Fullerene Rotation Research Articles

Fullerene rotation dictated by benzene–fullerene interactions

The temperature-driven dynamics of Dy2ScN@C80 in the crystal was rigorously visualized with single crystal X-ray diffraction, indicating a surprising effect of benzene positions dictating fullerene rotation.

The hidden features of fullerene rotation in the crystal lattice

Variable-temperature single-crystal X-ray diffraction elaborated the phase transition in Sc3N@C70 crystals and allowed to distinguish hidden static disorder from dynamic disorder caused by thermal motion.

Fullerene in a Magnetic Field

The manuscript presents a trajectory method for describing the rotations of surface crystals such as fullerenes, nanotubes, and nanotori. This method does not require the implementation of successive rotations of the considered molecular structures around the axes of the selected basis. Therefore, it is free from the shortcomings of the approaches of Euler and Hamilton. On its basis, an efficient algorithm for calculating the motions of a magneto-susceptible fullerene in an alternating magnetic field has been developed. The nature of rotation of fullerenes in fields of various configurations has been studied.

ВРАЩЕНИЯ И ВИБРАЦИИ ФУЛЛЕРЕНОВ В МОЛЕКУЛЯРНОМ КОМПЛЕКСЕ C20@C80

The aim of this work is to apply classical mechanics to a description of the dynamic state of C20@C80 diamond complex. Endohedral rotations of fullerenes are of great interest due to the ability of the materials created on the basis of onion complexes to accumulate energy at rotational degrees of freedom. For such systems, a concept of temperature is not specified. In this paper, a closed description of the rotation of large molecules arranged in diamond shells is obtained in the framework of the classical approach. This description is used for C20@C80 diamond complex. Two different problems of molecular dynamics, distinguished by a fixing method for an outer shell of the considered bimolecular complex, are solved. In all the cases, the fullerene rotation frequency is calculated. Since a class of possible motions for a single carbon body (molecule) consists of rotations and translational displacements, the paper presents the equations determining each of these groups of motions. Dynamic equations for rotational motions of molecules are obtained employing the moment of momentum theorem for relative motions of the system near the fullerenes’ centers of mass. These equations specify the operation of the complex as a molecular pendulum. The equations of motion of the fullerenes’ centers of mass determine vibrations in the system, i.e. the operation of the complex as a molecular oscillator.

Effect of a charged particle propagating in C60 fullerite

The interaction of a charged particle and a rotating fullerene molecule in a fullerite crystal is investigated. The mathematical model was constructed and implemented for fullerene rotation frequencies up to 1014 Hz and velocities of an incident charged particle of the order of 103 m s−1. The study was carried out using the methods of classical molecular physics. The characteristics of the motion of the C60 fullerene molecule were determined using the laws of classical mechanics, Euler's approach, and a step-by-step numerical method of a high order of accuracy. The influence of the action of a charged particle on the nature of the motion of a rotating fullerene was analyzed according to the results of the performed numerical experiments.

Forced rotation of fullerenes in an electromagnetic fields

A mathematical model of molecular dynamics is presented, which allows one to study the behavior of molecular crystals both in electromagnetic fields and in the absence of fields. This model is universal and affordable, and also does not require high computing power. The fullerene-based materials continue to exhibit unique properties, and the applicability of such materials is steadily increasing. A study of fullerite in the solid phase with charged fullerenes was carried out, characteristic states of the substance were obtained, and their potential properties were analyzed. The potential use of the material is also described taking into account the properties obtained.

(Invited) Structures and Properties of Saturn-like Complexes Composed of Oligothiophene Macrocycle with Methano[60]Fullerene and [70]Fullerene

π-Expanded oligothienylene macrocycle with a large inner cavity incorporates fullerenes such as methano[60]fullerene (C61H2) and [70]fullerene (C70) inside to form Saturn-like complexes.[1] Although the oligothiophene macrocycle weakly interacts with fullerenes in solution, it forms stable Saturn-like fullerene complexes in the solid state. X-ray analysis of the Saturn-like complexes exhibited short contacts between the sulfur atoms of the oligothiophene macrocycle and fullerene carbons, which hinder the rotation of fullerenes. As a result, the non-covalent interaction between the oligothiophene macrocycle and fullerenes was employed in crystal structure determination of fullerenes. UV–vis–NIR spectra of the Saturn-like complexes showed weak donor–acceptor interaction between the oligothiophene macrocycle and fullerenes. [1] M. Iyoda, H. Shimizu, S. Aoyagi, H. Okada, B. Zhou, Y. Matsuo, Can. J. Chem. 95 (2017) 315-319.

Structures and properties of Saturn-like complexes composed of oligothiophene macrocycle with methano[60]fullerene and [70]fullerene

π-Expanded oligothienylene macrocycle with a large inner cavity incorporates fullerenes such as methano[60]fullerene (C61H2) and [70]fullerene (C70) inside to form Saturn-like complexes. Although the oligothiophene macrocycle weakly interacts with fullerenes in solution, it forms stable Saturn-like fullerene complexes in the solid state. X-ray analysis of the Saturn-like complexes exhibited short contacts between the sulfur atoms of the oligothiophene macrocycle and fullerene carbons, which hinder the rotation of fullerenes. As a result, the non-covalent interaction between the oligothiophene macrocycle and fullerenes was employed in crystal structure determination of fullerenes. UV–vis–NIR spectra of the Saturn-like complexes showed weak donor–acceptor interaction between the oligothiophene macrocycle and fullerenes.

Lattice dynamics of a rotor-stator molecular crystal: Fullerene-cubaneC60⋅C8H8

The dynamics of fullerene-cubane $({\text{C}}_{60}\ensuremath{\cdot}{\text{C}}_{8}{\text{H}}_{8})$ cocrystal is studied combining experimental [x-ray diffuse scattering, quasielastic and inelastic neutron scattering (INS)] and simulation (molecular dynamics) investigations. Neutron scattering gives direct evidence of the free rotation of fullerenes and of the libration of cubanes in the high-temperature phase, validating the ``rotor-stator'' description of this molecular system. X-ray diffuse scattering shows that orientational disorder survives the order/disorder transition in the low-temperature phase, although the loss of fullerene isotropic rotational diffusion is featured by the appearance of a 2.2 meV mode in the INS spectra. The coupling between INS and simulations allows identifying a degeneracy lift of the cubane librations in the low temperature phase, which is used as a tool for probing the environment of cubane in this phase and for getting further insights into the phase transition mechanism.

Light-induced EPR study of charge transfer in poly(3-hexylthiophene)/fullerene bulk heterojunction

The first results of the light-induced EPR study of magnetic, relaxation, and dynamic parameters of charge carriers background photoinduced by optical photons (1.7-3.4 eV) in poly(3-hexylthiophene)/fullerene bulk heterojunctions are described. All magnetic resonance parameters for positively charged polaron and negatively charged fullerene ion-radical in radical pairs photoinduced in the composite were determined separately by the steady-state microwave saturation method. Paramagnetic susceptibility of charge carriers reflects their activation dynamics and exchange interaction. A decay of long-living radical pairs depends on the spatial distance between photoinduced charge carriers. The one-dimensional polaron diffusion along the polymer chain and fullerene rotation near the main molecular axis was shown to follow activation Elliot hopping model and to be governed by photon energy. The difference in activation energies of the charge carriers' dynamics and in their dependence on the exciting photon energy proves their noninteracting character in the polymer/fullerene composite. Main magnetic, relaxation and dynamics parameters of charge carriers are governed by the photon energy band due to inhomogeneity of distribution of polymer and fullerene domains in the composite.

Light-induced EPR spectroscopy of charge carriers photoinduced in polymer/fullerene bulk heterojunctions

Composites of conjugated polymers with fullerenes are perspective materials for polymer photovoltaics. Light-induced EPR (LEPR) study of magnetic, relaxation, and dynamic parameters of polaron-fullerene radical pairs photoinduced in fullerene-modified poly(3-alkylthiophenes) is described. Weak interaction between positively charged polaron and negatively charged fullerene ion radical in the pairs allowed to determine separately all their magnetic, relaxation, and dynamics parameters. Paramagnetic susceptibility of charge carriers reflects their activation dynamics and spin exchange in the composite. Decay of long-living polaron and fullerene anion radical depends on a spatial distance between them and the energy of exciting photons. One-dimensional polaron diffusion along the polymer chain and fullerene rotation near its own main molecular axis were shown to follow the activation Elliot hopping model and to be governed by photon energy. The deviation in activation energies for dynamics of charge carriers and the difference in their dependence on the exciting photon energy prove the noninteracting character of charge carriers photoinduced in the polymer/fullerene composite. The dependence of the main magnetic, relaxation, and dynamics parameters of charge carriers on the phonon energy was ascribed to inhomogeneous distribution of polymer and fullerene domains in bulk heterojunctions. This inhomogeneity decreases by the annealing of the composite.

Orientational Ordering and Low-Temperature Libration in the Rotor−Stator Cocrystals of Fullerenes and Cubane

Cocrystals of cubane and fullerenes, C60-cubane and C70-cubane, show distinct rotational ordering transitions. We studied the corresponding structural changes with temperature-dependent X-ray diffraction and the thermodynamics of the phase transitions with adiabatic microcalorimetry and differential scanning calorimetry. C60-cubane has one phase transition around 130 K from a high-temperature fcc phase with freely rotating C60 to a low-temperature orthorombic phase in which the fullerene rotation is frozen. The corresponding enthalpy change is approximately 1170 J/mol, and the entropy change is 9.6 J/(mol K). C70-cubane has two phase transitions. Around 380 K, the high-temperature fcc phase with freely rotating C70 transforms into a bct phase in which the C70 rotates uniaxially around an axis that precesses around the c direction with a full opening angle of 40 degree. Around 170 K, the uniaxial rotation also freezes out, with an accompanying structural transition to monoclinic and enthalpy and entropy changes of 620 J/mol and 8.7 J/(mol K), respectively. The low-temperature specific heat was analyzed in terms of the Debye-Einstein model to estimate the librational energies of the fullerenes and Debye temperatures. We found very similar values for the two cocrystals, approximately Elib = 2.2 meV and TDebye = 23 K. For reference, we also measured the specific heats of pure C60 and C70 and found Elib = 2.96 meV and TDebye = 32 K for C60 and Elib = 1.9 meV and TDebye = 20 K for C70.

Dynamics of charge carriers photoinduced in poly(3-dodecylthiophene)/fullerene bulk heterojunction

Magnetic and dynamics properties of mobile polarons and fullerene anion-radicals photoinduced by laser beam in the poly(3-dodecylthiophene)/fullerene bulk heterojunction were studied. The number of these charge carriers was found to decrease with the growth in the photon energy. Monotonic temperature dependence for main electron relaxation parameters was obtained. The 1D polaron diffusion along the polymer chain and the fullerene rotation was shown to follow activation Elliot hopping model and to govern by the photon energy. The deviation in activation energies for polaron and anion-radical motion and the difference in their dependence on the laser irradiation photon energy prove a non-interacting character of these charge carriers photoinduced in the polymer/fullerene bulk heterojunction.

Structural study of C60 and C70 cubane

AbstractFullerenes and cubane (C8H8) form new high‐symmetry heteromolecular crystals and C60–cubane and C70–cubane are the first members of this family. We present the results of a detailed structural study in a wide temperature range, from 100 K to 470 K. The structure of these compounds is based on the well‐known face centered cubic (fcc) C60 lattice. In the highest symmetry case freely rotating fullerenes occupy the fcc lattice sites, and cubanes fill the octahedral voids. We found various phase transitions on lowering the temperature. As expected, the free rotation of fullerenes becomes hindered and orientational ordering appears. The orientational transition temperature is exceptionally low, which can be explained by the combination of the high symmetry environment of fullerenes, the perfect match of convex fullerene and concave cubane molecular surfaces and the significantly expanded fullerene lattice. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

Electronic properties of peapods: effects of fullerene rotation and different types oftube

Effects of encapsulated fullerene rotation on peapod electronic properties are studied by usingSlater–Koster tight-binding calculations. We found that the encapsulated fullerenes can rotatefreely in the space of a (10, 10) tube at room temperature, and the rotation of fullerenes will affectC60@(10,10) peapod electronic properties significantly; generally, orientational disorder will remove thesharp features of the average density of states (DOS). However, the rotation of fullerenescannot induce a metal–insulator transition. Electronic properties of peapods formedby fullerenes and different types of single-walled carbon nanotube (SWNT) arestudied too. Percentage calculations suggest that, unlike the multicarrier metallicC60@(10,10) peapod,the C60@(17,0) peapod is a semiconductor, and the effects of the encapsulated fullerenes on tube valencebands and conduction bands are asymmetrical.

Lattice Dynamics of Fullerenes Probed by Organometallic Intercalates

The 14.4 keV nuclear γ-ray resonance in 57Fe has been used as a probe of the hyperfine interactions and lattice dynamics of the bisferrocene (Fc) intercalates of C60 and C70. Over the temperature range 90 ≤ T ≤ 350 K the isomer shift is a smooth function of T and is very similar for neat Fc and the two intercalates. In contrast, the T-dependence of the quadrupole hyperfine interaction undergoes a marked change in slope at ∼300 K in C60Fc2, but not in C70Fc2. A similar discontinuity at ∼300 K is observed in the temperature dependence of the recoil-free fraction in C60Fc2, but not in C70Fc2. These observations can be related to the known phase change and onset of fullerene rotation in the former (as contrasted to the latter) and are supported by DSC measurements in the interval 240 ≤ T ≤ 380 K for both intercalates.

The transition from the ordered to the merohedral disordered phase in oxygenated solid C 60

C 60 powder, pellets and single crystals were oxygenated at 0.11 kbar and then studied with MAS 13C NMR, DSC and XRD. In agreement with reports by other authors, powder samples exhibited minor NMR resonances, indicative of blocking of fullerene rotation by interstitial oxygen, the distribution of which had yet to attain the equilibrium state. Also, as reported by others, DSC showed two endothermic peaks near 260 K, and both, we found, corresponded to a discontinuous change in the lattice parameter. The peak on the low-temperature side moved up in temperature with elapsed time. Pellets, in which presumably oxygen diffused easily, displayed only one peak but shifted in the same manner. Single crystals, in contrast, had only the higher-temperature “immobile” peak. We suggest that the shifting endotherm originates from the transition of oxygen-intercalated C 60 to a merohedral disordered phase, in which the rotation of fullerene molecules is partially impeded by oxygen. A phenomenological model is proposed for this transition.

Rotational excitation of fast fullerenes at grazing scattering by a solid surface

The scattering of fast fullerenes (with the initial energy higher than 1 keV/atom) by a solid surface under grazing incidence is considered. The frictional force, associated with the position dependent inelastic stopping power, decreases with the distance from the surface. The resultant torque acting on fullerene does not equal to zero and, therefore, causes the fullerene rotation. The rotational energy of a scattered fullerene is calculated. Estimates show that the fragmentation of a fullerene can occur via rotational excitation.