How Small Can a Catenane Be?

详细信息    查看全文

• 作者：Xuejun Feng ; Jiande Gu ; Qun Chen ; Jenn-Huei Lii ; Norman L. Allinger ; Yaoming Xie ; Henry F. Schaefer ; III
• 刊名：Journal of Chemical Theory and Computation
• 出版年：2014
• 出版时间：April 8, 2014
• 年：2014
• 卷：10
• 期：4
• 页码：1511-1517
• 全文大小：381K
• 年卷期：v.10,no.4(April 8, 2014)
• ISSN：1549-9626

文摘

Catenanes are playing an increasingly important role in supramolecular chemistry. In attempting to identify the minimum number of carbon atoms in a viable catenane, the B3LYP, BP86, M06-2X, MM3, and MM4 methods were applied to study representative [2]catenane models, which consist of two mechanically interlocked saturated n-cycloalkanes ([C_nH_2n]₂). The structures, energy variations, and electron density differences vary nearly monotonically from n = 18 to 11. For example, the B3LYP/DZP++ dissociation energies [C_nH_2n]₂ 鈫?2C_nH_2nare 101, 121, 159, 191, 222, 252, 290, and 323 kcal/mol from n = 18 to 11, respectively. However, there is much variation among the energetic predictions with the B3LYP, BP86, M06-2X, MM3, and MM4 methods. The distances of the longest C鈥揅 single bond in each catenane are 1.593 (n = 18), 1.604 (n = 17), 1.631 (n = 16), 1.640 (n = 15), 1.667 (n = 14), 1.669 (n = 13), 1.680 (n = 12), and 1.689 脜 (n = 11). These results display something of a shoulder in the vicinity of n = 14. This may suggest that [C₁₅H₃₀]₂ is the smallest catenane that will resist fragmentation under specified laboratory conditions.