Crystal structures of benzo-18-crown-6 complexes with oxonium hexafluorotantalate and oxonium hexafluoroniobate

Autor: Edward V. Ganin, N. G. Furmanova, Wen-Jwu Wang, Vladimir O. Gelmboldt, Yu. A. Simonov, I. A. Verin, Marina S. Fonari
Rok vydání: 2006
Předmět:
Zdroj: Crystallography Reports. 51:804-810
ISSN: 1562-689X
1063-7745
DOI: 10.1134/s1063774506050099
Popis: The crystal structures of [(benzo-18-crown-6) · H3O]TaF6 and [(benzo-18-crown-6) · H3O]NbF6 complex compounds are determined by X-ray diffraction. It is revealed that the tantalum complex has two polymorphic modifications, namely, the monoclinic (I) and orthorhombic (II) modifications. The unit cell parameters of these compounds are as follows: a = 14.784(2) A, b = 8.390(4) A, c = 18.005(6) A, β = 95.78(2)°, Z = 4, and space group P21/n for modification I; and a = 8.456(2) A, b = 21.967(5) A, c = 24.122(5) A, Z = 8, and space group Pbca for modification II. The orthorhombic niobium complex [(benzo-18-crown-6) · H3O]NbF6 with the unit cell parameters a = 8.454(1) A, b = 21.943(3) A, c = 24.127(4) A, Z = 8, and space group Pbca (III) is isostructural with tantalum complex II. The oxonium cation in complexes I–III is encapsulated by the crown ether and thus forms one ordinary and two bifurcate hydrogen bonds with the oxygen atoms of the crown ether. This macrocyclic cation is bound to the anions through the C-H ...F contacts (H...F, 2.48–2.58 A).
Databáze: OpenAIRE