Monoclinic and Triclinic Tetraisopropyl-p-phenylenediamine: To what Extent do nN/π Interactions Determine Structures?
✍ Scribed by Prof. Dr. Hans Bock; Dipl.-Chem. Ilka Göbel; Dipl.-Chem. Christian Näther; Dr. Zdenek Havlas; Prof. Dr. Angelo Gavezzotti; Dr. Giuseppe Filippini
- Book ID
- 102726952
- Publisher
- John Wiley and Sons
- Year
- 1993
- Tongue
- English
- Weight
- 517 KB
- Volume
- 32
- Category
- Article
- ISSN
- 0044-8249
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✦ Synopsis
servation of only a small calculated Pd-Pd overlap population.[2'l A structural indication for the existence of Pd-Pd bonding interactions is the fact that the Pd(2) and Pd(3) atoms are not centered in the tetrahedral B sites of the Ta,NiS, parent structure, but instead are displaced from the centers of these tetrahedral voids towards the two respective neighboring Pd atoms. The Ta-Fa interactions are weak, as expected from their large Fd-Ta distances (dTa-Ta: 3.713A).
The reasons for the preferential formation of the "filledin" Ta2NiQ, structure type with the tellurides are not yet clear. Geometric conditions cannot be the only cause since the respective radius relationships with the sulfides would also allow an occupation of the tetrahedral sites within the layers. A possible argument for the occurrence of the lattice distortions associated with the incorporation of the interstitial atoms as well as for the strong tendency for formation of the "filled-in" structure with the tellurides is the high polarizability of Te2-anions. Thus, lattice distortions should preferentially occur with "soft" lattices.