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Vol. 27 No. 5
September-October 2005

Making an imPACt

Recent IUPAC technical reports and recommendations that affect the many fields of pure and applied chemistry.
See also www.iupac.org/publications/pac

Numbering of Fullerenes (IUPAC Recommendations 2005)

F. Cozzi, W. H. Powell, and C. Thilgen

Pure and Applied Chemistry
Vol. 77, No. 5, pp. 843–923 (2005)

One numbering system, exemplified in this report, for compounds (C50-D5h)[5,6]fullerene.

In 1995, a preliminary survey on numbering and nomenclature for fullerenes was prepared (PAC 69, 1411–1434 [1997]). It described two types of names for fullerenes, one proposed by some workers in the field and another one used by the Chemical Abstracts Service (CAS); and two systems for numbering fullerene skeletons, one proposed in a publication by R. Taylor (J. Chem. Soc., Perkin Trans. 2, 813–824 [1993]), and one published by CAS (J. Chem. Inf. Comp. Sci. 35, 969–978 [1995]). In addition, alternative methods for naming derivatives of fullerenes were discussed. More recently, a document appeared reporting IUPAC recommendations for the nomenclature for the C60-Ih and C70-D5h(6) fullerenes and their derivatives (PAC 74, 629–695 [2002]). This report was limited to these fullerenes because there are only a small number of known derivatives of only a few other fullerenes.

This paper contains recommendations for the numbering of fullerenes other than (C₆₀-I_h)[5,6]fullerene and (C₇₀-D_5h₍₆₎)[5,6]fullerene and contains recommendations for numbering a wide variety of fullerenes of different sizes, with rings of different sizes, from C₂₀ to C₁₂₀, and of various point group symmetries, including low symmetries such as C_s, C_i, and C₁, as well as many fullerenes that have been isolated and well characterized as pristine carbon allotropes or as derivatives. These recommendations are based on the principles established in the earlier publication and aim at the identification of a well-defined and preferably contiguous helical pathway for numbering. Rules for systematically completing the numbering of fullerene structures for which a contiguous numbering pathway becomes discontiguous are presented.

www.iupac.org/publications/pac/2005/7705/7705x0843.html