Tris(pyrazolyl)borate half-sandwich complexes of trivalent uranium incorporating the [C8H6{SiiPr3-1,4}2]2− and [C8H4{SiiPr3-1,4}2]2− ligands

Farnaby, J. H. , Cloke, F. G. N., Coles, M. P., Green, J. C. and Aitken, G. (2010) Tris(pyrazolyl)borate half-sandwich complexes of trivalent uranium incorporating the [C8H6{SiiPr3-1,4}2]2− and [C8H4{SiiPr3-1,4}2]2− ligands. Comptes Rendus Chimie, 13(6-7), pp. 812-820. (doi: 10.1016/j.crci.2010.04.017)

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Abstract

The reaction of UI3 in THF with KTpMe2 and the subsequent addition of [K2(C8H6{SiiPr3-1,4}2)] or [K2(C8H4{SiiPr3-1,4}2)] yields dark red [U(κ3-TpMe2)(C8H6{SiiPr3-1,4}2)] 1 and purple [U(κ3-TpMe2)(C8H4{SiiPr3-1,4}2)] 2, respectively. The 1H NMR of 1 at room temperature suggests a rigid structure, whereas 2 is fluxional in solution on the NMR timescale. 1 is unreactive towards CO, CO2 and MeNC under mild conditions; density functional calculations were used to compare the electronic and steric effects of the TpMe2vs. Cp* ligands in mixed sandwich complexes of the type [U(L)(C8H6{SiH3-1,4}2)] (L = Cp* or (κ3-TpMe2)). On heating at 80 °C, 1 reacts with excess MeNC to yield [U(C8H6{SiiPr3-1,4}2)(κ2-dmpz)2(η1-CNMe)] 3. The structures of 1–3 have been determined by single crystal X-ray diffraction.

Item Type:Articles
Status:Published
Refereed:Yes
Glasgow Author(s) Enlighten ID:Farnaby, Dr Joy
Authors: Farnaby, J. H., Cloke, F. G. N., Coles, M. P., Green, J. C., and Aitken, G.
College/School:College of Science and Engineering > School of Chemistry
Journal Name:Comptes Rendus Chimie
Publisher:Elsevier
ISSN:1631-0748
ISSN (Online):1878-1543
Published Online:04 June 2010

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