Fullerenes chemistry principles

Cycloadditions to [6,6]-double bonds of Cjq are among the most important reactions in fullerene chemistry. For a second attack to a [6,6]-bond of a C q monoadduct nine different sites are available (Figure 10.1). For bisadducts with different but symmetrical addends nine regioisomeric bisadducts are, in principle, possible. If only one type of symmetrical addends is allowed, eight different regioisomers can be considered, since attack to both e - and e"-positions leads to the same product. Two successive cycloadditions mostly represent the fundamental case and form the basis for the regioselectivity of multiple additions. In a comprehensive study of bisadduct formations with two identical as well as with two different addends, nucleophilic cyclopropanations, Bamford-Stevens reactions with dimethoxybenzo-phenone-tosylhydrazone and nitrene additions have been analyzed in detail (Scheme 10.1) [3, 9, 10]. 

Comparable alternations between the [6,6]- and [5,6]- bond lengths are observed in many fullerene adducts and higher fullerenes. Moreover, from the evaluation of many exohedral transformation of fullerenes, in particular Cjq, an important principle of fullerene chemistry can be deduced, namely minimization of[5,6]-douhle bonds in the lowest energy Kekule structure. Minimization of [5,6]-double bonds is... 

Principles and Perspectives of Fullerene Chemistry The closed shell systems 20 (N=2),... 

Seven Principles of Fullerene Chemistry a Short Summary... 

Here, a first review is provided which summarizes the more recent development framework modified fullerenes like cluster opened structures and heterofullerenes. The key steps for such framework modifications are always defined activations of the fullerene cluster due to specific covalent addition reactions. Therefore, the principles of covalent fullerene chemistry [3-8] will be considered first ... 

Addition reactions contain the largest synthetic potential in fullerene chemistry but they can also be used as a probe for screening the chemical properties of fullerene surfaces. Analysis of the nature of addition reactions, of geometric and electronic structures of educts and products allows one to deduce reactivity principles which are the central subject of this article. One striking conclusion is the following the fullerenes drew attention to a mostly overlooked chemistry criterion - the shape dependence of reactivity. This contribution focuses on the reactivity principles of Cgg as the most important and most intensively investigated fullerene. The addition chemistry of the higher fullerenes follows similar principles. 

Reactivity principles of Cgg which were deduced in preceding reviews [3,5] are still valid. However, the progress in the field of fullerene chemistry continuously increases our knowledge and allows us to refine the rules for the reactivity of this spherical carbon cluster. Based on the present state-of-the-art the following principles of Cgo chemistry are summarized. 

O. Moradi, M. Yari, K. Zare, B. Mirza, and F. Najafi, Carbon nanotubes A review of chemistry principles and reactions, Fullerenes, Nanotubes and Carbon Nanostructures, 20 (2), 138-151,2012. 

The chemistry of Ceo and that of a series of higher fullerenes has been intensively Investigated m the last 10 years. Various areas of fullerene chemistry as well as principles of fullerene reactivity were summarized in a variety of reviews. Here we... 

The strain introduced in the addition compounds causes them to readily eliminate and revert back to the parent fullerene. This makes mass spectroscopic identification of derivatives particularly difficult. A further difficulty encountered in the chemistry of fullerenes lies in the multitude of addition products that can, in principle, be obtained. For example, for C60 the number of products discounting isomers that can be produced on addition of a reagent X2 will equal the number of double bonds, i.e. 30. If isomers are included then many hundreds are possible. Development of C60 chemistry is therefore very much more difficult than that of benzene. It is also complicated by the low solubility of C60 in organic solvents, and by the fact that derivatives are themselves mostly more soluble, which facilitates polysubstitution hydroxy and amino derivatives of C60 are water-soluble. The additions are described under the two main categories outlined above. 

F. Langa and J.-F. Nierengarten (eds.), Fullerenes Principles and Applications, Royal Society of Chemistry, Cambridge, 2007. 

The chemistry and physics of ftillerenes have constituted one of the most fast growing research fields during the last decade [90]. A summary of the early results for the second hyperpolarizability can be found in [91, 92]. There are a number of factors that make comparison of these results difficult, for instance the type of optical process, the phase of the samples, and the reference standard [91, 93]. The theoretical results, on the other hand, seem to be more consistent, especially among those from the first-principle calculations, such as ab initio Hartree-Fock and the density functional theory (DFT) methods [14, 89, 94, 95], The recent applications of time-dependent DFT [14, 96] to NLO properties of the fullerenes has improved the situation considerably. 

E.Nierengarten Fullerenes principles and applications Royal Society of Chemistry 2007, ISBN 9780854045518 Fullerenes, Nanotubes and Carbon Nanostructures Marcel Dekker Inc New York, on line series on World Wide Web.online, N.Chaniotakis Fullerenes-bifunotionalisation (nanostructured for biosensing) in Nanomaterials for Biosensors , C. Kumar ed., Wiley-VCH, 2007, ISBN 978-3-527-31388-4 C.N.Kramer Fullerene research advances Nova Science Publishers Inc 2007, ISBN 9781600218248 MJ.,ang Progress in fullerene research Nova Science Publishers Inc 2007, ISBN 9781600218415 S.Margadonna Fullerene-related materials recent advances in their chemistry and physics Springer 2007, ISBN 9781402044588.]... 

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