3.4.3. Systematic numbering for (C₄₄-C₁)[5,6]fullerene

This fullerene contains twelve six-membered rings shown as A to L in Fig. 33a (smaller-font letters denote rings away from the viewer; larger-font, bold letters denote rings closer to the viewer). Among these, rings C, I, and K are preferred according to Fu-3.4.1 to begin the numbering, since they contain the higher-ranking atoms at the first point of difference. From these rings there are in principle thirty-six pathways to be examined. To reduce the number of pathways to be actually examined, the six pathways featuring the three 6,6,6 atoms at the first three positions are examined first, since, if contiguous, they will be preferred to all other possible pathways according to Fu-3.4.2. Only the two pathways beginning in ring I (clockwise from atom a, and anticlockwise from atom c in Fig. 33b, which shows a different view of (C₄₄-C₁)[5,6]fullerene) lead to contiguous spiral numberings. These are shown in Figs. 33c and 33d. These numbering sequences are compared using Fu-3.4.2 to discover that there is a 6,6,5 atom at position 23 in the sequence of Fig. 33c and a 6,5,5 atom at the same position in the sequence of Fig. 33d. The former is therefore preferred. The configuration of the shown enantiomer is (^f,sA) [ref 4].

Fig. 33. Systematic numbering of (^f,sA)(C₄₄-C₁)[5,6]fullerene

4. International Union of Pure and Applied Chemistry, Division of Organic Chemistry, Commission on Nomenclature of Organic Chemistry. "Nomenclature for the (C₆₀-I_h) and (C₇₀-D_5h(6))[5,6]fullerenes (IUPAC recommendations 2002)", Pure Appl. Chem. 2002, 74, 629-695.

5. P.W. Fowler and D.E. Manolopoulos, An Atlas of Fullerenes, Clarendon Press, Oxford, 1995