Preparation and properties of trichlorobis(pentane-2,4-dionato)protactinium(V), tetrakis(1,3-diphenylpropane-1,3-dionato)protactinium(IV), and tetrakis(pentane-2,4-dionato)actinoid(IV) complexes

Abstract

Trichlorobis(pentane-2,4-dionato)protactinium(V), [PaCl₃(pd)₂], has been obtained from the reaction between protactinium pentachloride and pentane-2,4-dione (Hpd) in methylene dichloride, and [Pa(dppd)₄] and [Pa(dp)₄](dppd = 1,3-diphenylpropane-1,3-dionato) from reactions involving the thallium salt of the appropriate chelate and [Et₄N]₂[PaCl₆] and PaCl₄, respectively, in oxygen-free non-aqueous solvents. Oxidation of [Pu(pd)₃] in solvents such as benzene and ethanol in the presence of Hpd yields [Pu(pd)₄]. Attempts to prepare [Am(pd)₄] and complexes of the type M[Th(pd)₅](M = univalent cation) have been unsuccessful. X-Ray diffraction results are reported for the above complexes, together with details of conditions necessary for formation of the α and β phases of the tetrakis(pentane-2,4-dionato)actinoid(IV) complexes. Solid-state spectral results (0·5–2·2 µm) are provided for β-[Pa(pd)₄], β-[U(pd)₄], β-[Pu(pd)₄], and [Pu(pd)₃] together with i.r. results for these complexes, those of the type [M(pd)₄](M = Zr, Hf, Ce, and Th), and [PaCl₃(pd)₂].