Correlation between the out-of-Plane Components of Magnetizability and Central Magnetic Shielding in Unsaturated Cyclic Molecules
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- 作者：Stefano Pelloni ; Paolo Lazzeretti
- 刊名：Journal of Physical Chemistry A
- 出版年：2011
- 出版时间：May 5, 2011
- 年：2011
- 卷：115
- 期：17
- 页码：4553-4557
- 全文大小：788K
- 年卷期：v.115,no.17(May 5, 2011)
- ISSN：1520-5215
文摘
A simple classical model of magnetic-field induced 蟺-electron flow is discussed, showing that the contribution to the 蟽 out-of-plane component of the virtual magnetic shielding provided by 蟺-ring currents, at points P along the Cn axis of cyclic planar unsaturated hydrocarbons CnHn with Dnh symmetry, in the presence of a magnetic field Bext at right angles to the 蟽h plane, is, with good approximation, connected with the 蟺-electron contribution to the out-of-plane component of the magnetizability, 尉. The relationship is 蟽(h) = 鈭?渭0/2蟺)(s2 + h2)鈭?/2尉, where s is the distance of a C nucleus from the center of the carbon ring, and h is the distance of P from 蟽h. The ring current susceptibility, that is, the strength of the 蟺 currents, expressed in nA/T (nano amp猫re per tesla) within the SI system of units, is given by 鈭?i>I/鈭?i>Bext = 鈭捨?sub>/(蟺s2), which can be used as a reliable virtual measure of magnetotropicity and relative 蟺-electron mobility in isoelectronic systems. Criteria for the practicality of the proposed ring current model are discussed.