Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
平田 早紀子*; 日下 良二; 明地 省吾*; 為国 誠太*; 奥寺 洸介*; 浜田 昇賢*; 坂本 知優*; 本田 匠*; 松下 高輔*; 村松 悟*; et al.
Inorganic Chemistry, 62(1), p.474 - 486, 2023/01
被引用回数:0 パーセンタイル:0.01(Chemistry, Inorganic & Nuclear)A new technique, surface-enhanced infrared absorption (SEIRA) spectroscopy, was used for the structural investigation of lanthanide (Ln) and actinide (An) complexes containing organic ligands. We synthesized thiol derivatives of organic ligands with coordination sites similar to those of diglycolamide (DGA), Cyanex-272, and -tetrakis(2-pyridinylmethyl)-1,2-ethanediamine (TPEN), which have been used for separating Ln and An through solvent extraction. These ligands were attached on a gold surface deposited on an Si prism through S-Au covalent bonds; the gold surface enhanced the IR absorption intensity of the ligands. Aqueous solutions of Ln (Eu, Gd, Tb) and An (Am) ions were loaded onto the gold surface to form ion complexes. The IR spectra of the ion complexes were obtained using FT-IR spectroscopy in the attenuated total reflection mode. In this study, we developed a new sample preparation method for SEIRA spectroscopy that enabled us to obtain the IR spectra of the complexes with a small amount of ion solution (5 L). This is a significant advantage for the IR measurement of radiotoxic Am complexes. In the IR spectra of DGA, the band attributed to C=O stretching vibrations at 1630 cm shifted to a lower wavenumber by 20 cm upon complexation with Ln and An ions. Moreover, the amount of the red-shift was inversely proportional to the extraction equilibrium constant reported in previous studies on solvent extraction. The coordination ability of DGA toward Ln and An ions could be assessed using the band position of the C=O band. The Cyanex-272- and TPEN-like ligands synthesized in this report also showed noticeable SEIRA signals for Ln and An complexes. This study indicates that SEIRA spectroscopy can be used for the structural investigation of ion complexes and provides a microscopic understanding of selective extraction of Ln and An.
日下 良二; 渡邉 雅之
井口 佳哉*; 平田 早紀子*; 明地 省吾*
【課題】少量の試料を密閉空間で薄く均一に広げることが可能な赤外分光分析の試料台を提供する。 【解決手段】試料Xを配置可能な試料配置面11を有する光学素子10と、試料配置面の面方向と交差する方向に貫通する試料導入孔31を有する試料保持部材30と、試料配置面に向かって突出し、試料導入孔に嵌合可能な突出部42を有する蓋部材40と、を備え、光学素子10、試料保持部材30および蓋部材40は、この順に重ねられ、試料導入孔、試料配置面および突出部の先端面42Aにより密閉空間が形成され、先端面42Aが、密閉空間に封入された試料Xを、試料配置面11に向かって押圧可能に構成される。
明地 省吾*; 平田 早紀子*; 日下 良二; 本田 匠*; 為国 誠太*; 村松 悟*; 齋藤 健一*; 平尾 岳大*; 灰野 岳晴*; 渡邉 雅之; et al.
no journal, ,
Recently, we have been performing surface-enhanced infrared absorption (SEIRA) spectroscopy of Eu complexes, aiming for clarifying the origin of selectivity of O-donor/N-donor ligands toward lanthanides (Ln)/minor actinides (MA) in radioactive waste treatments. In this study, we improved the SEIRA setup to extend the study to complexes of Am (MA), which is a radioactive nuclide. We made a new sample vessel with smaller internal volume and higher sealing ability, where we successfully reduced the radiation exposure (less than 1 Sv) during the experiment. In the actual measurement of AmDGA complex, the absorption of the C=O stretching of the amide unit was observed at 1621 cm; it is redshifted by 8 cm from the Eu complex, one of the lanthanides, which was supported by theoretical calculations.