Nomenclature for the C60-Ih and C70-D5h(6) fullerenes (IUPAC Recommendations 2002)

Abstract

Republication or reproduction of this report or its storage and/or dissemination by electronic means is permitted without the need for formal IUPAC permission on condition that an acknowledgmentAbstract: Fullerenes are a new allotrope of carbon characterized by a closed-cage structure consisting of an even number of three-coordinate carbon atoms devoid of hydrogen atoms. This class was originally limited to closed-cage structures with 12 isolated five-membered rings, the rest being six-membered rings.Although it was recognized that existing organic ring nomenclature could be used for these structures, the resulting names would be extremely unwieldy and inconvient for use. At the same time it was also recognized that established organic nomenclature principles could be used, or adapted, to provide a consistent nomenclature for this unique class of compounds based on the class name fullerene. However, it was necessary to develop an entirely new method for uniquely numbering closed-cage systems.This paper describes IUPAC recommendations for naming and uniquely numbering the two most common fullerenes with isolated pentagons, the icosahedral C 60 fullerene and a D 5h -C 70 fullerene. It also describes recommendations for adapting organic nomenclature principles for naming fullerenes with nonclosedcage structures, heterofullerenes, derivatives formed by substitution of hydrofullerenes, and the fusion of organic rings or ring systems to the fullerene cage. Finally, this paper suggests methods for describing structures consisting of two or more fullerene units and for denoting configurations of chiral fullerenes and their derivatives. CONTENTS

Preparation of Open‐Cage Fullerenes and Incorporation of Small Molecules Through Their Orifices

“…Formation of the cobalt derivative 23 is an exception. [16] It was prepared from the thermal reaction of 3 with CpCo(CO) 2 (cyclopentadienylcobalt dicarbonyl, where Cp ¼ C 5 H 5 ). The cobalt inserts into the 5,6-junction on the hexagon where two carbons are already inserted.…”

“…IR and mass spectroscopy (MS) data of the film suggest formation of a dicarbonyl fullerene derivative C 60 (O) 2 . Calculation results agree with the opening of a double bond at the 6,6-junction.…”

“…[2] Through a suitable orifice, one or more atoms or small molecules may be inserted into the cavity of the fullerene cage to form endohedral complexes. These compounds are different from those endohedral fullerenes with a perfect closed spherical cage.…”

Nonsymmetrically Substituted Uranyl-Salophen Receptors: New Opportunities for Molecular Recognition and Catalysis

“…The peculiarity of these systems is that the uranyl ion is not a stereogenic centre in the strict sense, but with its bulkiness dissymmetrises the entire structure, imposing a curvature in an otherwise planar ligand. The use of the expression "inherently chiral" for such complexes was suggested to us by the implicit analogy with calix [4]arenes 27 and fullerenes 28 since in all these compounds chirality arises from the introduction of a curvature in an ideal planar structure that is devoid of symmetry axes in its bidimensional representation. 29 Consequently in all the derivatives referred to as "inherently chiral" racemisation occurs, or would occur at least in principle, through inversion of the curvature.…”

Fulereno[C60]: química e aplicações

“…Até hoje, oito fulerenos estáveis já foram isolados em quantidades significativas, sendo os mesmos denominados [60-I h ], [70-D 5h ], [76-D 2 ], [78-D 3 ], [78-C 2v [84-D 2d (II)] em função do número de carbonos que os formam, do grupo pontual de simetria da molécula e do número do possível regioisômero. 1 Dentre estes fulerenos, a molécula de simetria I h formada por 60 átomos de carbono, o buckminsterfulereno, fulereno [C 60 ] ou simplesmente C 60 é, sem dúvida, o mais abundante e representativo. O C 60 tem a estrutura de um icosaedro truncado não regular de 32 faces (20 hexágonos e 12 pentágonos) com 30 ligações carbono-carbono situadas nos vértices das fusões entre pentágonos e hexágonos.…”