L. B. Sveshnikova

Conformational rearrangement of 18-crown-6 upon the formation of aquanitratouranyl complexes: The refinement of crystal and molecular structures for [UO2(NO3)2(H2O)2] · 2H2O · 18C6

Comparing the geometry of [UO2(NO3)2(H2O)2] · 2H2O · 18C6 (18C6 = C12H24O6) and IR spectroscopic data, we propose correlations between the conformation of an ethylene oxide unit of 18-crown-6 and the conformation-sensitive frequency in the IR spectrum. Spectral conformational analysis verifies the composition of the 18-crown-6 conformer in the [UO2(NO3)2(H2O)2] · 18C6 complex whose structure is known. The distribution character of hydrogen bonds that retain crown ether molecules in aquanitratouranyl complexes is shown to influence the conformational uniformity of ethylene oxide units of the macrocycle.

Crystal and molecular structure of ammonium trinitratouranylate NH4[UO2(NO3)3]

Ammonium trinitratouranylate NH4[UO2(NO3)3] (I) single crystals have been synthesized by the reaction of aqueous solutions of diaquadinitratouranyl tetrahydrate and ammonium nitrate in the presence of nitric acid. The structure of the complex has been studied by X-ray diffraction analysis: space group

Crystal and molecular structure of diaquadinitratouranyl dihydrate [UO2(NO3)2(H2O)2] · 2H2O

R\bar 3c

X-ray diffraction refinement of the structure of diaquadinitratouranyl tetrahydrate [UO2(NO3)2(H2O)2] • 4H2O

, a = 9.361(2), c = 18.883(4) Å; V = 1433.0(5) Å3, and Z = 6. The structural units of the NH4[UO2(NO3)3] crystal—NH4+ cations and [UO2(NO3)3]− complex anions with three bidentate cyclic nitrato groups—are on crystallographic axes

ACETATOAQUA URANYL 18-CROWN-6 COMPLEXES, UO2(CH3COO)(OH)(H2O)2 . 18-CROWN-6 AND UO2(CH3COO)2 . (H2O)2 . (H2O)2 . 18-CROWN-6 : CRYSTAL AND MOLECULAR ST RUCTURES

\bar 3

The synthesis and crystal and molecular structure of a diazonia-18-crown-6 tetranitratouranylate, [C12H28O4N2] . [UO2(NO3)4]

. A complex three-dimensional packing arranged by the electrostatic attraction forces between counterions and the N-H...O hydrogen bonds between ammonium cations and trinitratouranylate anions is realized in the structure. X-ray diffraction analysis results are confirmed by IR spectra of NH4[UO2(NO3)3].