Deviation Between the Chemistry of Ce(IV) and Pu(IV) and Routes to Ordered and Disordered Heterobimetallic 4f/5f and 5f/5f Phosphonates

Abstract

The heterobimetallic actinide compound UO(2)Ce(H(2)O)[C(6)H(4)(PO(3)H)(2)](2)·H(2)O was prepared via the hydrothermal reaction of U(VI) and Ce(IV) in the presence of 1,2-phenylenediphosphonic acid. We demonstrate that this is a kinetic product that is not stable with respect to decomposition to the monometallic compounds. Similar reactions have been explored with U(VI) and Ce(III), resulting in the oxidation of Ce(III) to Ce(IV) and the formation of the Ce(IV) phosphonate, Ce[C(6)H(4)(PO(3)H)(PO(3)H(2))][C(6)H(4)(PO(3)H)(PO(3))]·2H(2)O, UO(2)Ce(H(2)O)[C(6)H(4)(PO(3)H)(2)](2)·H(2)O, and UO(2)[C(6)H(4)(PO(3)H)(2)](H(2)O)·H(2)O. In comparison, the reaction of U(VI) with Np(VI) only yields Np[C(6)H(4)(PO(3)H)(2)](2)·2H(2)O and aqueous U(VI), whereas the reaction of U(VI) with Pu(VI) yields the disordered U(VI)/Pu(VI) compound, (U(0.9)Pu(0.1))O(2)[C(6)H(4)(PO(3)H)(2)](H(2)O)·H(2)O, and the Pu(IV) phosphonate, Pu[C(6)H(4)(PO(3)H)(PO(3)H(2))][C(6)H(4)(PO(3)H)(PO(3))]·2H(2)O. The reactions of Ce(IV) with Np(VI) yield disordered heterobimetallic phosphonates with both M[C(6)H(4)(PO(3)H)(PO(3)H(2))][C(6)H(4)(PO(3)H)(PO(3))]·2H(2)O (M = Ce, Np) and M[C(6)H(4)(PO(3)H)(2)](2)·2H(2)O (M = Ce, Np) structures, as well as the Ce(IV) phosphonate Ce[C(6)H(4)(PO(3)H)(PO(3)H(2))][C(6)H(4)(PO(3)H)(PO(3))]·2H(2)O. Ce(IV) reacts with Pu(IV) to yield the Pu(VI) compound, PuO(2)[C(6)H(4)(PO(3)H)(2)](H(2)O)·3H(2)O, and a disordered heterobimetallic Pu(IV)/Ce(IV) compound with the M[C(6)H(4)(PO(3)H)(PO(3)H(2))][C(6)H(4)(PO(3)H)(PO(3))]·2H(2)O (M = Ce, Pu) structure. Mixtures of Np(VI) and Pu(VI) yield disordered heterobimetallic Np(IV)/Pu(IV) phosphonates with both the An[C(6)H(4)(PO(3)H)(PO(3)H(2))][C(6)H(4)(PO(3)H)(PO(3))]·2H(2)O (M = Np, Pu) and An[C(6)H(4)(PO(3)H)(2)](2)·2H(2)O (M = Np, Pu) formulas.

From Yellow to Black: Dramatic Changes between Cerium(IV) and Plutonium(IV) Molybdates

“…In the tetravalent state, discrepancies have been shown between Ce(IV) and Pu(IV) as well as between early An(IV) and transuranic An(IV). [4][5][6][7][8][9][10][11][12][13][14] Exploration of this field is filled with opportunity as there are only a few systems that have systematically spanned the lanthanide and actinide series such as the aquo-triflates, phosphonates, and phosphites. [15][16][17][18][19][20][21][22][23][24][25] It is in this objective we have chosen to explore the rare earth molybdates.…”

Structural chemistry of uranium phosphonates

“…Various cationic species, including alkaline earth metals, amines, ionic liquids, and crown ether complexes, can serve as structure-directing agents. Only two examples of uranyl 1,2-phenylenediphosphonate compounds have been reported [49], and no uranyl phosphonates prepared with 1,3-phenylenediphosphonic acid have been reported.…”

“…Only two homometallic uranyl phosphonates have been reported using the 1,2-phenylenediphosphonate ligand [49], and both are layered structures (Fig. 20).…”

“…For rare earth-bearing uranyl phosphonates, only Ce(H 2 O)(UO 2 )(o-bbpH) 2 ·H 2 O has been isolated [49], and it features a layered structure (Fig. 27).…”

“…27. The layered structure of Ce(H2O)(UO2)(o-bbpH)2·H2O with two dimeric units [49]. ligands to form a layered arrangement.…”