Carbon dioxide activation by a uranium(III) complex derived from a chelating bis(aryloxide) ligand

Inman, Christopher J, Frey, Alistair S P, Kilpatrick, Alexander F R, Cloke, F Geoffrey and Roe, S Mark (2017) Carbon dioxide activation by a uranium(III) complex derived from a chelating bis(aryloxide) ligand. Organometallics. ISSN 0276-7333

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Abstract

The new dianionic ligand, C6H4{p-C(CH3)2C6H2Me2O−}2 (= p-Me2bp), featuring two aryloxide donors and a central arene ring, has been synthesized, and used to prepare the mixed-ligand U(III) compound, [U(Cp*)(p-Me2bp)] which exhibits an η6-interaction with the uranium center. Reductive activation of CO2 was investigated using [U(Cp*)(p-Me2bp)] in supercritical CO2, which gave a dinuclear uranium carbonate complex,{U(Cp*)(p-Me2bp)}2(μ-η1:η2-CO3), cleanly and selectively. Reactivity studies in conventional solvents using lower pressures of CO2 showed the formation of a rare U(IV) oxalate complex, {U(Cp*)(p-Me2bp)}2(μ-η2:η2-C2O2), alongside {U(Cp*)(p-Me2bp)}2(μ-η1:η2-CO3). The relative ratio of the latter two products is temperature dependent: at low temperatures (-78 ˚C) oxalate formation is favored, whilst at room temperature the carbonate is the dominant product. The U(IV) iodide, [U(Cp*)(p-Me2bp)I], was also synthesized and used as part of an electrochemical study, the results of which showed that [U(Cp*)(p-Me2bp)] has a UIV/UIII redox couple of −2.18 V vs FeCp2+/0 as well as an possible electrochemically accessible UIII/UII reduction process at −2.56 V vs FeCp2+/0.

Item Type: Article
Schools and Departments: School of Life Sciences > Chemistry
Subjects: Q Science > QD Chemistry > QD0146 Inorganic chemistry
Depositing User: Geoff Cloke
Date Deposited: 01 Jun 2017 11:56
Last Modified: 01 Jun 2017 11:58
URI: http://sro.sussex.ac.uk/id/eprint/68284

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