Synthesis, Structural, and Thermal Aspects of Dioxouranium(VI) Coordination Compounds of Semicarbazones Derived from 4‐Aminoantipyrine

Abstract A series of 18 new coordination compounds of dioxouranium(VI) with semicarbazones of 4‐aminoantipyrine, viz., 4[N‐(p‐dimethylaminobenzylidene)amino]antipyrine semicarbazone (DABAAPS), 4[N‐(2′‐nitrobenzylidene)amino]antipyrine semicarbazone (2′‐NO2BAAPS), and 4[N‐(3′‐nitrobenzylidene)amino]antipyrine semicarbazone (3′‐NO2BAAPS) of the general composition [UO2L2X2] (X = Br, I, or NCS), [UO2L2](ClO4)2, [UO2L(NO3)2], and [UO2L(OOCCH3)2] (L = DABAAPS, 2′‐NO2BAAPS, and 3′‐NO2BAAPS) were synthesized in non‐aqueous solution and characterized on the basis of elemental analyses, electrical conductivity, magnetic moments, and IR spectral studies. In all of the complexes, these ligands act as neutral tridentate (N, N, O) ligands. In all dioxouranium(VI) complexes, the ν1 and ν3 modes are assigned to 845–825 cm−1 and 930–910 cm−1, respectively. Wilson's G‐F matrix method was used to determine the stretching and interaction force constants from which the U–O bond distances were calculated using Badger's formula. The probable coordination number of U(VI) varies from 8–10 in these complexes. The thermal properties of these compounds are also discussed.