The Origin of the Auxetic Effect in Prismanes: Bowtie Structure and the Mechanical Properties of Biprismanes.
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- 作者：Nir Pour† ; ; Eli Altus‡ ; ; Harold Basch† ; ; Shmaryahu Hoz*† ;
- 刊名：Journal of Physical Chemistry C
- 出版年：2009
- 出版时间：March 5, 2009
- 年：2009
- 卷：113
- 期：9
- 页码：3467-3470
- 全文大小：109K
- 年卷期：v.113,no.9(March 5, 2009)
- ISSN：1932-7455
文摘
Prismanes have been shown to exhibit negative Poisson’s ratio (auxetic behavior) for their internal rings and normal Poisson’s behavior for the terminal rings. Various [3], [4], [5], and [6] biprismanes were studied by using quantum mechanical ab initio calculations. The unusual mechanical behavior of prismanes upon stretching was traced to the relaxation of geometrical distortion existing in the ground state. The increase of the Poissonic effect on the ring size correlates well with the Thorpe−Ingold effect. In biprismanes where the CH units in the external rings are replaced by nitrogen, the effect is accentuated. Substitution of the hydrogens by fluorine atoms markedly reduces the effect, this being an interesting example of substituent effect on mechanical properties. This effect is attenuated in longer prismanes.