Synthesis and Crystal Structure of the U(VI) Complex with Triphenylphosphine Oxide {UO2[OP(C6H5)3]4}(ClO4)2

Abstract

Data on synthesis and structure of the U(VI) complex with triphenylphosphine oxide (TPPO) are presented. Single crystals were grown and the structure of this compound was determined [monoclinic unit cell: a = 9.795(3), b = 25.246(6), c = 14.086(4) A, β = 99.86(2)°, space group P21/c, Z = 2, V = 3431.7(15) A3, dcalc = 1.534 g cm-3; Siemens P3/PC, MoKα radiation, graphite monochromator, ω/2thetas; scanning, 2947 unique reflections, direct method, R1 = 0.0401 for 2261 observed reflections, wR2 = 0.1194 for 2947 unique reflections]. The crystal structure consists of complex cations {UO2[OP(C6H5)3]4}2+ and ClO4- anions. The U(VI) atom has a tetragonal-bipyramidal oxygen surrounding with coordination number (CN) 6. The UO2 group is linear: the O = U = O bond angle is 180.0°, and the U = O bond length is 1.750(6) A. The square equatorial coordination plane of the bipyramid is formed by oxygen atoms of four TPPO molecules, the U-Oeq bond lengths vary from 2.289(6) to 2.307(6) A (average 2.298 A), and the Oeq-U-Oeq bond angles are close to 90°.