Crystal Structure of U(VI) Peroxo Complex with Triphenylphosphine Oxide {(UO2)2O2[OP(C6H5)3]6}(ClO4)2

Abstract

The peroxo complex {(UO2)2O2[OP(C6H5)3]6}(ClO4)2 was synthesized, and its crystal structure was determined [triclinic unit cell: a = 10.523(2), b = 16.242(3), c = 16.978(3) A, α = 65.79(3)°, β = 85.06(3)°, γ = 77.14(3)°, space group P-1, Z = 1, V = 2580.1(9) A3, d c a l c = 2.789 g cm- 3; CAD4, MoK α, graphite monochromator, direct method, R 1 = 0.0368 for 3115 observed reflections, wR 2 = 0.1107 for 4403 unique reflections, 622 refined parameters]. {(UO2)2O2[OP(C6H5)3]6}(ClO4)2 has monomeric structure and consists of the complex cations {(UO2)2O2[OP(C6H5)3]6}2 + and ClO4 - anions. The uranium atom has a pentagonal-bipyramidal oxygen surrounding (CN 7). Uranyl groups UO2 2 + are linear and symmetrical, the U = O bond lengths are 1.780(8) and 1.787(8) A, the O(1) = U = O(2) bond angles are 178.7(4) A. The equatorial planes of bipyramids are formed by oxygen atoms of three TPPO molecules [U-OT P P O 2.352(8)-2.368(7) A, average 2.362 A] and peroxo group O2 2 - [U-Op e r 2.285(8) and 2.323(8) A, average 2.305 A]. Two pentagonal bipyramids sharing the common edge O(3)-O(3)(a) form the centrosymmetrical peroxo-bridged diuranyl complex {(UO2)2O2[OP(C6H5)3]6}2 + with the [UO2O2UO2]2 + core. The length of the O(3)-O(3)( 9a ) edge is 1.426(15) A.