ネプツニウム(IV)イオンの5f配位子場遷移が 中心対称場では厳密に禁制となることを証明

ネプツニウム(IV)イオンの5f配位子場遷移が 中心対称場では厳密に禁制となることを証明

WRHIからのお知らせおすすめ

先導原子力研究所 鷹尾康一朗准教授と津島悟特任准教授の共著論文

“Crystallization of colourless hexanitratoneptunate(iv) with anhydrous H+ countercations trapped in a hydrogen bonded polymer with diamide linkers”

が、RSC Adv.に掲載されました。(DOI: 10.1039/C9RA10090C

詳しくはこちら 

 

<Abstract>

Colourless crystalline compounds of centrosymmetric [Np(NO3)6]2− were yielded from 3 M HNO3 aq in the presence of double-headed 2-pyrrolidone derivatives (L). In the obtained crystal structures, H+ was also involved as a countercation to compensate for the negative charge of [Np(NO3)6]2−, where the initial hydration around H+ was fully removed during crystallization despite it having the strongest hydration enthalpy. Instead, this anhydrous H+ was captured by L to form a [H+L]n hydrogen bonded polymer. In [Np(NO3)6]2−, the Np4+ centre is twelve-coordinated with 6 bidentate NO3, and therefore, present in an icosahedral geometry bearing inversion centre. In such a centrosymmetric system, any f–f transitions stemming from the 5f3 electronic configuration of Np4+ are electric-dipole forbidden. This is the reason why the compounds currently obtained were colourless unlike ordinary Np(IV) species, which are olive-green.