The QUILL Research Centre, School of Chemistry and Chemical Engineering, Queen's University Belfast, David Keir Building, Stranmillis Road, Belfast BT9 5AG, United Kingdom.
Inorg Chem. 2010 Apr 5;49(7):3351-60. doi: 10.1021/ic902406h.
Uranium(VI) oxide has been dissolved in three different ionic liquids functionalized with a carboxyl group: betainium bis[(trifluoromethyl)sulfonyl]imide, 1-(carboxymethyl)-3-methylimidazolium bis[(trifluoromethyl)sulfonyl]imide, and N-(carboxymethyl)-N-methylpyrrolidinium bis[(trifluoromethyl)sulfonyl]imide. The dissolution process results in the formation of uranyl complexes with zwitterionic carboxylate ligands and bis[(trifluoromethyl)sulfonyl]imide (bistriflimide) counterions. An X-ray diffraction study on single crystals of the uranyl complexes revealed that the crystal structure strongly depends on the cationic core appended to the carboxylate groups. The betainium ionic liquid gives a dimeric uranyl complex, the imidazolium ionic liquid a monomeric complex, and the pyrrolidinium ionic liquid a one-dimensional polymeric uranyl complex. Extended X-ray absorption fine structure measurements have been performed on the betainium uranyl complex. The absorption and luminescence spectra of the uranyl betainium complex have been studied in the solid state and dissolved in water, in acetonitrile, and in the ionic liquid betainium bistriflimide. The carboxylate groups remain coordinated to uranyl in acetonitrile and in betainium bistriflimide but not in water.
六氧化铀已溶解在三种不同的离子液体中，这些离子液体都带有羧基官能团：甜菜碱双[(三氟甲基)磺酰]亚胺、1-(羧甲基)-3-甲基咪唑双[(三氟甲基)磺酰]亚胺和 N-(羧甲基)-N-甲基吡咯烷双[(三氟甲基)磺酰]亚胺。溶解过程导致形成具有两性离子羧酸根配体和双[(三氟甲基)磺酰]亚胺（双三氟甲烷磺酰亚胺）抗衡离子的铀酰配合物。对铀酰配合物单晶的 X 射线衍射研究表明，晶体结构强烈依赖于附加在羧酸根上的阳离子核。甜菜碱离子液体生成二聚铀酰配合物，咪唑离子液体生成单体配合物，而吡咯烷离子液体生成一维聚合铀酰配合物。对甜菜碱铀酰配合物进行了扩展 X 射线吸收精细结构测量。研究了铀酰甜菜碱配合物在固态以及溶解在水中、乙腈中和甜菜碱双三氟甲烷磺酰亚胺中的吸收和发光光谱。在乙腈和甜菜碱双三氟甲烷磺酰亚胺中，羧酸根仍然与铀酰配位，但在水中则不是。
