Search results for "fullerene"

Diffusion-Driven Formation of MoS2 Nanotube Bundles Containing MoS2 Nanopods

2011

MoS2 nanotube bundles, along with embedded nested fullerenes, were formed in a gas-phase reaction of molybdenum carbonyl and H2S gas with the assistance of I2. The amorphous Mo-S-I precursor particles obtained by quenching a modified metal organic chemical vapor deposition (MOCVD) reaction in a large temperature gradient were annealed at elevated temperature in an inert atmosphere. Under the influence of the iodine, the amorphous precursor formed a surface film with an enhanced mobility of the molybdenum and sulfur components. Point defects within the MoS2 layers, combined with the enhanced surface diffusion, lead to a scrolling of the inherently unstable MoS2 lamellae. The role of the reac…

Fullerene-ionic-liquid conjugates: a new class of hybrid materials with unprecedented properties.

2015

A modular approach has been followed for the synthesis of a series of fullerene-ionic-liquid (IL) hybrids in which the number of IL moieties (two or twelve), anion, and cation have been varied. The combination of C60 and IL give rise to new unique properties in the conjugates such as solubility in water, which was higher than 800 mg mL(-1) in several cases. In addition, one of the C60 -IL hybrids has been employed for the immobilization of palladium nanoparticles through ion exchange followed by reduction with sodium borohydride. Surprisingly, during the reduction several carbon nanostructures were formed that comprised nano-onions and nanocages with few-layer graphene sidewalls, which have…

Photoinduced Modifications of the Structure and Microhardness of Fullerite C60

2004

The wavelength dependence, temperature limits, time and depth evolution of the photoinduced hardening of C60 crystals in air have been investigated by microindentation and dislocation mobility methods. Two photopolymerized phases, which differ in the hardness and thermal stability, are found to appear. We suggest that formation of fullerene dimers (ie. C120) in pristine fullerite and growth of C120O phase in oxygenated fullerite via [2+2] photoaddition reaction is responsible for it. It has been found from depth distribution data of the hardness that the C120O phase is located in oxygen-contaminated subsurface layer of 0.8–1 μm and appears under illumination at 290–330 K.

Cyclotriveratrylene-Containing Porphyrins

2016

International audience; The C-3-symmetric cyclotriveratrylene (CTV) was covalently bonded via click chemistry to 1, 2, 3, and 6 zinc(II) porphyrin units to various host for C-60. The binding constants, Ka, were measured from the quenching of the porphyrin fluorescence by C-60. These constants vary between 400 and 4000 M-1 and are considered weak. Computer modeling demonstrated that the zinc(II) porphyrin units, [Zn], exhibit a strong tendency to occupy the CTV cavity, hence blocking the access for C-60 to land on this site. Instead, the pincer of the type [Zn]-[Zn] and in one case [Zn]-CTV, were found to be the most probable geometry to promote host-guest associations in these systems.

Polymer solar cells based on diphenylmethanofullerenes with reduced sidechain length

2011

Diphenylmethanofullerenes (DPMs) show interesting properties as acceptors in polymer bulk heterojunction solar cells due to the high open circuit voltages they generate compared to their energy levels. Here we investigate the effect of reducing the alkane sidechain length of the DPMs from C12 to C6 in the properties of the solar cell. This change leads to an increase in the electron mobility, thus allowing for a lower fullerene content, which in turn results in an increase in the short circuit current and, finally, in an increase in the efficiency of the device (from 2.3 to 2.6%) due to the higher concentration of the more absorbing polymer in the film. Atomic force microscopy images and ex…

Fullerene polymers: synthesis and properties

2007

DLPNO-CCSD(T) scaled methods for the accurate treatment of large supramolecular complexes

2017

In this work, we present scaled variants of the DLPNO-CCSD(T) method, dubbed as (LS)DLPNO-CCSD(T) and (NS)DLPNO-CCSD(T), to obtain accurate interaction energies in supramolecular complexes governed by noncovalent interactions. The novel scaled schemes are based on the linear combination of the DLPNO-CCSD(T) correlation energies calculated with the standard (LoosePNO and NormalPNO) and modified (Loose2PNO and Normal2PNO) DLPNO-CCSD(T) accuracy levels. The scaled DLPNO-CCSD(T) variants provide nearly TightPNO accuracy, which is essential for the quantification of weak noncovalent interactions, with a noticeable saving in computational cost. Importantly, the accuracy of the proposed schemes is…

Mimicking photosynthesis: covalent [60]fullerene-based donor–acceptor ensembles

2004

Abstract Within the context of exploring photophysical properties of [60]fullerene-based donor–acceptor ensembles, we highlight in this contribution an approach towards the synthesis of a novel series of donor-bridge-acceptor, C 60 –wire– ex TTF , ensembles that incorporate p -phenylenevinylene oligomers, in which the conjugation length has been systematically increased, as bridges that connect π-extended tetrathiafulvalenes (exTTF) (electron donor) with [60]fullerene (electron acceptor). This molecular design allows probing the effects of distance and rate, at which electron transfer processes occur, as well as the molecular-wire behavior of the oligo-PPV fragments.

DFT study of the interaction free energy of p–p complexes of fullerenes with buckybowls and viologen dimers

2011

We present a theoretical investigation, by means of DFT protocols, of the complexation thermodynamics of (i) complexes of C70 and C60 fullerenes with bowl-shaped hexabenzocoronene derivatives and (ii) complexes of C60 with viologen dimers. The recent functionals of the M06 family, accounting for p-p interactions to a good level of approximation, have been used to calculate the interaction free energies. For the former complexes, the good agreement between the calculated results and the experimental data confirms the reliability of the protocol used. On these grounds, we then checked the stability of a series of complexes of C60 with some viologen dimers, 1BPnBP1 (n = 6-9), where two N-methy…

Cyclodextrin-[60]fullerene conjugates: synthesis, characterization, and electrochemical behavior

2006

Three different functionalized β-cyclodextrins (β-CDs) bearing the C60 moiety linked covalently have been prepared in good yields by reaction between the parent β-CD and [60]fullerene via 1,3-dipolar cycloaddition. These compounds have been fully spectroscopically characterized and their electrochemical behavior has been investigated. Surprisingly, the electrochemical properties of the C60 cage remain unaltered even after chemical functionalization, making these systems very appealing as supramolecular hosts for electron-transfer processes.