Help Privacy Policy Disclaimer
  Advanced SearchBrowse




Journal Article

[2.2]Paracyclophane: theoretical study of its lower excited states and of the zero-field splitting parameters D


Vogler,  Helmut
Department of Organic Chemistry, Max Planck Institute for Medical Research, Max Planck Society;

Fulltext (restricted access)
There are currently no full texts shared for your IP range.
Fulltext (public)
There are no public fulltexts stored in PuRe
Supplementary Material (public)
There is no public supplementary material available

Vogler, H. (1982). [2.2]Paracyclophane: theoretical study of its lower excited states and of the zero-field splitting parameters D. Molecular Physics, 47(5), 1179-1193. doi:10.1080/00268978200100872.

Cite as: https://hdl.handle.net/21.11116/0000-0005-11B1-F
The lower excited singlet and triplet states and the zero-field splitting parameters D of [2.2]paracyclophane are studied within a semiempirical π theory which takes into account overlap effects between the two benzene rings, transanular and through-bond interaction via the methylene bridges. Whereas the singlet energies depend strongly on the through-bond interaction and the mutual polarization of σ core and π system this is not the case for the energies and zero-field splitting parameters D of the two lowest triplet states. The deformations of the benzene rings in [2.2]paracyclophane lead only to a small decrease of the excitation energies of about 0·2 eV. The D parameter can be written as a sum D = DA + DB + DAB with the intrasubunit contributions DA and DB of the conjugated subunits A and B of the phane and an intersubunit term DAB . We demonstrate that the deformations reduce the intrasubunit terms DA and DB and that they are crucial for the decrease of the D values of [2.2]paracyclophane with respect to p-xylene. The difference between the D values of the first and second triplet states is governed by the intersubunit term DAB which has a different sign in the two states. However, this difference does not depend markedly on the transanular interaction. A further reduction of DA and DB in the first triplet state only is caused by transanular interaction by means of symmetrical charge-transfer terms in the wavefunction.