ISSN:
1573-1111
Keywords:
Cyclodextrin inclusion compound
;
metallocene
;
crystal structure
Source:
Springer Online Journal Archives 1860-2000
Topics:
Chemistry and Pharmacology
Notes:
Abstract The title metallocenium salts form crystalline 2:1 host:guest inclusion compounds withα-cyclodextrin, [(η5-C5H5)2M]PF6 · 2α-CD · 8H2O (1, M = Fe;2, M = Co;3, M = Rh). The X-ray crystal structures of1 and3, and the lattice constants, crystal system and space group of2 have been determined. Crystal data: triclinic, space groupP1 (No. 1),Z = 1;1,a = 13.865 (2) Å,b = 13.839 (2) Å,c = 15.520 (2) Å,α = 91.43 (2)°,β = 85.81 (2)°,γ = 120.22 (2)°, andR F = 0.089 for 4257 observed MoK α reflections [I 〉 3δ(I)];2,a = 13.810 (2) Å,b = 13.872 (2) Å,c = 15.560 (2) Å,α = 93.99 (2)°,β = 87.06 (2)°,γ = 120.04 (2)°;3,a = 13.756 (1) Å,b = 13.863 (1) Å,c = 15.561 (2) Å,α =94.39 (1)°,β = 86.92 (1)°,γ = 119.89 (1)°, andR F = 0.061 for 11142 observed MoK α reflections [I 〉 3δ(I)]. In the crystals of1 and3, two α-cyclodextrin molecules are arranged head-to-head to form a dimer by means of intermolecular hydrogen bonding across the secondary hydroxyl faces of adjacent α-CD monomers. The dimers are stacked along the crystallographicc axis to form a channel-type structure. The metallocenium cation is encapsulated within the cavity of the dimer, while the PF 6 − anion is located outside the cavity, being centered between the primary hydroxyl faces of adjacent dimers. Eight water molecules of hydration per asymmetric unit reside in the spaces between the α-CD columns. In view of the almost identical crystal data for2 a similar structure can be assumed for the cobaltocenium adduct.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF01066209
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