Searching for stable hept-C62X2 (X = F, Cl, and Br): Structures and stabilities of heptagon-containing C62 halogenated derivatives
✍ Scribed by Lili Sun; Shuwei Tang; Yingfei Chang; Zhanliang Wang; Rongshun Wang
- Publisher
- John Wiley and Sons
- Year
- 2008
- Tongue
- English
- Weight
- 147 KB
- Volume
- 29
- Category
- Article
- ISSN
- 0192-8651
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✦ Synopsis
Abstract
To determine the geometries of the most stable hept‐C~62~X~2~ (X = F, Cl, and Br) isomers, all 967 possible hept‐C~62~F~2~ isomers have been orderly optimized using AM1, HF/STO‐3G, B3LYP/3‐21G, and B3LYP/6‐31G* methods, and chlorofullerenes and bromofullerenes, which are isostructural with five most stable hept‐C~62~F~2~ isomers, were regarded as candidates of the most stable isomer, and optimized at the B3LYP/6‐31G* level. The results reveal that 2,9‐ and 9,62‐hept‐C~62~X~2~ (X = F, Cl, and Br) are the two most stable isomers with slight energy difference. The halogenation releases strain energy of hept‐C~62~, and all halogenated fullerenes are more chemically stable than hept‐C~62~ with lower E~HOMO~ and higher E~LUMO~. All five most stable hept‐C~62~X~2~ (X = F, Cl, and Br) isomers are energetically favorable, and their thermodynamic stability decreases along with the increase of sizes of addends. Only hept‐C~62~F~2~ isomers show high thermodynamic stability, and they are potentially synthesized in experiments. 59,62‐squ‐C~62~X~2~ (X = F, Cl, and Br) were computed for comparison, and they are found to be more stable than their heptagon‐containing isomers. © 2008 Wiley Periodicals, Inc. J Comput Chem 2008