A 2:1 dicationic complex of tetraethyl methylenebisphosphonate with uranyl ion in acetonitrile and ionic liquids.
A 2:1 dicationic complex of tetraethyl methylenebisphosphonate with uranyl ion in acetonitrile and ionic liquids.
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DOI：
10.1021/ic302005e
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发表时间：
2013-01
影响因子：
4.6
通讯作者：
Yupeng Liu;Taiwei Chu;Xiangyun Wang
中科院分区：
文献类型：
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作者：
Yupeng Liu;Taiwei Chu;Xiangyun Wang
用光谱和质谱相结合的方法研究了TEMBP与铀酰离子在乙腈和两种疏水离子液体[BMIm][NTf（2）]和[N（4111）][NTf（2）]中形成的一种新的2：1双阳离子配合物。当TEMBP配体过量（L/U > 2.0）时，铀酰完全被两个配体配位形成双阳离子配合物[UO（2）（TEMBP）（2）]（2+）。[UO（2）（TEMBP）（2）]（2+）在乙腈和两种离子液体中的紫外-可见光谱相似。[UO（2）（TEMBP）（2）]（2+）的紫外-可见光谱的振动精细结构显示出铀酰赤道面的四配位特征。[UO（2）（TEMBP）（2）]（2+）的结构对称性为D（2 h），其紫外-可见光谱与已研究的[UO（2）Cl（4）]（2-）配合物的结构相似。[UO（2）（TEMBP）（2）]（2+）的发光光谱显示出典型的电子振动带，与相应的吸收光谱的455-500 nm区域具有镜像关系。以乙腈为溶剂，采用电喷雾离子阱质谱法（ESI-ITMS）研究了[UO（2）（TEMBP）（2）]（2+）的化学计量比。“裸”二价阳离子（m/z 423）的特征是在其串联质谱中具有显著的8个峰，其间隔为14 m/z单位，代表配体通过从其乙氧基失去C（2）H（4）单位而断裂。然而，在ESI质谱中，阳离子倾向于作为与另外的配体或阴离子的弱加合物存在。加合物{[UO（2）（TEMBP）（2）]（2+）+ TEMBP}（m/z 567）和{[UO（2）（TEMBP）（2）]（2+）+ [ClO（4）]（-）}（m/z 945）在纯乙腈中是有利的，而在[BMIm][NTf（2）]（用乙腈稀释）中只有一种加合物{[UO（2）（TEMBP）（2）]（2+）+ [NTf（2）]（-）}（m/z 1126）占优势。ESI-ITMS的研究结果与光学光谱研究结果一致。
A new 2:1 dicationic complex formed by TEMBP with uranyl ion in acetonitrile and two hydrophobic ILs, [BMIm][NTf(2)] and [N(4111)][NTf(2)], has been identified with combination of optical spectroscopic and mass spectrometric studies. With excess of TEMBP ligand (L/U > 2.0), the uranyl is completely coordinated by two ligands to form a dicationic complex [UO(2)(TEMBP)(2)](2+). The UV-vis spectra of [UO(2)(TEMBP)(2)](2+) in acetonitrile and in the two ILs are similar. The vibronic fine structures in UV-vis spectrum of [UO(2)(TEMBP)(2)](2+) show characters of tetragonal coordination in the uranyl equatorial plane. The symmetry of proposed structure of [UO(2)(TEMBP)(2)](2+) is D(2h), and its UV-vis spectrum is tentatively interpreted based on the structural similarity to the well studied [UO(2)Cl(4)](2-) complex. The luminescence emission spectrum of [UO(2)(TEMBP)(2)](2+) shows typical vibronic bands, having a mirror relationship with the 455-500 nm region of the corresponding absorption spectrum. The stoichiometry of [UO(2)(TEMBP)(2)](2+) is confirmed by electrospray ionization-ion trap mass spectrometry (ESI-ITMS) studies with acetonitrile as solvent. The "naked" dication (m/z 423) is characterized by the remarkable eight peaks with interval of 14 m/z units in its tandem mass spectra, representing the fragmentation of ligands by losing C(2)H(4) units from their ethoxy groups. However, the dication tends to exist as a weak adduct with either an additional ligand or an anion in the ESI mass spectrum. The adducts {[UO(2)(TEMBP)(2)](2+) + TEMBP} (m/z 567) and {[UO(2)(TEMBP)(2)](2+) + [ClO(4)](-)} (m/z 945) are favorable in pure acetonitrile, while only one adduct {[UO(2)(TEMBP)(2)](2+) + [NTf(2)](-)} (m/z 1126) is predominant in [BMIm][NTf(2)] (diluted with acetonitrile). The results of ESI-ITMS study are consistent with those of optical spectroscopic studies.