicating that the solid clusters developed more log stacking of toluene and a donoracceptor complex between C 60 and toluene when increasing the pH. 24 Thus, the difference between the bathochromic shift at ca. 260 and 338 nm and the hypsochromic shift at 530 nm suggests that the crystallinity of nanoscale crystal and the toluene composition in the nC 60 structure increased when increasing the pH of the water used.…”

“…The use of solvents involves changing the C 60 lattice in the crystal structure, resulting in different optical and electronic spectra. [21][22][23][24][25] However, until now, controlling the nano-scale crystallinity of C 60 crystals has been considered very difficult. Accordingly, this study varied the pH of the medium under conditions of supersaturation in an attempt to control the crystallinity of the product.…”