Sharma, Pankaz K and Jemmis, Eluvathingal D and Vidya, Ramdas and Mehta, Goverdhan (1999) [n]peristylanes and [n]oxa[n]peristylanes (n = 3-6): A theoretical study. In: Perkin Transactions 2 (2). 257-262 .
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Theoretical studies at the HF and Becke3LYP levels using 6-31G* basis sets were carried out on a series of [n]peristylanes and [n]oxa[n]peristylanes (n = 3-6) to understand their structure and energetics. The structures of the - and peristylanes (1, 2) and their era-derivatives (5, 6) were calculated to have the anticipated high symmetry, C-nv. In contrast, a C-s structure (9) at HF/6-31G* and another (25) at the Becke3LYP/6-31G* level were calculated for the oxaperistylane. The energy difference between them is extremely small even though there are major differences in the structures indicating every soft potential energy surface: On the other hand, the potential energy surface of oxaperistylane is not as soft. Similar structures were also calculated for the top rings. Calculations on the seco-compounds 11-14 and 15-19 (Table 4) indicate that there is no unusual strain involved in the formation of 27 from 19. The Li+ interaction energies of the [n]oxa[n]peristylanes are 61.7 (n = 3), 72.8 (n = 4), 84.2 (n = 5) and 91.7 (n = 6) kcal mol(-1) at the Becke3LYP/6-3IG* level. Dramatic differences between the C-C bond lengths obtained from the solid state X-ray diffraction studies and those from the calculations for the [n]oxa[n]peristylanes were also observed.
|Item Type:||Journal Article|
|Additional Information:||Copyright of this article belongs to Royal Society of Chemistry.|
|Department/Centre:||Division of Chemical Sciences > Organic Chemistry|
|Date Deposited:||29 Jun 2011 05:52|
|Last Modified:||29 Jun 2011 05:52|
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