Endohedral fullerenes applications

Endohedral fullerenes, which contain metal atoms or small molecules inside the carbon cages, hold great promise for application in optoelectronic devices because of their fullerene-like and metallic properties. However, their investigations are limited by extremely low yields of these fullerenes (mg pg range). IR and Raman studies of endohedral fullerenes are important in elucidating the nature of interaction between the carbon cage and encapsulated species. Electronic structures and spectroscopic properties of endohedral fullerenes have been reviewed by Guha and Nakamoto [1549]. 

Compounds of Carbon ) has been expanded to show significant applications of vibrational spectroscopy to the structural determination of fullerences, endohedral fullerenes, and carbon nanotubes. Vibrational data on a number of novel inorganic compounds prepared most recently have been added throughout Chapter 2. 

The prototype of all fullerenes is Buckminsterfullerene ,. Since it is the most abundant fiillerene obtained from macroscopic preparation procedures such as the classical Kratschmer-Huffman method, its chemical and physical properties were developed in very quick sucession soon after it became available in 1990. The icosahedral football shaped Buckminsterfrdlerene 60 is now the most intensively studied molecule of all. Many principles of the chemistry of C , are known. These allowone to tailor design new fuUerene derivates with specific properties useful for biological applications or as new materials. The main types of fullerene derivative are exohedral addition products, endohedral fullerenes, heterofullerenes and cluster opened systems. Whereas many examples of the first two groups are already known, sophisticated methods for the synthesis of the latter two groups have started to emerge only recently. 

However, despite this remarkably high efficiency, ICBA has not shown good performance when used with other low-bandgap polymers. An alternative path to modify the LUMO level of fullerenes for OPV applications was using expensive endohedral fullerenes introduced by Drees and coworkers [85]. 

Some proposed applications of endohedral fullerenes include MRI contrast agents, radiopharmaceuticals, photo-voltaics, and quantum computing. While some of the proposed applications have been recently achieved, a problem that has to be overcome for most applications is the insolubility of... 

An endohedral fullerene, LusNcgCgo, has been used as an acceptor material in organic photovoltaic applications. For processing into devices the endohedral fullerene must be exohedrally modified to overcome the insolubility of... 

A possible application of endohedral fullerenes is radiopharmaceuticals, where the toxic metal, which is used as a radiotracer, is protected by the fiillerene cage. A Ho-based endohedral fullerene was used as a radiotracer. It traveled to all organs except those with limited blood flow. ... 

Since their discovery endohedral flillerenes have been extensively investigated because of their novel structure and properties [1]. Electrical properties have been of major interest owing to a variety of possible applications ranging from qubits for quantum computation [2] to organic photovoltaic devices [3], Our interest in this connection lies in the theoretical determination of the linear and nonUnear optical properties, i.e. the (hyper)polarizabilities, of these materials. For that purpose we have chosen initially to study the prototypical metal endohedral fullerene, Li C6o, and its cation [Li C6o] . ... 

Two other selected examples of the application of INADEQUATE to fullerenes focus on endohedral metallofullerenes. The first is based on the reported mapping of the bond connectivity in the carbon cage of La C82 anion, [La C82A]+75 The 13C NMR spectrum of [La C82A] showed 17 distinct lines of near-equal intensity and 7 lines of half the intensity. This is expected (17x4 + 2x7 = 82) for a molecule with a C2l. symmetry. 

Studies of endohedral metallofullerenes directed to application have been reported since the metallofullerenes are structurally and electronically much more unique than the normal empty fullerenes. 

In recent studies [62, 63], closed shell defects of the fullerene molecule, Cs8j C59, and also the C( C endohedral complex, were considered. This class of defects is promising for technological applications because the investigated species are similar to the ideal Cgo, do not change the neutral state of the material, and are thermodynamically stable. 

Fullerenes—or cage compounds built exclusively from carbon atoms—and their metal-containing derivatives, metaUofuUerenes, were first observed in the gas phase by Kroto et al. [1,2] less than 20 years ago and prepared in crystalline form by Kratschmer et al. [3] less than 15 years ago. StiU, an enormous amount of observed and computed data has been obtained during this time (see, e.g. recent surveys on fullerenes [4-8] and endohedral metallofullerenes [9,10]). In addition to spheroidal fullerene cages, fullerene science also deals with other objects like elongated cylindrical bodies known as nanotubes, prepared by lijima [11] soon after mastering the fullerene synthesis, nanocones [12] or peapods [13]. AU the species exhibit a substantial application potential, especially for molecular electronics [14]. 

Abstract We report here a review of our recent efforts at understanding and predicting reactivity and regioselectivity of endohedral (metallo)fullerenes and their parent free fullerenes. The effect of encapsulation of trimetallic nitrides or noble gas atoms/dimers was shown to have a profound impact on the stability and reactivity of fullerene compounds. It is not just the encapsulation, but in particular the nature of the species that is encapsulated that determines how (un)reactive the fullerene becomes. These findings have important consequences for future applications of (metallo)fullerenes in biomedicine and (nano)technology. 

Since their discovery, fullerenes and their derivatives have been the subject of very extensive research. One of the topics investigated intensively are the linear and nonlinear optical (NLO) properties, owing to a variety of possible applications. Here we review some of the recent work of our group in this area, which is concerned with the ab-initio calculation of molecular NLO properties of two different kinds of fullerene derivatives, a) substituted 1,2-dihydro fullerenes and b) fullerenes endohedrally doped with atoms or small molecules. Apart from the purely electronic response, we also focus on the vibrational contributions to the NLO response, that is, to the response of the nuclei to the external electric fields. 

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