- Coordination Chemistry of Homoleptic Actinide(IV)-Thiocyanate Complexes
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The synthesis, X-ray crystal structure, vibrational and optical spectroscopy for the eight-coordinate thiocyanate compounds, [Et4N]4[PuIV(NCS)8], [Et4N]4[ThIV(NCS)8], and [Et4N]4[CeIII(NCS)7(H2O)] are reported. Thiocyanate was found to rapidly reduce plutonium to PuIII in acidic solutions (pH-. The optical spectrum of [Et4N][SCN] containing PuIII solution was indistinguishable from that of aquated PuIII suggesting that inner-sphere complexation with [Et4N][SCN] does not occur in water. However, upon concentration, the homoleptic thiocyanate complex [Et4N]4[PuIV(NCS)8] was crystallized when a large excess of [Et4N][NCS] was present. This compound, along with its UIV analogue, maintains inner-sphere thiocyanate coordination in acetonitrile based on the observation of intense ligand-to-metal charge-transfer bands. Spectroscopic and crystallographic data do not support the interaction of the metal orbitals with the ligand π system, but support an enhanced AnIV-NCS interaction, as the Lewis acidity of the metal ion increases from Th to Pu.
- Carter, Tyler J.,Wilson, Richard E.
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- Azido- and Thiocyanato-derivatives of Some Chlorofluorophosphate(V) Ions
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The preparation and characterisation of some solid tetra-ethylammonium chlorofluorophosphates(V), (+)(-) (1n3), the anions of which were previously known only in mixed systems, are described for the first time.Their reactions with suitable metal pseudohalides (LiN3 or AgNCS) lead to substitution of the chlorine ligands only.In some instances ligand redistribution involving fluoride occurs.Some of the derivatives have also been prepared by ligand-exchange reactions between appropriate phosphate (V) anions.Several structural assignments have been made on the basis of the observed P-F splitting patterns and the pairwise additivity of 31P n.m.r. shifts, although fluxional behaviour was observed in some cases.All the pseudohalogeno-species are unstable, the thiocyanato-compounds isolated as solids decomposing readily at room temperature.
- Dillon, Keith B.,Platt, Andrew W. G.
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