Supramolecular structures for determination and identification of the bond lengths in novel uranyl complexes from their infrared spectra

Novel dioxouranium (VI) heterochelates with neutral bidentate compounds (L_n) have been synthesized. The ligands and the heterochelates [UO₂(L_n)₂(O₂NO)₂] were confirmed and characterized by elemental analysis, ¹H NMR, UV.–Vis, IR, mass spectroscopy, X-ray diffraction and thermogravimetric analysis (TGA). IR spectral data suggest that the molecules of the Schiff base are coordinated to the central uranium atom (ON donor). The nitrato groups are coordinated as bidentate ligands. The thermodynamic parameters were calculated using Coats–Redfern and Horowitz–Metzger methods. The ligands (L_n) and their complexes (1–3) showed the υ₃ frequency of UO₂²⁺has been shown to be an excellent molecular probe for studying the coordinating power of the ligands. The values of υ₃ of the prepared complexes containing UO₂²⁺ were successfully used to calculate the force constant, F_UO (1n 10⁻⁸N/Å