The Reaction Chemistry of Plutonyl(VI) Chloride Complexes with Triphenyl Phosphineoxide and Triphenyl Phosphinimine

Abstract

The reaction between Ph(3)PO dissolved in acetone and "PuO(2)Cl(2)" in dilute HCl resulted in the formation of [PuO(2)Cl(2)(Ph(3)PO)(2)]. Crystallographic characterization of the acetone solvate revealed the expected axial trans plutonyl dioxo, with trans Cl and Ph(3)PO in the equatorial plane. Spectroscopic analyses ((31)P NMR, (1)H NMR, and vis/nIR) indicate the presence of both cis and trans isomers in solution, with the trans isomer being more stable. Confirmation of the higher stability of the trans versus cis isomers for [AnO(2)Cl(2)(Ph(3)PO)(2)] (An = U and Pu) was obtained through quantum chemical computational analysis, which also reveals the Pu-O(TPPO) bond to be more ionic than the U-O(TPPO) bond. Slight variation in reaction conditions led to the crystallization of two further minor products, [PuO(2)(Ph(3)PO)(4)][ClO(4)](2) and cis-[PuCl(2)(Ph(3)PO)(4)], the latter complex revealing the potential for reduction to Pu(IV). In addition, the reaction of Ph(3)PNH with [PuO(2)Cl(2)(thf)(2)](2) in anhydrous conditions gave evidence for the formation of both cis- and trans-[PuO(2)Cl(2)(Ph(3)PNH)(2)] in solution (by (31)P NMR). However, the major reaction pathway involved protonation of the ligand with the crystallographic characterization of [Ph(3)PNH(2)](2)[PuO(2)Cl(4)]. We believe that HCl/SiMe(3)Cl carried through from the small scale preparation of [PuO(2)Cl(2)(thf)(2)](2) was the source of both protons and chlorides. The fact that this chemistry was significantly different from previous uranium studies, where cis-/trans-[UO(2)Cl(2)L(2)] (L = Ph(3)PO or Ph(3)PNH) were the only products observed, provides further evidence of the unique challenges and opportunities associated with the chemistry of plutonium.

Uncovering f-element bonding differences and electronic structure in a series of 1 : 3 and 1 : 4 complexes with a diselenophosphinate ligand

“…One technique that we have found to be useful in providing additional ngerprint characterization on solid transuranic complexes is diffuse reectance electronic absorption spectroscopy. 29,[41][42][43][44][45] Comparison of the solid-state vis-NIR spectra of 5, 7, and 9 show good correlation of the 5f-6d and 5f-5f electronic transitions to those observed in solution ( Fig. 6 and ESI †), providing support for identical speciation between the two phases.…”

Probing a variation of the inverse-trans-influence in americium and lanthanide tribromide tris(tricyclohexylphosphine oxide) complexes

“…1 The study of phosphine oxides with f-elements has primarily focused on their use in extraction processes [2][3][4][5] and in (pseudo)halide/nitrate f-element starting materials. [6][7][8][9] The effect of two ligands trans to one another is most prototypically examined in the actinyls, AnO 2 n+ , where the trans-oxygens display unusually short bond distances and high bond strength, best described as bond order of three. 10 This effect, termed the inverse-trans-inuence (ITI) as a general concept has become the focus of several experimental and theoretical investigations and has evolved to be primarily applied to ligands trans to multiply bonded ligands.…”

Phosphinimine complex of organotin(IV) compounds stabilized by O,C,O-chelating ligand

“…The geometry of tin atom is best described as trigonal bipyramidal, with the methyl groups occupying the equatorial plane and the phosphinimine and the chlorine atom occupying the axial sites as defined from bonding angles C29eSn1eC31 (110.64 (13) ), C31eSn1eC30 (125.14 (14) ), C30eSn1eC29 (123.73 (14) ) and N1eSneCl1 (172.27(8) [15] and is similar to the related plutonyl(VI) chloride complex of triphenyl phosphinimine [16]. It is noteworthy, that related reaction of t-Bu 3 PNH with Me 3 SnCl does not result in the Lewis base adduct [15].…”