The reaction chemistry of plutonyl(VI) chloride complexes with triphenyl phosphineoxide and triphenyl phosphinimine.

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.

Neptunium(vi) chain and neptunium(vi/v) mixed valence cluster complexes.

The synthesis of [Np(VI)O(2)Cl(2)(thf)](n) offers the potential for more detailed exploration of neptunyl(vi) chemistry, while the synthesis of the mixed valence cluster complex [{Np(VI)O(2)Cl(2)}{Np(V)O(2)Cl(thf)(3)}(2)] allows molecular neptunyl(v) 'cation-cation' interactions to be probed.

Hydrogen bonding and short contacts in [2,4,6-tris(trifluoromethyl)phenyl]phosphinic acid.

In the title compound, C(9)H(4)F(9)O(2)P, molecules are linked by a single O-H...O hydrogen bond into chains related to those in phenylphosphinic acid. There are short intramolecular F...P contacts.

Probing the local coordination environment and nuclearity of uranyl(VI) complexes in non-aqueous media by emission spectroscopy.

We describe the synthesis, solid state and solution properties of two families of uranyl(VI) complexes that are ligated by neutral monodentate and anionic bidentate P=O, P=NH and As=O ligands bearing pendent phenyl chromophores. The uranyl(VI) ions in these complexes possess long-lived photoluminescent LMCT (3)Π(u) excited states, which can be exploited as a sensitive probe of electronic structure, bonding and aggregation behaviour in non-aqueous media. For a family of well defined complexes of given symmetry in trans-[UO(2)Cl(2)(L(2))] (L = Ph(3)PO (1), Ph(3)AsO (2) and Ph(3)PNH (3)), the emission spectral profiles in CH(2)Cl(2) are indicative of the strength of the donor atoms bound in the equatorial plane and the uranyl bond strength; the uranyl LMCT emission maxima are shifted to lower energy as the donor strength of L increases. The luminescence lifetimes in fluid solution mirror these observations (0.87-3.46 µs) and are particularly sensitive to vibrational and bimolecular deactivation. In a family of structurally well defined complexes of the related anion, tetraphenylimidodiphosphinate (TPIP), monometallic complexes, [UO(2)(TPIP)(thf)] (4), [UO(2)(TPIP)(Cy(3)PO)] 5), a bimetallic complex [UO(2)(TPIP)(2)](2) (6) and a previously known trimetallic complex, [UO(2)(TPIP)(2)](3) (7) can be isolated by variation of the synthetic procedure. Complex 7 differs from 6 as the central uranyl ion in 7 is orthogonally connected to the two peripheral ones via uranyl → uranium dative bonds. Each of these oligomers exhibits a characteristic optical fingerprint, where the emission maxima, the spectral shape and temporal decay profiles are unique for each structural form. Notably, excited state intermetallic quenching in the trimetallic complex 7 considerably reduces the luminescence lifetime with respect to the monometallic counterpart 5 (from 2.00 µs to 1.04 µs). This study demonstrates that time resolved and multi-parametric luminescence can be of value in ascertaining solution and structural forms of discrete uranyl(VI) complexes in non-aqueous solution.

A structural and theoretical investigation of equatorial cis and trans uranyl phosphinimine and uranyl phosphine oxide complexes UO2Cl2(Cy3PNH)2 and UO2Cl2(Cy3PO)2.

Phosphinimine ligands (Cy3PNH) readily react with UO2Cl2(THF)3 (THF=tetrahydrofuran) to give UO2Cl2(Cy3PNH)2, which contains strong U-N interactions and exists as cis and trans isomers in the solid and solution state. Solution NMR experiments and computational analysis both support the trans form as the major isomer in solution, although the cis isomer becomes more stabilized with an increase in the dielectric constant of the solvent. Mayer bond orders, energy decomposition analysis, and examination of the molecular orbitals and total electron densities support a more covalent bonding interaction in the U-NHPCy3 bond compared with the analogous bond of the related U-OPCy3 compounds.

trans-Di-mu-bromo-bis[bromo(triethylphosphine-kappaP)platinum(II)].

The title compound, [Pt2Br4(C6H15P)2], is a centrosymmetric dinuclear platinum(II) complex consisting of two square-planar platinum centres connected by two bridging Br atoms.

Preference for nitrogen versus oxygen donor coordination in uranyl- and neptunyl(VI) complexes.

The first actinyl phosphinimine complexes have been synthesized and, in the case of uranium, exhibit strong U-N interactions. Competition reactions clearly demonstrate a surprising preference for R3P=NH ligands over R3P=O in the system [AnO2Cl2(R3PX)2] (An = U(VI), Np(VI); R = Ph, Cy; X = O, NH). Spectroscopic evidence for N-donor coordination to [NpO2]2+ in solution indicates chemical similarities to the [UO2]2+ moiety.