Topologic Features of Three Structures Based on I???Base Halogen Bonding |
Acta Crystallogr. 2005, A61, C363 |
T. Pilati, P. Metrangolo, D. Proserpio, G. Resnati |
Keywords: topology, crystal engineering, halogen bonding |
The halogen bonding, that is the n to sigma* electron donation from
Lewis bases to halogen atoms (Lewis acids) is an interaction that has
attracted an increasing attention, especially in haloperfluorocarbons
were the heavy halogen atom (I, Br) is highly polarized1. We have
recently studied the three component structure of the cryptate K.2.2.2
with KI and 1,8-diiodo-perfluorooctane showing a very unusual
borromean assembly of the superanion2. We present here other three
halogen-bonded supra-molecular arrays showing unusual topologic
features: the assembly of tetra(4-pyridyl)pentaerythritol . 1,4-diiodooctafluorobutane
1, tetra(4-pyridyl)pentaerythritol . 1,8-diiodohexadecafluorooctane
2, and tetra(4-pyridyl)pentaerythritol . tetra(4-
iodo-tetrafluorophenyl)pentaerythritol 3. The three structures present
macrocyclic interpenetrate assembly. 1, 2, 3 show 2D 5-fold 44 layers,
8-fold diamondoid class Ia, 10-fold diamondoid class IIIa topologies,
respectively.
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