The stabilization of fused-pentagon fullerene molecules

• Published in: Nature chemistry Vol. 1; no. 6; pp. 450 - 460
• Main Authors: Huang, Rong-Bin, Xie, Su-Yuan, Tan, Yuan-Zhi, Zheng, Lan-Sun
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 01.09.2009; Nature Publishing Group
• Subjects: Analytical Chemistry; Biochemistry; Carbon; Chemical properties; Chemistry; Chemistry and Materials Science; Chemistry/Food Science; Experimental methods; Fullerenes; Fullerenes - chemistry; Inorganic Chemistry; Metal ions; Models, Molecular; Molecular Structure; Organic Chemistry; Physical Chemistry; Research methodology; review-article
• ISSN: 1755-4330; 1755-4349
• DOI: 10.1038/nchem.329

The most stable fullerenes obey the isolated-pentagon rule (IPR): hexagons of carbon atoms entirely surround pentagons to minimize strain. Recently, some examples of fused-pentagon fullerenes have been reported and this Review summarizes current work to stabilize non-IPR fullerenes. The isolated pentagon rule (IPR) is now widely accepted as a general rule for determining the stability of all-carbon fullerene cages composed of hexagons and pentagons. Fullerenes that violate this rule have been deemed too reactive to be synthesized. The stabilization of non-IPR endohedral fullerenes depends on charge transfer from the encapsulated metal clusters (endoclusters) to fullerene cages, the electronic properties of empty all-carbon cages, the matching size and geometries of fullerene and endocluster, as well as the strong coordination of the metal ions to fused pentagons. The stability of non-IPR exohedral fullerenes can be rationalized primarily by both the 'strain-relief' and 'local-aromaticity' principles. This Review focuses on recent work on stabilization of non-IPR fullerenes, including theoretical and empirical principles, experimental methods, and molecular structures of fused-pentagon fullerenes characterized so far. The special chemical properties of non-IPR fullerenes that distinguish them from IPR-satisfying ones are also emphasized.