Organic Functionalization of Uranyl Peroxide Clusters to Impact Solubility

Abstract

Benzene-1,2-diphosphonic acid (Ppb) was introduced into the uranyl peroxide cluster system, resulting in three Ppb-functionalized uranyl peroxide clusters, (UO 2 ) 20 (O 2 ) 20 (C 6 H 4 P 2 O 6 ) 10 40 − (U 20 Ppb 10 ), ( U O 2 ) 2 6 ( O 2 ) 3 3 ( C 6 H 4 P 2 O 6 ) 6 3 8 − ( U 2 6 P p b 6 ) , a n d (UO 2 ) 20 (O 2 ) 24 (C 6 H 4 P 2 O 6 ) 632− (U 20 Ppb 6 ). Dissolution experiments were performed for the potassium salts of U 20 Ppb 10 and U 26 Ppb 6 , which revealed the capacity of U 20 Ppb 10 to dissolve in the organic solvent dimethyl sulfoxide (DMSO). Unlike U 20 Ppb 10 , the K salt of U 26 Ppb 6 did not dissolve in DMSO but was more soluble in water, perhaps due to the lower proportion of Ppb ligands in its structure. In this work, U 20 Ppb 10 and U 20 Ppb 6 formed as potassium salts and both adopt the fullerene topology of previously reported U 20 . U 20 contains 20 uranyl peroxide units and encapsulates 12 Na cations. It is not possible for unfunctionalized U 20 to incorporate 12 K cations owing to space constraints, as is the case in the new clusters reported here. Transformation of U 20 Ppb 10 in water over time to produce U 24 was observed, possibly owing to its ability to incorporate K cations, which have been associated with the formation of U 24 .

Recent advances in uranium-containing polyoxometalates

“…86 The reaction of Ppb and UO 2 (NO 3 ) 2 in a basic solution could also result in three new organic–inorganic hybrid uranyl peroxide clusters [(UO 2 ) 20 (O 2 ) 20 (Ppb) 10 ] 40− , [(UO 2 ) 26 (O 2 ) 33 (Ppb) 6 ] 38− , and [(UO 2 ) 20 (O 2 ) 24 (Ppb) 6 ] 32− . 89 The two {U 20 } clusters both showed similar fullerene topology, while the {U 26 } cluster exhibited a distorted polyhedron with more than 15 faces. Nyman investigated the influence of three organic solvents (acetone, CH 3 CN, and EtOH) in the synthesis of different fragments of uranyl peroxide clusters.…”

“…Burns also used high-temperature drop solution calorimetry to study the enthalpies of formation of several uranyl peroxide clusters and the disassembly and assembly process from 89 The two {U 20 } clusters both showed similar fullerene topology, while the {U 26 } cluster exhibited a distorted polyhedron with more than 15 faces. Nyman investigated the influence of three organic solvents (acetone, CH 3 CN, and EtOH) in the synthesis of different fragments of uranyl peroxide clusters.…”

Synthetic and Structural Chemistry of Uranyl-Amidoxime Complexes: Technological Implications

“…There has been an explosive growth of interest in this ion, mainly in the last 15 years, for many reasons, including: (i) the chemical, thermal and photochemical functionalization of the oxo groups of this cation [43,44]; (ii) the synthesis of anionic uranyl complexes with large pores for successful removal of the radiotoxic 127 Cs + ions [45]; (iii) aspects of metallosupramolecular chemistry, for example the behavior of neutral uranyl complexes with polydentate chelating Schiff-base ligands to act as anion receptors [46]; (iv) the efficient uptake of {UO 2 } 2+ by artificial and natural proteins [47]; (v) the chemistry of uranyl complexes with peroxide as ligand [48]; (vi) theoretical aspects [49,50]; (vii) the study of the reactions between the uranyl ion and polycarboxylate ligands [51]; (viii) the employment of {UO 2 } 2+ as a templating agent for the synthesis of macrocyclic complexes [52]; (ix) the efficiency of uranyl complexes to act as selective homogeneous catalysts [53]; (x) the use of uranyl complexes in separation processes associated with nuclear fuel processing and nuclear waste management [54,55]; (xi) the synthesis of heterometallic {UO 2 } 2+ -3d [54] and {UO 2 } 2+ -4f [56] complexes which have properties of hybrid materials; and (xii) the unique photocatalytic activity, i.e., light-driven (UV or Vis) catalysis, of some uranyl complexes towards several dyes, e.g., methylene blue [57]. As an example of the above areas, the UO 2 (NO 3 ) , where H 4 Ppb is benzene-1,2-diphosphonic acid [48]. The (UO 2 ) 20 clusters adopt the fullerene topology, while the (UO 2 ) 26 cluster consists of two building units, related through a C 2 axis, that are connected through organic ligands to form a closed cage.…”

Woven, Polycatenated, or Cage Structures: Effect of Modulation of Ligand Curvature in Heteroleptic Uranyl Ion Complexes

“…Besides more sophisticated synthetic approaches, the easiest pathway toward such cages is through integrative self-sorting from a mixture of ligands and unprotected metal cations, with charge separation being a particularly appealing strategy . A number of uranyl-based cages or clusters have now been described, − and although some of them include both peroxide and carboxylate, ,, phosphonate, , phosphate, ,, or carboxyphosphonate ligands, all others are homoleptic. In particular, no example is known of a cage involving different polycarboxylate donors.…”