Kumar Satendra, Maji S, Joseph M, Sankaran K
Materials Chemistry Division, Chemistry Group, Indira Gandhi Centre for Atomic Research, Kalpakkam 603 102, India.
Fuel Chemistry Division, Chemistry Group, Indira Gandhi Centre for Atomic Research, Kalpakkam 603 102, India.
Spectrochim Acta A Mol Biomol Spectrosc. 2015 Mar 5;138:509-16. doi: 10.1016/j.saa.2014.11.033. Epub 2014 Dec 5.
Benzoic acid (BA) is shown to sensitize and enhance the luminescence of uranyl ion in acetonitrile medium. Luminescence spectra and especially UV-Vis spectroscopy studies reveal the formation of tri benzoate complex of uranyl i.e. UO2(C6H5COO)3 which is highly luminescent. In particular, three sharp bands at 431, 443, 461nm of absorption spectra provides evidence for tri benzoate specie of uranyl in acetonitrile medium. The luminescence lifetime of uranyl in this complex is 68μs which is much more compared to the lifetime of uncomplexed uranyl (20μs) in acetonitrile medium. In contrary to aqueous medium where uranyl benzoate forms 1:1 and 1:2 species, spectroscopic data reveal formation of 1:3 complex in acetonitrile medium. Addition of water to acetonitrile results in decrease of luminescence intensity of this specie and the luminescence features implode at 20% (v/v) of water content. For the first time, to the best of our knowledge, the existence of UO2(C6H5COO)3 specie in acetonitrile is reported. Mechanism of luminescence enhancement is discussed.
苯甲酸（BA）已被证明在乙腈介质中能使铀酰离子敏化并增强其发光。发光光谱，尤其是紫外-可见光谱研究揭示了铀酰的三苯甲酸配合物即UO2(C6H5COO)3的形成，该配合物具有很强的发光性。特别是，吸收光谱在431、443、461nm处的三个尖锐峰为乙腈介质中铀酰的三苯甲酸物种提供了证据。该配合物中铀酰的发光寿命为68μs，与乙腈介质中未配位的铀酰（20μs）的寿命相比要长得多。与水介质中苯甲酸铀酰形成1:1和1:2物种不同，光谱数据表明在乙腈介质中形成了1:3配合物。向乙腈中加水会导致该物种的发光强度降低，当水含量为20%（v/v）时发光特征消失。据我们所知，首次报道了UO2(C6H5COO)3物种在乙腈中的存在。讨论了发光增强的机制。
