Arnold Polly L, Puig-Urrea Laura, Wells Jordann A L, Yuan Dan, Cruickshank Faye L, Young Rowan D
EaStCHEM School of Chemistry, Joseph Black Building, The King's Buildings, The University of Edinburgh, Edinburgh, EH9 3FJ, UK.
Dalton Trans. 2019 Apr 9;48(15):4894-4905. doi: 10.1039/c8dt05051a.
The boroxide ligand [OBAr2]- (Ar = Mes, Trip) is shown to be able to support both UIII and UIV centres for the first time. The synthesis and structures of homoleptic and heteroleptic UIII and UIV complexes are reported. The UX3 complex with larger substituents, [U(OBTrip2)3]2, exhibits greater thermal stability compared to less encumbered [U(OBMes2)3]2 but reacts with a smaller range of the small molecules tested to date. Initial studies on their capacity to participate in small molecule chemistry show that dark purple [U(OBMes2)3]2 binds and/or reductively activates a variety of small molecules such as pyridine-oxide, triphenylphosphineoxide, sulfur, and dicyclohexylcarbodiimide. While [U(OBMes2)3]2 shows no reaction with CO or CO2, [U(OBTrip2)3]2 is oxidised by both, in the former case forming [U(OBTrip2)4], and in the latter case forming a small quantity of the structurally characterised μ-carbonate product [(μ-CO3){U(OBTrip2)3}2].
首次证明硼氧化物配体[OBAr₂]⁻（Ar = Mes，Trip）能够同时支持UIII和UIV中心。报道了同配和异配UIII和UIV配合物的合成及结构。与位阻较小的[U(OBMes₂)₃]₂相比，具有较大取代基的UX₃配合物[U(OBTrip₂)₃]₂表现出更高的热稳定性，但与迄今为止测试的小分子反应范围较小。对它们参与小分子化学能力的初步研究表明，深紫色的[U(OBMes₂)₃]₂能结合和/或还原活化多种小分子，如吡啶氧化物、三苯基氧化膦、硫和二环己基碳二亚胺。虽然[U(OBMes₂)₃]₂与CO或CO₂不发生反应，但[U(OBTrip₂)₃]₂会被二者氧化，在前一种情况下形成[U(OBTrip₂)₄]，在后一种情况下形成少量结构已表征的μ - 碳酸盐产物[(μ - CO₃){U(OBTrip₂)₃}₂]。
