Open-framework sodium uranyl selenate and sodium uranyl sulfate with protonated morpholino-N-acetic acid

Abstract

The reaction of sodium N-morpholine acetate with selenic and sulfuric acid and uranyl nitrate results in the formation of two novel open-framework compounds, |Na(Hmfa)|[(UO2)2(SeO4)3(H2O)](H2O)2 (NaUSe) and [Na2(SO3OH)(Hmfa)]|(UO2)(SO4)2| (NaUS), respectively. Despite identical synthetic procedures, sulfate structure dramatically differs from selenate compound. Their common feature is an open-framework featuring two-dimensional system of channels occupied by protonated morpholino-N-acetic acid species. Coordination of Na atoms is different. In NaUSe, [(UO2)2 (SeO4)3(H2O)]2− layers are pillared by {Na2O8(H2O)2(Hmfa)2} complexes to form a microporous framework. In NaUS, UO7 and SO4 polyhedra of [(UO2)(SO4)2]2− chains share common oxygen atoms with Na-centered tetrameric complexes providing a three-dimensional integrity of the structure. Both of the compounds are characterized by IR spectroscopy.

Lattice dynamics and thermal transport of PbTe under high pressure

“…Details of this setup are given in Refs. [39,40]. The ILL experiment used a more recent and improved setup which allowed compression under strictly hydrostatic conditions using the 4:1 deuterated methanol-ethanol mixture which is known to stay fluid up to 10 GPa [39].…”

Framework Uranyl Silicates: Crystal Chemistry and a New Route for the Synthesis

“…Among uranyl silicates, the UO n and SiO 4 polyhedra commonly condense into microporous frameworks [24]. Though such architectures are known also among uranyl molybdates [25][26][27][28][29], selenates [30], chromates [31], vanadates [32,33], phosphates [34,35], sulfates, [36][37][38] and phosphonates [39], the silicate frameworks exhibit more complex and uncommon topologies. Comparable architectures have by now been reported only among uranyl germanates [40,41].…”

Secondary Role of Aliphatic and Heterocyclic Amines in the Formation of Low-Temperature Amine-Bearing U, Np, and Pu(VI) Chromates

“…In addition to the importance of the coordination chemistry of actinides complexes with theses anions as applied to the nuclear energy cycle, the purely chemical aspect of the problem is also quite interesting. Except for the isostructural series of more simple compounds like UO 2 XO 4 (X = S, Se, Cr, Mo, and W) or Cs 2 [(UO 2 ) 2 (XO 4 ) 3 ] (X = S, Se, and Cr), − the nonmonotonic variability in the composition, structure, and properties of the uranyl complexes with different tetrahedral anions is noted by many authors. − Despite the formal similarity between the SO 4 2– , SeO 4 2– , CrO 4 2– , and MoO 4 2– anions, the different nature of the central atoms (p- or d-) may have an effect on the role of the corresponding anion in the structure of complexes. The ability of tetrahedral anions to condensate with the formation of (X 2 O 7 ) n − pyranions, typical for complexes with p- and d-elements, does not always occur in uranyl compounds.…”