Characterization, luminescence and crystal structure of uranyl nitrate complexes with diphenyl-N-ethylphosphine amide and tripiperidinephosphine oxide

A study on pyrrolidone derivatives as selective precipitant for uranyl ion in HNO3

“…As seen from this table, significant differences are observed in the U1-O2-C1 moiety, i.e., the U1-O2 bond distance and the bend of U1-O2-C1 in UO 2 (NO 3 ) 2 (NCP) 2 are the smallest in three complexes. This is similar to results observed in UO 2 (NO 3 ) 2 (L P=O ) 2 (L P=O : triphenylphosphine oxide, hexaethylphosphoric triamide, and diphenyl-N-ethylphosphine amide) complexes, where the U-O(P) distances shorten with an increase in linearity of U-O-P angle [12,25,26]. Furthermore, the Table 2 Selected bond distances (Å) and angles ( • ) of UO 2 (NO 3 ) 2 (NMP) 2 (1), UO 2 (NO 3 ) 2 (NEP) 2 (2), and UO 2 (NO 3 ) 2 (NCP) 2 distance of U1-O1 in UO 2 (NO 3 ) 2 (NCP) 2 is longer than those in UO 2 (NO 3 ) 2 (L) 2 (L = NMP, NEP).…”

“…In our previous study [5], we found out that NO 3 − and cyclohexyl group of NCP play important roles in the selective precipitation, because CF 3 CO 2 − and CH 3 SO 3 − ions do not give precipitates under analogous conditions, and N-methyl-2-pyrrolidone (NMP) does not precipitate UO 2 2+ in HNO 3 solutions. Furthermore, in more recent study [7], we clarified that the structure of UO 2 (NO 3 ) 2 (NCP) 2 is similar to those of UO 2 (NO 3 ) 2 (L) 2 (L = unidentate oxygen donor ligands) [8][9][10][11][12], i.e., the equatorial site of UO 2 2+ is occupied by two trans NO 3 − and L ligands. However, the factors inducing unique precipitation ability of NCP are still ambiguous.…”

Uranyl complexes formed with a para-t-butylcalix[4]arene bearing phosphinoyl pendant arms on the lower rim. Solid and solution studies

“…The standard uranyl valence configuration 7s5 f 6d was found to be the most adequate for the ab initio calculations including relativistic effects, which yielded an optimized molecule in which the linearity of uranyl is practically maintained but not the U−O bond length of uranyl. In fact, the O−U−O angle found (178.8 • ) is comparable to the one for uranyl complexes with phosphoryl [59] and nitrate [60] donors (177-180 • ) but which are highly asymmetric. Several facBrought to you by | New York University Bobst Library Technical Services Authenticated Download Date | 5/31/15 1:11 PM tors exert symbiotic effects leading to this asymmetry: the size of the calixarene which does not permit complete inclusion of the uranyl cation, steric and electronic restrictions due to the linear geometry of uranyl, the mono-coordinate mode of nitrate, and coordinated water molecules.…”

“…The asymmetrical stretching frequency of the uranyl ion (ν asym U-O), usually observed between 910 and 960 cm −1 is strongly affected by changes in the chemical environment [6,43,59]. The IR spectrum of uranyl nitrate hexahydrate (where two water molecules and two bidentate nitrates are coordinated) reveals this vibration as a very strong band at about 940 cm −1 .…”

Synthesis, Characterization, and Crystal Structure of New Complex, Based on Proton Transfer to Uranium(VI) Complex

“…[20] Uranyl ion UO 2 2+ is quite peculiar both in its own structure and its coordination compounds. [21,22] The ion retains its identity over a wide range of vibrations in the experimental conditions, from a geometrical point of view, as a single particle. It has three fundamental vibrations: (i) non-degenerate symmetric stretching vibration ν1, normally infrared forbidden occurs in the range 900-800 cm -1 , (ii) non-degenerate asymmetric stretching vibrations ν 3 , which is infrared active occurs at ~1000-900 cm -1 , and (iii) doubly degenerate OUO bending vibration ν 2 is infrared active and appears at ~250 cm -1 .…”