Sequestered plutonium:: [PuIV{5LIO(Me-3,2-HOPO)}2] -: The first structurally characterized plutonium hydroxypyridonate complex

The first single-crystal X-ray diffraction analysis of a hydroxypyridonate plutonium(iv) complex is presented, that of the tetradentate ligand 5LIO(Me-3,2-HOPO) with Pu-IV. The [Pu-IV{5LIO(Me-3,2-HOPO)}(2)] Complex crystallizes in the space group Pna2(1) with the asymmetric unit cell containing two unique eight-coordinate plutonium complexes and one perchlorate anion. According to shape measure analysis, the geometry of both Pu centers is closest to a bicapped trigonal prism (C-2v symmetry, for Pu 1: S(C-2v) = 13.48 degrees, S(D-4d) = 15.43 degrees, S(D-4d) = 16.10 degrees). The average bond length for the Pu-O(phenolic) is 2.31(4) angstrom, whereas the Pu-O(amide) distances are slightly longer, averaging 2.40(2) angstrom. The preparative chemistry of this compound and the implications of the structure are discussed.