Fullerene

About: Fullerene is a research topic. Over the lifetime, 12723 publications have been published within this topic receiving 359173 citations.

Metalloporphyrin hosts for supramolecular chemistry of fullerenes

Abstract: This paper is a tutorial review of the host–guest chemistry of fullerenes and metalloporphyrin. Among various host molecules for fullerenes, cyclic hosts composed of metalloporphyrin moieties possess one of the highest affinities toward fullerenes, which can be widely tuned simply by changing the central metal ions of the porphyrin moieties. Inclusion of fullerenes occurs not only by van der Waals interactions but also, in some cases, via π-electronic charge-transfer from the host metalloporphyrin moieties to the guest fullerenes. Fullerenes such as C120, upon inclusion with cyclic metalloporphyrin dimers, show an oscillatory motion within the host cavity, whose frequency reflects the solvation/desolvation dynamics of the fullerenes. A molecularly engineered metalloporphyrin host with a self-assembling capability allows a guest-directed formation of a supramolecular peapod, where included fullerenes, as peas, are aligned along the self-assembled metalloporphyrin nanotube, as a pod. Furthermore, certain metalloporphyrin hosts are applicable to the selective extraction of low-abundance higher fullerenes from an industrial production source and also allow spectroscopic discrimination of chiral fullerenes.

Isolation and properties of small-bandgap fullerenes

Abstract: The diversity of molecular structures exhibited by fullerenes1 suggests a wide range of interesting and useful properties. Several fullerenes are now considered to be well characterized, but only minor variations in their chemical and physical properties have been observed2. Here we show that there are in fact two distinct classes of fullerenes, with some very different chemical properties. Members of the first class, typified by C60 and C70, have large energy gaps between the highest occupied and lowest unoccupied molecular orbitals (HOMO and LUMO), and are soluble in many organic solvents. The second, previously unrecognized class is represented by C74 and selected isomers of the higher fullerenes, such as that of C80 with icosahedral symmetry: these are either free radicals or have small HOMO–LUMO gaps. Like radical metallofullerenes, they are kinetically unstable and react readily to form insoluble, polymerized solids. These intermolecular bonds can be broken by electrochemical reduction. After reducing them to soluble anions, we have been able to isolate and characterize these new fullerenes.

Importance of the Donor:Fullerene Intermolecular Arrangement for High-Efficiency Organic Photovoltaics

Abstract: The performance of organic photovoltaic (OPV) material systems are hypothesized to depend strongly on the intermolecular arrangements at the donor:fullerene interfaces. A review of some of the most efficient polymers utilized in polymer:fullerene PV devices, combined with an analysis of reported polymer donor materials wherein the same conjugated backbone was used with varying alkyl substituents, supports this hypothesis. Specifically, the literature shows that higher-performing donor–acceptor type polymers generally have acceptor moieties that are sterically accessible for interactions with the fullerene derivative, whereas the corresponding donor moieties tend to have branched alkyl substituents that sterically hinder interactions with the fullerene. To further explore the idea that the most beneficial polymer:fullerene arrangement involves the fullerene docking with the acceptor moiety, a family of benzo[1,2-b:4,5-b′]dithiophene–thieno[3,4-c]pyrrole-4,6-dione polymers (PBDTTPD derivatives) was synthesi...